Android WebView：ProgressBar 未显示（使用 Google 的教程）
Android WebView: ProgressBar not showing (Used Google's tutorial)
在 WebView 中加载网页时不显示进度条。我的 XML 代码片段：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity" >
<ProgressBar
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/progressBar"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<WebView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/webView"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
我的 MainActivity.java 代码片段：
public class Main1Activity extends ActionBarActivity
{
private WebView webView;
public void onCreate( Bundle savedInstanceState) {
getWindow().requestFeature(Window.FEATURE_PROGRESS);
super.onCreate(savedInstanceState);
webView = new WebView(this);
setContentView(webView);
webView.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress with different scales.
// The progress meter will automatically disappear when we reach 100%
activity.setProgress(progress * 100);
}
});
webView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webView.loadUrl("http://developer.android.com/");
}
// Go back to previous upon clicking back button
// instead of closing app.
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack())
{
webView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}
}
我已经检查了 Whosebug 上与此相关的所有资源并发布了这个，因为我没有找到任何解决方案。起初这应该是非常容易的，但是这已经花费了 5 天多的时间并且还在增加。
我认为您正在尝试混合 2 种不同的 ProgressBar 实现，第一种使用 getWindow().requestFeature(Window.FEATURE_PROGRESS);，第二种使用定义到主布局中的 ProgressBar。我认为最好的选择是在布局中使用 ProgressBar。
因此您需要稍微更改一下代码，使用 onPageStarted() 显示 ProgressBar 并使用 onPageFinished() 隐藏它：
public class MainActivity extends ActionBarActivity
{
private WebView webView;
private ProgressBar progressBar;
public void onCreate( Bundle savedInstanceState) {
//getWindow().requestFeature(Window.FEATURE_PROGRESS); // You don´t need this!
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = (ProgressBar)findViewById(R.id.progressBar);
/*webView = new WebView(this);
setContentView(webView);*/ //Using this your WebView was covering all your screen :P!
webView = (WebView)findViewById(R.id.webView);//Use the WebView defined in your layout.
webView.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress with different scales.
// The progress meter will automatically disappear when we reach 100%
activity.setProgress(progress * 100);
}
});
webView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
progressBar.setVisibility(View.VISIBLE);
super.onPageStarted(view, url, favicon);
}
@Override
public void onPageFinished(WebView view, String url) {
progressBar.setVisibility(View.INVISIBLE);
super.onPageFinished(view, url);
}
});
webView.loadUrl("http://developer.android.com/");
}
// Go back to previous upon clicking back button
// instead of closing app.
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack())
{
webView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}
}
并且您的布局也发生了一些变化：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:indeterminate="true"
android:visibility="visible" />
<WebView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/webView"
android:layout_below="@+id/progressBar"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
5 天，还在继续？不可能:)
在 WebView 中加载网页时不显示进度条。我的 XML 代码片段：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity" >
<ProgressBar
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/progressBar"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<WebView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/webView"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
我的 MainActivity.java 代码片段：
public class Main1Activity extends ActionBarActivity
{
private WebView webView;
public void onCreate( Bundle savedInstanceState) {
getWindow().requestFeature(Window.FEATURE_PROGRESS);
super.onCreate(savedInstanceState);
webView = new WebView(this);
setContentView(webView);
webView.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress with different scales.
// The progress meter will automatically disappear when we reach 100%
activity.setProgress(progress * 100);
}
});
webView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
});
webView.loadUrl("http://developer.android.com/");
}
// Go back to previous upon clicking back button
// instead of closing app.
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack())
{
webView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}
}
我已经检查了 Whosebug 上与此相关的所有资源并发布了这个，因为我没有找到任何解决方案。起初这应该是非常容易的，但是这已经花费了 5 天多的时间并且还在增加。
我认为您正在尝试混合 2 种不同的 ProgressBar 实现，第一种使用 getWindow().requestFeature(Window.FEATURE_PROGRESS);，第二种使用定义到主布局中的 ProgressBar。我认为最好的选择是在布局中使用 ProgressBar。
因此您需要稍微更改一下代码，使用 onPageStarted() 显示 ProgressBar 并使用 onPageFinished() 隐藏它：
public class MainActivity extends ActionBarActivity
{
private WebView webView;
private ProgressBar progressBar;
public void onCreate( Bundle savedInstanceState) {
//getWindow().requestFeature(Window.FEATURE_PROGRESS); // You don´t need this!
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = (ProgressBar)findViewById(R.id.progressBar);
/*webView = new WebView(this);
setContentView(webView);*/ //Using this your WebView was covering all your screen :P!
webView = (WebView)findViewById(R.id.webView);//Use the WebView defined in your layout.
webView.getSettings().setJavaScriptEnabled(true);
final Activity activity = this;
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
// Activities and WebViews measure progress with different scales.
// The progress meter will automatically disappear when we reach 100%
activity.setProgress(progress * 100);
}
});
webView.setWebViewClient(new WebViewClient() {
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
progressBar.setVisibility(View.VISIBLE);
super.onPageStarted(view, url, favicon);
}
@Override
public void onPageFinished(WebView view, String url) {
progressBar.setVisibility(View.INVISIBLE);
super.onPageFinished(view, url);
}
});
webView.loadUrl("http://developer.android.com/");
}
// Go back to previous upon clicking back button
// instead of closing app.
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack())
{
webView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}
}
并且您的布局也发生了一些变化：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:indeterminate="true"
android:visibility="visible" />
<WebView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/webView"
android:layout_below="@+id/progressBar"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
5 天，还在继续？不可能:)