Android WebView 添加上传下载复制粘贴和 Cookie 管理器
Android WebView adding Uploading Download Copy and Paste and Cookie Manager
我正在尝试为我的论坛创建一个应用程序，这样用户就不必在他们的移动设备上使用浏览器或使用其他应用程序。我 运行 现在正在处理应用程序崩溃的问题，但不确定原因。我是这方面的新手，所以当涉及到代码错误时，我真的不知道该寻找什么，也许我可以得到一些帮助来找出我做错了什么？
我可能需要更改代码中的某些内容，请随时告诉我，但请告诉我需要更改哪些内容才能取悦。我还需要弄清楚如何向应用程序添加复制和粘贴功能以及让应用程序为 "remember me".
设置 cookie 的能力
package com.technologx.technologx;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.DownloadManager;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.view.Window;
import android.webkit.CookieSyncManager;
import android.webkit.JsResult;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebSettings.PluginState;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.io.File;
import java.lang.reflect.Method;
import java.net.URL;
public class MainActivity extends Activity {
private WebView webView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Adds Progress Bar Support
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
// Makes Progress Bar Visible
getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
// Use forum.xml as webview layout
setContentView(R.layout.activity_main);
webView.setWebViewClient(new WebViewClient());
webView = (WebView) findViewById(R.id.activity_main_webview);
webView.getSettings().setJavaScriptEnabled(true);
// Adds Zoom Control (You may not need this)
webView.getSettings().setSupportZoom(true);
// Enables Multi-Touch. if supported by ROM
webView.getSettings().setBuiltInZoomControls(true);
initWebView(webView);
webView.loadUrl("https://technologx.com"); // TODO input your url
// This will handle downloading. It requires Gingerbread, though
final DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
// This is where downloaded files will be written, using the package name isn't required
// but it's a good way to communicate who owns the directory
final File destinationDir = new File (Environment.getExternalStorageDirectory(), getPackageName());
if (!destinationDir.exists()) {
destinationDir.mkdir(); // Don't forget to make the directory if it's not there
}
webView.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading (WebView view, String url) {
boolean shouldOverride = false;
// We only want to handle requests for mp3 files, everything else the webview
// can handle normally
if (url.endsWith(".zip")) {
shouldOverride = true;
Uri source = Uri.parse(url);
// Make a new request pointing to the mp3 url
DownloadManager.Request request = new DownloadManager.Request(source);
// Use the same file name for the destination
File destinationFile = new File (destinationDir, source.getLastPathSegment());
request.setDestinationUri(Uri.fromFile(destinationFile));
// Add it to the manager
manager.enqueue(request);
}
return shouldOverride;
}
});
}
private final static Object methodInvoke(Object obj, String method, Class<?>[] parameterTypes, Object[] args) {
try {
Method m = obj.getClass().getMethod(method, new Class[] { boolean.class });
m.invoke(obj, args);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private void initWebView(WebView webView) {
WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setAllowFileAccess(true);
settings.setDomStorageEnabled(true);
settings.setCacheMode(WebSettings.LOAD_NO_CACHE);
settings.setLoadWithOverviewMode(true);
settings.setUseWideViewPort(true);
settings.setSupportZoom(true);
// settings.setPluginsEnabled(true);
methodInvoke(settings, "setPluginsEnabled", new Class[] { boolean.class }, new Object[] { true });
// settings.setPluginState(PluginState.ON);
methodInvoke(settings, "setPluginState", new Class[] { PluginState.class }, new Object[] { PluginState.ON });
// settings.setPluginsEnabled(true);
methodInvoke(settings, "setPluginsEnabled", new Class[] { boolean.class }, new Object[] { true });
// settings.setAllowUniversalAccessFromFileURLs(true);
methodInvoke(settings, "setAllowUniversalAccessFromFileURLs", new Class[] { boolean.class }, new Object[] { true });
// settings.setAllowFileAccessFromFileURLs(true);
methodInvoke(settings, "setAllowFileAccessFromFileURLs", new Class[] { boolean.class }, new Object[] { true });
webView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
webView.clearHistory();
webView.clearFormData();
webView.clearCache(true);
webView.setWebChromeClient(new MyWebChromeClient());
// webView.setDownloadListener(downloadListener);
}
UploadHandler mUploadHandler;
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == Controller.FILE_SELECTED) {
// Chose a file from the file picker.
if (mUploadHandler != null) {
mUploadHandler.onResult(resultCode, intent);
}
}
super.onActivityResult(requestCode, resultCode, intent);
}
class MyWebChromeClient extends WebChromeClient {
public MyWebChromeClient() {
}
private String getTitleFromUrl(String url) {
String title = url;
try {
URL urlObj = new URL(url);
String host = urlObj.getHost();
if (host != null && !host.isEmpty()) {
return urlObj.getProtocol() + "://" + host;
}
if (url.startsWith("file:")) {
String fileName = urlObj.getFile();
if (fileName != null && !fileName.isEmpty()) {
return fileName;
}
}
} catch (Exception e) {
// ignore
}
return title;
}
@Override
public boolean onJsAlert(WebView view, String url, String message, final JsResult result) {
String newTitle = getTitleFromUrl(url);
new AlertDialog.Builder(MainActivity.this).setTitle(newTitle).setMessage(message).setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
result.confirm();
}
}).setCancelable(false).create().show();
return true;
// return super.onJsAlert(view, url, message, result);
}
@Override
public boolean onJsConfirm(WebView view, String url, String message, final JsResult result) {
String newTitle = getTitleFromUrl(url);
new AlertDialog.Builder(MainActivity.this).setTitle(newTitle).setMessage(message).setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
result.confirm();
}
}).setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
result.cancel();
}
}).setCancelable(false).create().show();
return true;
// return super.onJsConfirm(view, url, message, result);
}
// Android 2.x
public void openFileChooser(ValueCallback<Uri> uploadMsg) {
openFileChooser(uploadMsg, "");
}
// Android 3.0
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
openFileChooser(uploadMsg, "", "filesystem");
}
// Android 4.1
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
mUploadHandler = new UploadHandler(new Controller());
mUploadHandler.openFileChooser(uploadMsg, acceptType, capture);
}
// Android 4.4, 4.4.1, 4.4.2
// openFileChooser function is not called on Android 4.4, 4.4.1, 4.4.2,
// you may use your own java script interface or other hybrid framework.
// Android 5.0.1
public boolean onShowFileChooser(
WebView webView, ValueCallback<Uri[]> filePathCallback,
FileChooserParams fileChooserParams) {
String acceptTypes[] = fileChooserParams.getAcceptTypes();
String acceptType = "";
for (int i = 0; i < acceptTypes.length; ++ i) {
if (acceptTypes[i] != null && acceptTypes[i].length() != 0)
acceptType += acceptTypes[i] + ";";
}
if (acceptType.length() == 0)
acceptType = "*/*";
final ValueCallback<Uri[]> finalFilePathCallback = filePathCallback;
ValueCallback<Uri> vc = new ValueCallback<Uri>() {
@Override
public void onReceiveValue(Uri value) {
Uri[] result;
if (value != null)
result = new Uri[]{value};
else
result = null;
finalFilePathCallback.onReceiveValue(result);
}
};
openFileChooser(vc, acceptType, "filesystem");
return true;
}
};
class Controller {
final static int FILE_SELECTED = 4;
Activity getActivity() {
return MainActivity.this;
}
}
// public class UploadHandler {
class UploadHandler {
/*
* The Object used to inform the WebView of the file to upload.
*/
private ValueCallback<Uri> mUploadMessage;
private String mCameraFilePath;
private boolean mHandled;
private boolean mCaughtActivityNotFoundException;
private Controller mController;
public UploadHandler(Controller controller) {
mController = controller;
}
String getFilePath() {
return mCameraFilePath;
}
boolean handled() {
return mHandled;
}
void onResult(int resultCode, Intent intent) {
if (resultCode == Activity.RESULT_CANCELED && mCaughtActivityNotFoundException) {
// Couldn't resolve an activity, we are going to try again so skip
// this result.
mCaughtActivityNotFoundException = false;
return;
}
Uri result = intent == null || resultCode != Activity.RESULT_OK ? null
: intent.getData();
// As we ask the camera to save the result of the user taking
// a picture, the camera application does not return anything other
// than RESULT_OK. So we need to check whether the file we expected
// was written to disk in the in the case that we
// did not get an intent returned but did get a RESULT_OK. If it was,
// we assume that this result has came back from the camera.
if (result == null && intent == null && resultCode == Activity.RESULT_OK) {
File cameraFile = new File(mCameraFilePath);
if (cameraFile.exists()) {
result = Uri.fromFile(cameraFile);
// Broadcast to the media scanner that we have a new photo
// so it will be added into the gallery for the user.
mController.getActivity().sendBroadcast(
new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, result));
}
}
mUploadMessage.onReceiveValue(result);
mHandled = true;
mCaughtActivityNotFoundException = false;
}
void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
final String imageMimeType = "image/*";
final String videoMimeType = "video/*";
final String audioMimeType = "audio/*";
final String mediaSourceKey = "capture";
final String mediaSourceValueCamera = "camera";
final String mediaSourceValueFileSystem = "filesystem";
final String mediaSourceValueCamcorder = "camcorder";
final String mediaSourceValueMicrophone = "microphone";
// According to the spec, media source can be 'filesystem' or 'camera' or 'camcorder'
// or 'microphone' and the default value should be 'filesystem'.
String mediaSource = mediaSourceValueFileSystem;
if (mUploadMessage != null) {
// Already a file picker operation in progress.
return;
}
mUploadMessage = uploadMsg;
// Parse the accept type.
String params[] = acceptType.split(";");
String mimeType = params[0];
if (capture.length() > 0) {
mediaSource = capture;
}
if (capture.equals(mediaSourceValueFileSystem)) {
// To maintain backwards compatibility with the previous implementation
// of the media capture API, if the value of the 'capture' attribute is
// "filesystem", we should examine the accept-type for a MIME type that
// may specify a different capture value.
for (String p : params) {
String[] keyValue = p.split("=");
if (keyValue.length == 2) {
// Process key=value parameters.
if (mediaSourceKey.equals(keyValue[0])) {
mediaSource = keyValue[1];
}
}
}
}
//Ensure it is not still set from a previous upload.
mCameraFilePath = null;
if (mimeType.equals(imageMimeType)) {
if (mediaSource.equals(mediaSourceValueCamera)) {
// Specified 'image/*' and requested the camera, so go ahead and launch the
// camera directly.
startActivity(createCameraIntent());
return;
} else {
// Specified just 'image/*', capture=filesystem, or an invalid capture parameter.
// In all these cases we show a traditional picker filetered on accept type
// so launch an intent for both the Camera and image/* OPENABLE.
Intent chooser = createChooserIntent(createCameraIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(imageMimeType));
startActivity(chooser);
return;
}
} else if (mimeType.equals(videoMimeType)) {
if (mediaSource.equals(mediaSourceValueCamcorder)) {
// Specified 'video/*' and requested the camcorder, so go ahead and launch the
// camcorder directly.
startActivity(createCamcorderIntent());
return;
} else {
// Specified just 'video/*', capture=filesystem or an invalid capture parameter.
// In all these cases we show an intent for the traditional file picker, filtered
// on accept type so launch an intent for both camcorder and video/* OPENABLE.
Intent chooser = createChooserIntent(createCamcorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(videoMimeType));
startActivity(chooser);
return;
}
} else if (mimeType.equals(audioMimeType)) {
if (mediaSource.equals(mediaSourceValueMicrophone)) {
// Specified 'audio/*' and requested microphone, so go ahead and launch the sound
// recorder.
startActivity(createSoundRecorderIntent());
return;
} else {
// Specified just 'audio/*', capture=filesystem of an invalid capture parameter.
// In all these cases so go ahead and launch an intent for both the sound
// recorder and audio/* OPENABLE.
Intent chooser = createChooserIntent(createSoundRecorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(audioMimeType));
startActivity(chooser);
return;
}
}
// No special handling based on the accept type was necessary, so trigger the default
// file upload chooser.
startActivity(createDefaultOpenableIntent());
}
private void startActivity(Intent intent) {
try {
mController.getActivity().startActivityForResult(intent, Controller.FILE_SELECTED);
} catch (ActivityNotFoundException e) {
// No installed app was able to handle the intent that
// we sent, so fallback to the default file upload control.
try {
mCaughtActivityNotFoundException = true;
mController.getActivity().startActivityForResult(createDefaultOpenableIntent(),
Controller.FILE_SELECTED);
} catch (ActivityNotFoundException e2) {
// Nothing can return us a file, so file upload is effectively disabled.
Toast.makeText(mController.getActivity(), R.string.uploads_disabled,
Toast.LENGTH_LONG).show();
}
}
}
private Intent createDefaultOpenableIntent() {
// Create and return a chooser with the default OPENABLE
// actions including the camera, camcorder and sound
// recorder where available.
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("*/*");
Intent chooser = createChooserIntent(createCameraIntent(), createCamcorderIntent(),
createSoundRecorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, i);
return chooser;
}
private Intent createChooserIntent(Intent... intents) {
Intent chooser = new Intent(Intent.ACTION_CHOOSER);
chooser.putExtra(Intent.EXTRA_INITIAL_INTENTS, intents);
chooser.putExtra(Intent.EXTRA_TITLE,
mController.getActivity().getResources()
.getString(R.string.choose_upload));
return chooser;
}
private Intent createOpenableIntent(String type) {
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType(type);
return i;
}
private Intent createCameraIntent() {
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File externalDataDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DCIM);
File cameraDataDir = new File(externalDataDir.getAbsolutePath() +
File.separator + "browser-photos");
cameraDataDir.mkdirs();
mCameraFilePath = cameraDataDir.getAbsolutePath() + File.separator +
System.currentTimeMillis() + ".jpg";
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(mCameraFilePath)));
return cameraIntent;
}
private Intent createCamcorderIntent() {
return new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
}
private Intent createSoundRecorderIntent() {
return new Intent(MediaStore.Audio.Media.RECORD_SOUND_ACTION);
}
public void onPageFinished(WebView view, String url) {
// Removes Progress Bar
findViewById(R.id.progressbar).setVisibility(View.GONE);
// Adds Cookies. Yummy!
CookieSyncManager.getInstance().sync();
}
}
@Override
public void onBackPressed() {
// Enables going back history
if (webView.copyBackForwardList().getCurrentIndex() > 0) {
webView.goBack();
}
else {
// Your exit alert code, or alternatively line below to finish
// Finishes forum activity
super.onBackPressed();
}
}
}
这是 logcat 数据：
12 - 18 03: 12: 53.095 28851 - 28851 / com.technologx.technologx E / AndroidRuntime: FATAL EXCEPTION:
main
Process: com.technologx.technologx, PID: 28851
java.lang.RuntimeException: Unable to start activity ComponentInfo {
com.technologx.technologx / com.technologx.technologx.MainActivity
}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)'
on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2379)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2441)
at android.app.ActivityThread.access0(ActivityThread.java: 162)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1349)
at android.os.Handler.dispatchMessage(Handler.java: 102)
at android.os.Looper.loop(Looper.java: 135)
at android.app.ActivityThread.main(ActivityThread.java: 5431)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java: 372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 914)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 707)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)'
on a null object reference
at com.technologx.technologx.MainActivity.onCreate(MainActivity.java: 47)
at android.app.Activity.performCreate(Activity.java: 6056)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java: 1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2332)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2441)
at android.app.ActivityThread.access0(ActivityThread.java: 162)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1349)
at android.os.Handler.dispatchMessage(Handler.java: 102)
at android.os.Looper.loop(Looper.java: 135)
at android.app.ActivityThread.main(ActivityThread.java: 5431)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java: 372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 914)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 707)
注意我不是 Java 程序员。虽然猜测，当您声明它时，它将是一个空对象引用：
private WebView webView;
因此在这两行中，您尝试对这个（空）对象做一些事情，然后将该对象设置为一个实例（可能不为空）：
webView.setWebViewClient(new WebViewClient());
webView = (WebView) findViewById(R.id.activity_main_webview);
这与你的错误一致：
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)'
on a null object reference
一个为空的对象根本不是一个真正的对象，它只是一个空，所以你不能对它执行操作。为什么不尝试交换最后两行，看看是否有帮助？
我正在尝试为我的论坛创建一个应用程序，这样用户就不必在他们的移动设备上使用浏览器或使用其他应用程序。我 运行 现在正在处理应用程序崩溃的问题，但不确定原因。我是这方面的新手，所以当涉及到代码错误时，我真的不知道该寻找什么，也许我可以得到一些帮助来找出我做错了什么？
我可能需要更改代码中的某些内容，请随时告诉我，但请告诉我需要更改哪些内容才能取悦。我还需要弄清楚如何向应用程序添加复制和粘贴功能以及让应用程序为 "remember me".
设置 cookie 的能力package com.technologx.technologx;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.DownloadManager;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.view.Window;
import android.webkit.CookieSyncManager;
import android.webkit.JsResult;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebSettings.PluginState;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.io.File;
import java.lang.reflect.Method;
import java.net.URL;
public class MainActivity extends Activity {
private WebView webView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Adds Progress Bar Support
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
// Makes Progress Bar Visible
getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
// Use forum.xml as webview layout
setContentView(R.layout.activity_main);
webView.setWebViewClient(new WebViewClient());
webView = (WebView) findViewById(R.id.activity_main_webview);
webView.getSettings().setJavaScriptEnabled(true);
// Adds Zoom Control (You may not need this)
webView.getSettings().setSupportZoom(true);
// Enables Multi-Touch. if supported by ROM
webView.getSettings().setBuiltInZoomControls(true);
initWebView(webView);
webView.loadUrl("https://technologx.com"); // TODO input your url
// This will handle downloading. It requires Gingerbread, though
final DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
// This is where downloaded files will be written, using the package name isn't required
// but it's a good way to communicate who owns the directory
final File destinationDir = new File (Environment.getExternalStorageDirectory(), getPackageName());
if (!destinationDir.exists()) {
destinationDir.mkdir(); // Don't forget to make the directory if it's not there
}
webView.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading (WebView view, String url) {
boolean shouldOverride = false;
// We only want to handle requests for mp3 files, everything else the webview
// can handle normally
if (url.endsWith(".zip")) {
shouldOverride = true;
Uri source = Uri.parse(url);
// Make a new request pointing to the mp3 url
DownloadManager.Request request = new DownloadManager.Request(source);
// Use the same file name for the destination
File destinationFile = new File (destinationDir, source.getLastPathSegment());
request.setDestinationUri(Uri.fromFile(destinationFile));
// Add it to the manager
manager.enqueue(request);
}
return shouldOverride;
}
});
}
private final static Object methodInvoke(Object obj, String method, Class<?>[] parameterTypes, Object[] args) {
try {
Method m = obj.getClass().getMethod(method, new Class[] { boolean.class });
m.invoke(obj, args);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private void initWebView(WebView webView) {
WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setAllowFileAccess(true);
settings.setDomStorageEnabled(true);
settings.setCacheMode(WebSettings.LOAD_NO_CACHE);
settings.setLoadWithOverviewMode(true);
settings.setUseWideViewPort(true);
settings.setSupportZoom(true);
// settings.setPluginsEnabled(true);
methodInvoke(settings, "setPluginsEnabled", new Class[] { boolean.class }, new Object[] { true });
// settings.setPluginState(PluginState.ON);
methodInvoke(settings, "setPluginState", new Class[] { PluginState.class }, new Object[] { PluginState.ON });
// settings.setPluginsEnabled(true);
methodInvoke(settings, "setPluginsEnabled", new Class[] { boolean.class }, new Object[] { true });
// settings.setAllowUniversalAccessFromFileURLs(true);
methodInvoke(settings, "setAllowUniversalAccessFromFileURLs", new Class[] { boolean.class }, new Object[] { true });
// settings.setAllowFileAccessFromFileURLs(true);
methodInvoke(settings, "setAllowFileAccessFromFileURLs", new Class[] { boolean.class }, new Object[] { true });
webView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
webView.clearHistory();
webView.clearFormData();
webView.clearCache(true);
webView.setWebChromeClient(new MyWebChromeClient());
// webView.setDownloadListener(downloadListener);
}
UploadHandler mUploadHandler;
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == Controller.FILE_SELECTED) {
// Chose a file from the file picker.
if (mUploadHandler != null) {
mUploadHandler.onResult(resultCode, intent);
}
}
super.onActivityResult(requestCode, resultCode, intent);
}
class MyWebChromeClient extends WebChromeClient {
public MyWebChromeClient() {
}
private String getTitleFromUrl(String url) {
String title = url;
try {
URL urlObj = new URL(url);
String host = urlObj.getHost();
if (host != null && !host.isEmpty()) {
return urlObj.getProtocol() + "://" + host;
}
if (url.startsWith("file:")) {
String fileName = urlObj.getFile();
if (fileName != null && !fileName.isEmpty()) {
return fileName;
}
}
} catch (Exception e) {
// ignore
}
return title;
}
@Override
public boolean onJsAlert(WebView view, String url, String message, final JsResult result) {
String newTitle = getTitleFromUrl(url);
new AlertDialog.Builder(MainActivity.this).setTitle(newTitle).setMessage(message).setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
result.confirm();
}
}).setCancelable(false).create().show();
return true;
// return super.onJsAlert(view, url, message, result);
}
@Override
public boolean onJsConfirm(WebView view, String url, String message, final JsResult result) {
String newTitle = getTitleFromUrl(url);
new AlertDialog.Builder(MainActivity.this).setTitle(newTitle).setMessage(message).setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
result.confirm();
}
}).setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
result.cancel();
}
}).setCancelable(false).create().show();
return true;
// return super.onJsConfirm(view, url, message, result);
}
// Android 2.x
public void openFileChooser(ValueCallback<Uri> uploadMsg) {
openFileChooser(uploadMsg, "");
}
// Android 3.0
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
openFileChooser(uploadMsg, "", "filesystem");
}
// Android 4.1
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
mUploadHandler = new UploadHandler(new Controller());
mUploadHandler.openFileChooser(uploadMsg, acceptType, capture);
}
// Android 4.4, 4.4.1, 4.4.2
// openFileChooser function is not called on Android 4.4, 4.4.1, 4.4.2,
// you may use your own java script interface or other hybrid framework.
// Android 5.0.1
public boolean onShowFileChooser(
WebView webView, ValueCallback<Uri[]> filePathCallback,
FileChooserParams fileChooserParams) {
String acceptTypes[] = fileChooserParams.getAcceptTypes();
String acceptType = "";
for (int i = 0; i < acceptTypes.length; ++ i) {
if (acceptTypes[i] != null && acceptTypes[i].length() != 0)
acceptType += acceptTypes[i] + ";";
}
if (acceptType.length() == 0)
acceptType = "*/*";
final ValueCallback<Uri[]> finalFilePathCallback = filePathCallback;
ValueCallback<Uri> vc = new ValueCallback<Uri>() {
@Override
public void onReceiveValue(Uri value) {
Uri[] result;
if (value != null)
result = new Uri[]{value};
else
result = null;
finalFilePathCallback.onReceiveValue(result);
}
};
openFileChooser(vc, acceptType, "filesystem");
return true;
}
};
class Controller {
final static int FILE_SELECTED = 4;
Activity getActivity() {
return MainActivity.this;
}
}
// public class UploadHandler {
class UploadHandler {
/*
* The Object used to inform the WebView of the file to upload.
*/
private ValueCallback<Uri> mUploadMessage;
private String mCameraFilePath;
private boolean mHandled;
private boolean mCaughtActivityNotFoundException;
private Controller mController;
public UploadHandler(Controller controller) {
mController = controller;
}
String getFilePath() {
return mCameraFilePath;
}
boolean handled() {
return mHandled;
}
void onResult(int resultCode, Intent intent) {
if (resultCode == Activity.RESULT_CANCELED && mCaughtActivityNotFoundException) {
// Couldn't resolve an activity, we are going to try again so skip
// this result.
mCaughtActivityNotFoundException = false;
return;
}
Uri result = intent == null || resultCode != Activity.RESULT_OK ? null
: intent.getData();
// As we ask the camera to save the result of the user taking
// a picture, the camera application does not return anything other
// than RESULT_OK. So we need to check whether the file we expected
// was written to disk in the in the case that we
// did not get an intent returned but did get a RESULT_OK. If it was,
// we assume that this result has came back from the camera.
if (result == null && intent == null && resultCode == Activity.RESULT_OK) {
File cameraFile = new File(mCameraFilePath);
if (cameraFile.exists()) {
result = Uri.fromFile(cameraFile);
// Broadcast to the media scanner that we have a new photo
// so it will be added into the gallery for the user.
mController.getActivity().sendBroadcast(
new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, result));
}
}
mUploadMessage.onReceiveValue(result);
mHandled = true;
mCaughtActivityNotFoundException = false;
}
void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
final String imageMimeType = "image/*";
final String videoMimeType = "video/*";
final String audioMimeType = "audio/*";
final String mediaSourceKey = "capture";
final String mediaSourceValueCamera = "camera";
final String mediaSourceValueFileSystem = "filesystem";
final String mediaSourceValueCamcorder = "camcorder";
final String mediaSourceValueMicrophone = "microphone";
// According to the spec, media source can be 'filesystem' or 'camera' or 'camcorder'
// or 'microphone' and the default value should be 'filesystem'.
String mediaSource = mediaSourceValueFileSystem;
if (mUploadMessage != null) {
// Already a file picker operation in progress.
return;
}
mUploadMessage = uploadMsg;
// Parse the accept type.
String params[] = acceptType.split(";");
String mimeType = params[0];
if (capture.length() > 0) {
mediaSource = capture;
}
if (capture.equals(mediaSourceValueFileSystem)) {
// To maintain backwards compatibility with the previous implementation
// of the media capture API, if the value of the 'capture' attribute is
// "filesystem", we should examine the accept-type for a MIME type that
// may specify a different capture value.
for (String p : params) {
String[] keyValue = p.split("=");
if (keyValue.length == 2) {
// Process key=value parameters.
if (mediaSourceKey.equals(keyValue[0])) {
mediaSource = keyValue[1];
}
}
}
}
//Ensure it is not still set from a previous upload.
mCameraFilePath = null;
if (mimeType.equals(imageMimeType)) {
if (mediaSource.equals(mediaSourceValueCamera)) {
// Specified 'image/*' and requested the camera, so go ahead and launch the
// camera directly.
startActivity(createCameraIntent());
return;
} else {
// Specified just 'image/*', capture=filesystem, or an invalid capture parameter.
// In all these cases we show a traditional picker filetered on accept type
// so launch an intent for both the Camera and image/* OPENABLE.
Intent chooser = createChooserIntent(createCameraIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(imageMimeType));
startActivity(chooser);
return;
}
} else if (mimeType.equals(videoMimeType)) {
if (mediaSource.equals(mediaSourceValueCamcorder)) {
// Specified 'video/*' and requested the camcorder, so go ahead and launch the
// camcorder directly.
startActivity(createCamcorderIntent());
return;
} else {
// Specified just 'video/*', capture=filesystem or an invalid capture parameter.
// In all these cases we show an intent for the traditional file picker, filtered
// on accept type so launch an intent for both camcorder and video/* OPENABLE.
Intent chooser = createChooserIntent(createCamcorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(videoMimeType));
startActivity(chooser);
return;
}
} else if (mimeType.equals(audioMimeType)) {
if (mediaSource.equals(mediaSourceValueMicrophone)) {
// Specified 'audio/*' and requested microphone, so go ahead and launch the sound
// recorder.
startActivity(createSoundRecorderIntent());
return;
} else {
// Specified just 'audio/*', capture=filesystem of an invalid capture parameter.
// In all these cases so go ahead and launch an intent for both the sound
// recorder and audio/* OPENABLE.
Intent chooser = createChooserIntent(createSoundRecorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, createOpenableIntent(audioMimeType));
startActivity(chooser);
return;
}
}
// No special handling based on the accept type was necessary, so trigger the default
// file upload chooser.
startActivity(createDefaultOpenableIntent());
}
private void startActivity(Intent intent) {
try {
mController.getActivity().startActivityForResult(intent, Controller.FILE_SELECTED);
} catch (ActivityNotFoundException e) {
// No installed app was able to handle the intent that
// we sent, so fallback to the default file upload control.
try {
mCaughtActivityNotFoundException = true;
mController.getActivity().startActivityForResult(createDefaultOpenableIntent(),
Controller.FILE_SELECTED);
} catch (ActivityNotFoundException e2) {
// Nothing can return us a file, so file upload is effectively disabled.
Toast.makeText(mController.getActivity(), R.string.uploads_disabled,
Toast.LENGTH_LONG).show();
}
}
}
private Intent createDefaultOpenableIntent() {
// Create and return a chooser with the default OPENABLE
// actions including the camera, camcorder and sound
// recorder where available.
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType("*/*");
Intent chooser = createChooserIntent(createCameraIntent(), createCamcorderIntent(),
createSoundRecorderIntent());
chooser.putExtra(Intent.EXTRA_INTENT, i);
return chooser;
}
private Intent createChooserIntent(Intent... intents) {
Intent chooser = new Intent(Intent.ACTION_CHOOSER);
chooser.putExtra(Intent.EXTRA_INITIAL_INTENTS, intents);
chooser.putExtra(Intent.EXTRA_TITLE,
mController.getActivity().getResources()
.getString(R.string.choose_upload));
return chooser;
}
private Intent createOpenableIntent(String type) {
Intent i = new Intent(Intent.ACTION_GET_CONTENT);
i.addCategory(Intent.CATEGORY_OPENABLE);
i.setType(type);
return i;
}
private Intent createCameraIntent() {
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File externalDataDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DCIM);
File cameraDataDir = new File(externalDataDir.getAbsolutePath() +
File.separator + "browser-photos");
cameraDataDir.mkdirs();
mCameraFilePath = cameraDataDir.getAbsolutePath() + File.separator +
System.currentTimeMillis() + ".jpg";
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(mCameraFilePath)));
return cameraIntent;
}
private Intent createCamcorderIntent() {
return new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
}
private Intent createSoundRecorderIntent() {
return new Intent(MediaStore.Audio.Media.RECORD_SOUND_ACTION);
}
public void onPageFinished(WebView view, String url) {
// Removes Progress Bar
findViewById(R.id.progressbar).setVisibility(View.GONE);
// Adds Cookies. Yummy!
CookieSyncManager.getInstance().sync();
}
}
@Override
public void onBackPressed() {
// Enables going back history
if (webView.copyBackForwardList().getCurrentIndex() > 0) {
webView.goBack();
}
else {
// Your exit alert code, or alternatively line below to finish
// Finishes forum activity
super.onBackPressed();
}
}
}
这是 logcat 数据：
12 - 18 03: 12: 53.095 28851 - 28851 / com.technologx.technologx E / AndroidRuntime: FATAL EXCEPTION:
main
Process: com.technologx.technologx, PID: 28851
java.lang.RuntimeException: Unable to start activity ComponentInfo {
com.technologx.technologx / com.technologx.technologx.MainActivity
}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)'
on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2379)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2441)
at android.app.ActivityThread.access0(ActivityThread.java: 162)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1349)
at android.os.Handler.dispatchMessage(Handler.java: 102)
at android.os.Looper.loop(Looper.java: 135)
at android.app.ActivityThread.main(ActivityThread.java: 5431)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java: 372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 914)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 707)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)'
on a null object reference
at com.technologx.technologx.MainActivity.onCreate(MainActivity.java: 47)
at android.app.Activity.performCreate(Activity.java: 6056)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java: 1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2332)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2441)
at android.app.ActivityThread.access0(ActivityThread.java: 162)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1349)
at android.os.Handler.dispatchMessage(Handler.java: 102)
at android.os.Looper.loop(Looper.java: 135)
at android.app.ActivityThread.main(ActivityThread.java: 5431)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java: 372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 914)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 707)
注意我不是 Java 程序员。虽然猜测，当您声明它时，它将是一个空对象引用：
private WebView webView;
因此在这两行中，您尝试对这个（空）对象做一些事情，然后将该对象设置为一个实例（可能不为空）：
webView.setWebViewClient(new WebViewClient());
webView = (WebView) findViewById(R.id.activity_main_webview);
这与你的错误一致：
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebViewClient(android.webkit.WebViewClient)' on a null object reference
一个为空的对象根本不是一个真正的对象，它只是一个空，所以你不能对它执行操作。为什么不尝试交换最后两行，看看是否有帮助？