Android 在 AsyncTask 中崩溃
Android crash in AsyncTask
当我 运行 我的项目和 activity 的 运行 AsyncTask 显示项目的所有内容时，APP 崩溃显示以下错误消息：
06-17 20:56:52.856 418-428/? E/art﹕ Failed sending reply to debugger: Broken pipe
06-17 20:57:07.391 418-767/com.example.user.project_test E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #3
Process: com.example.user.project_test, PID: 418
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:304)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6357)
at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:909)
at android.view.ViewGroup.invalidateChild(ViewGroup.java:4690)
at android.view.View.invalidateInternal(View.java:11801)
at android.view.View.invalidate(View.java:11765)
at android.view.View.invalidate(View.java:11749)
at android.widget.TextView.checkForRelayout(TextView.java:6858)
at android.widget.TextView.setText(TextView.java:4057)
at android.widget.TextView.setText(TextView.java:3915)
at android.widget.TextView.setText(TextView.java:3890)
at com.example.user.project.itemActivity$getitem.doInBackground(itemActivity.java:132)
at com.example.user.project.itemActivity$getitem.doInBackground(itemActivity.java:84)
at android.os.AsyncTask.call(AsyncTask.java:292)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
06-17 20:57:07.612 418-418/com.example.user.project_test E/WindowManager﹕ android.view.WindowLeaked: Activity com.example.user.project.itemActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{19feb64d V.E..... R......D 0,0-1026,348} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:363)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:271)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
at android.app.Dialog.show(Dialog.java:298)
at com.example.user.project.itemActivity$getitem.onPreExecute(itemActivity.java:96)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:591)
at android.os.AsyncTask.execute(AsyncTask.java:539)
at com.example.user.project.itemActivity.onCreate(itemActivity.java:71)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.description.invoke(Native description)
at java.lang.reflect.description.invoke(description.java:372)
at com.android.internal.os.ZygoteInit$descriptionAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我把我当前的代码放在这里
ItemActivity.java（这是在 AsyncTask 中崩溃的 class：
public class ItemActivity extends AppCompatActivity {
private static final String TAG_SUCCESS = "success";
private static final String TAG_ITEM = "item";
private static final String TAG_ITEM_NAME = "name";
private static final String TAG_ITEM_description = "item";
Integer item_id;
String name;
String username;
String item;
TextView itemname;
TextView itemitem;
ProgressDialog pDialog;
JSONParser jParser;
RecyclerView recycler;
ActionBar actionBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
Intent i = getIntent();
if (i.hasExtra("item_id")) {
Bundle bd = getIntent().getExtras();
/*if ((!bd.getString("name").equals(null) || bd.getString("name").trim().length() > 0) && (!bd.getString("username").equals(null) || bd.getString("username").trim().length() > 0) && (!bd.getString("description").equals(null) || bd.getString("description").trim().length() > 0)) {
name = bd.getString("name");
username = bd.getString("username");
description = bd.getString("description");
}*/
item_id = bd.getInt("item_id");
}
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
actionBar = getSupportActionBar();
actionBar.setTitle(R.string.app_name);
itemname = (TextView) findViewById(R.id.itemName);
itemdescription = (TextView) findViewById(R.id.itemDescription);
new getitem().execute();
/*recycler = (RecyclerView) findViewById(R.id.recycler);
recycler.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recycler.setLayoutManager(layoutManager);*/
}
/**
* Background Async Task to Get complete item details
*/
class getitem extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
*/
@Override
protected void onPreExecute() {
super.onPreExecute();
if (pDialog != null) {
pDialog = null;
}
pDialog = new ProgressDialog(itemActivity.this);
pDialog.setMessage(getResources().getString(R.string.loadingitem));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* Getting item details in background thread
*/
protected String doInBackground(String... params) {
// updating UI from Background Thread
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> myParameters = new ArrayList<NameValuePair>();
myParameters.add(new BasicNameValuePair("item_id", Integer.toString(item_id)));
// getting item details by making HTTP request
// Note that item details url will use GET request
jParser = new JSONParser();
JSONObject json = jParser.makeHttpRequest(AppConfig.URL_GET_item, "GET", myParameters);
// check your log for json response
Log.d("Single item Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received item details
JSONArray itemObj = json.getJSONArray(TAG_item); // JSON Array
// get first item object from JSON Array
JSONObject item = itemObj.getJSONObject(0);
// item with this pid found
// Edit Text
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
} else {
// item with pid not found
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* *
*/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
/*itemname=(TextView)
findViewById(R.id.itemName);
itemdescription=(TextView)
findViewById(R.id.itemdescription);*/
//itemname.setText(name);
//itemdescription.setText(description);
}
activity_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/navigation_drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="@bool/fitsSystemWindows">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="@dimen/status_bar_height"
android:background="?colorPrimary" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="@dimen/status_bar_height"
android:background="?colorPrimaryDark" />
</LinearLayout>
<FrameLayout
android:id="@+id/flma"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/status_bar_height">
<TextView
android:id="@+id/itemName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|top"
android:layout_marginTop="80dp"
android:gravity="center"
android:textAllCaps="true"
android:textSize="25dp"
android:textStyle="bold" />
<ImageView
android:id="@+id/itemPhoto"
android:layout_width="fill_parent"
android:layout_height="300dp"
android:layout_gravity="center"
android:background="#000"
android:src="@drawable/header" />
<TextView
android:id="@+id/itemdescription"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|bottom"
android:layout_marginBottom="50dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</FrameLayout>
<android.support.design.widget.NavigationView
android:id="@+id/navigation_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="@bool/fitsSystemWindows"
app:headerLayout="@layout/navigation_drawer_header"
app:menu="@menu/navigation_drawer_menu"
app:theme="@style/NavigationViewTheme" />
</android.support.v4.widget.DrawerLayout>
我正在搜索，我发现检查进度对话框是否不为 null 将其设置为 null 问题可以解决，但对我不起作用。
有谁知道我的 class 中是否有误？
谢谢！！
解决方案：
感谢 Itzik Samara 和 ligi 对问题的帮助和解释，我解决了这个问题，删除了 Itzik Samara 指示的行并在 onPostExecute 中添加了以下代码：
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
try {
itemname.setText(item.getString(TAG_item_NAME));
} catch (JSONException e) {
e.printStackTrace();
}
try {
itemdescription.setText(item.getString(TAG_item_description));
} catch (JSONException e) {
e.printStackTrace();
}
pDialog.dismiss();
}
你不能触及后台线程中的 UI 元素（比如 setText） UI 线程）并阅读有关 android 线程
你的问题是那两行：
itemname.setText(item.getString(TAG_ITEM_NAME));
itemdescription.setText(item.getString(TAG_ITEM_DESCRIPTION));
2 个选择：
- 将数据发送到
onPostExecute 并从那里更新 EditText
- 使用
RunOnUiThread并更新里面的2个EditText
尝试将此添加到您的 doInBackground()
runOnUiThread(new Runnable() {
@Override
public void run() {
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
}
});
或者把这两行放在onPostExecute()
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
这是你的全部 Class
public class itemActivity extends AppCompatActivity {
private static final String TAG_SUCCESS = "success";
private static final String TAG_item = "item";
private static final String TAG_item_NAME = "name";
private static final String TAG_item_description = "description";
Integer item_id;
String name;
String username;
String description;
TextView itemname;
TextView itemdescription;
ProgressDialog pDialog;
JSONParser jParser;
RecyclerView recycler;
ActionBar actionBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
Intent i = getIntent();
if (i.hasExtra("item_id")) {
Bundle bd = getIntent().getExtras();
/*if ((!bd.getString("name").equals(null) || bd.getString("name").trim().length() > 0) && (!bd.getString("username").equals(null) || bd.getString("username").trim().length() > 0) && (!bd.getString("description").equals(null) || bd.getString("description").trim().length() > 0)) {
name = bd.getString("name");
username = bd.getString("username");
description = bd.getString("description");
}*/
item_id = bd.getInt("item_id");
}
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
actionBar = getSupportActionBar();
actionBar.setTitle(R.string.app_name);
itemname = (TextView) findViewById(R.id.itemName);
itemdescription = (TextView) findViewById(R.id.itemdescription);
new getitem().execute();
/*recycler = (RecyclerView) findViewById(R.id.recycler);
recycler.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recycler.setLayoutManager(layoutManager);*/
}
/**
* Background Async Task to Get complete item details
*/
class getitem extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
*/
@Override
protected void onPreExecute() {
super.onPreExecute();
if (pDialog != null) {
pDialog = null;
}
pDialog = new ProgressDialog(itemActivity.this);
pDialog.setMessage(getResources().getString(R.string.loadingitem));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* Getting item details in background thread
*/
protected String doInBackground(String... params) {
// updating UI from Background Thread
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> myParameters = new ArrayList<NameValuePair>();
myParameters.add(new BasicNameValuePair("item_id", Integer.toString(item_id)));
// getting item details by making HTTP request
// Note that item details url will use GET request
jParser = new JSONParser();
JSONObject json = jParser.makeHttpRequest(AppConfig.URL_GET_item, "GET", myParameters);
// check your log for json response
Log.d("Single item Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received item details
JSONArray itemObj = json.getJSONArray(TAG_item); // JSON Array
// get first item object from JSON Array
JSONObject item = itemObj.getJSONObject(0);
// item with this pid found
// Edit Text
runOnUiThread(new Runnable() {
@Override
public void run() {
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
}
});
} else {
// item with pid not found
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* *
*/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
}
当我 运行 我的项目和 activity 的 运行 AsyncTask 显示项目的所有内容时，APP 崩溃显示以下错误消息：
06-17 20:56:52.856 418-428/? E/art﹕ Failed sending reply to debugger: Broken pipe
06-17 20:57:07.391 418-767/com.example.user.project_test E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #3
Process: com.example.user.project_test, PID: 418
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:304)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6357)
at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:909)
at android.view.ViewGroup.invalidateChild(ViewGroup.java:4690)
at android.view.View.invalidateInternal(View.java:11801)
at android.view.View.invalidate(View.java:11765)
at android.view.View.invalidate(View.java:11749)
at android.widget.TextView.checkForRelayout(TextView.java:6858)
at android.widget.TextView.setText(TextView.java:4057)
at android.widget.TextView.setText(TextView.java:3915)
at android.widget.TextView.setText(TextView.java:3890)
at com.example.user.project.itemActivity$getitem.doInBackground(itemActivity.java:132)
at com.example.user.project.itemActivity$getitem.doInBackground(itemActivity.java:84)
at android.os.AsyncTask.call(AsyncTask.java:292)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
06-17 20:57:07.612 418-418/com.example.user.project_test E/WindowManager﹕ android.view.WindowLeaked: Activity com.example.user.project.itemActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{19feb64d V.E..... R......D 0,0-1026,348} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:363)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:271)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
at android.app.Dialog.show(Dialog.java:298)
at com.example.user.project.itemActivity$getitem.onPreExecute(itemActivity.java:96)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:591)
at android.os.AsyncTask.execute(AsyncTask.java:539)
at com.example.user.project.itemActivity.onCreate(itemActivity.java:71)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.description.invoke(Native description)
at java.lang.reflect.description.invoke(description.java:372)
at com.android.internal.os.ZygoteInit$descriptionAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我把我当前的代码放在这里
ItemActivity.java（这是在 AsyncTask 中崩溃的 class：
public class ItemActivity extends AppCompatActivity {
private static final String TAG_SUCCESS = "success";
private static final String TAG_ITEM = "item";
private static final String TAG_ITEM_NAME = "name";
private static final String TAG_ITEM_description = "item";
Integer item_id;
String name;
String username;
String item;
TextView itemname;
TextView itemitem;
ProgressDialog pDialog;
JSONParser jParser;
RecyclerView recycler;
ActionBar actionBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
Intent i = getIntent();
if (i.hasExtra("item_id")) {
Bundle bd = getIntent().getExtras();
/*if ((!bd.getString("name").equals(null) || bd.getString("name").trim().length() > 0) && (!bd.getString("username").equals(null) || bd.getString("username").trim().length() > 0) && (!bd.getString("description").equals(null) || bd.getString("description").trim().length() > 0)) {
name = bd.getString("name");
username = bd.getString("username");
description = bd.getString("description");
}*/
item_id = bd.getInt("item_id");
}
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
actionBar = getSupportActionBar();
actionBar.setTitle(R.string.app_name);
itemname = (TextView) findViewById(R.id.itemName);
itemdescription = (TextView) findViewById(R.id.itemDescription);
new getitem().execute();
/*recycler = (RecyclerView) findViewById(R.id.recycler);
recycler.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recycler.setLayoutManager(layoutManager);*/
}
/**
* Background Async Task to Get complete item details
*/
class getitem extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
*/
@Override
protected void onPreExecute() {
super.onPreExecute();
if (pDialog != null) {
pDialog = null;
}
pDialog = new ProgressDialog(itemActivity.this);
pDialog.setMessage(getResources().getString(R.string.loadingitem));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* Getting item details in background thread
*/
protected String doInBackground(String... params) {
// updating UI from Background Thread
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> myParameters = new ArrayList<NameValuePair>();
myParameters.add(new BasicNameValuePair("item_id", Integer.toString(item_id)));
// getting item details by making HTTP request
// Note that item details url will use GET request
jParser = new JSONParser();
JSONObject json = jParser.makeHttpRequest(AppConfig.URL_GET_item, "GET", myParameters);
// check your log for json response
Log.d("Single item Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received item details
JSONArray itemObj = json.getJSONArray(TAG_item); // JSON Array
// get first item object from JSON Array
JSONObject item = itemObj.getJSONObject(0);
// item with this pid found
// Edit Text
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
} else {
// item with pid not found
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* *
*/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
/*itemname=(TextView)
findViewById(R.id.itemName);
itemdescription=(TextView)
findViewById(R.id.itemdescription);*/
//itemname.setText(name);
//itemdescription.setText(description);
}
activity_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/navigation_drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="@bool/fitsSystemWindows">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="@dimen/status_bar_height"
android:background="?colorPrimary" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="@dimen/status_bar_height"
android:background="?colorPrimaryDark" />
</LinearLayout>
<FrameLayout
android:id="@+id/flma"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/status_bar_height">
<TextView
android:id="@+id/itemName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|top"
android:layout_marginTop="80dp"
android:gravity="center"
android:textAllCaps="true"
android:textSize="25dp"
android:textStyle="bold" />
<ImageView
android:id="@+id/itemPhoto"
android:layout_width="fill_parent"
android:layout_height="300dp"
android:layout_gravity="center"
android:background="#000"
android:src="@drawable/header" />
<TextView
android:id="@+id/itemdescription"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|bottom"
android:layout_marginBottom="50dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</FrameLayout>
<android.support.design.widget.NavigationView
android:id="@+id/navigation_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="@bool/fitsSystemWindows"
app:headerLayout="@layout/navigation_drawer_header"
app:menu="@menu/navigation_drawer_menu"
app:theme="@style/NavigationViewTheme" />
</android.support.v4.widget.DrawerLayout>
我正在搜索，我发现检查进度对话框是否不为 null 将其设置为 null 问题可以解决，但对我不起作用。
有谁知道我的 class 中是否有误？
谢谢！！
解决方案：
感谢 Itzik Samara 和 ligi 对问题的帮助和解释，我解决了这个问题，删除了 Itzik Samara 指示的行并在 onPostExecute 中添加了以下代码：
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
try {
itemname.setText(item.getString(TAG_item_NAME));
} catch (JSONException e) {
e.printStackTrace();
}
try {
itemdescription.setText(item.getString(TAG_item_description));
} catch (JSONException e) {
e.printStackTrace();
}
pDialog.dismiss();
}
你不能触及后台线程中的 UI 元素（比如 setText） UI 线程）并阅读有关 android 线程
你的问题是那两行：
itemname.setText(item.getString(TAG_ITEM_NAME));
itemdescription.setText(item.getString(TAG_ITEM_DESCRIPTION));
2 个选择：
- 将数据发送到
onPostExecute并从那里更新 EditText - 使用
RunOnUiThread并更新里面的2个EditText
尝试将此添加到您的 doInBackground()
runOnUiThread(new Runnable() {
@Override
public void run() {
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
}
});
或者把这两行放在onPostExecute()
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
这是你的全部 Class
public class itemActivity extends AppCompatActivity {
private static final String TAG_SUCCESS = "success";
private static final String TAG_item = "item";
private static final String TAG_item_NAME = "name";
private static final String TAG_item_description = "description";
Integer item_id;
String name;
String username;
String description;
TextView itemname;
TextView itemdescription;
ProgressDialog pDialog;
JSONParser jParser;
RecyclerView recycler;
ActionBar actionBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
Intent i = getIntent();
if (i.hasExtra("item_id")) {
Bundle bd = getIntent().getExtras();
/*if ((!bd.getString("name").equals(null) || bd.getString("name").trim().length() > 0) && (!bd.getString("username").equals(null) || bd.getString("username").trim().length() > 0) && (!bd.getString("description").equals(null) || bd.getString("description").trim().length() > 0)) {
name = bd.getString("name");
username = bd.getString("username");
description = bd.getString("description");
}*/
item_id = bd.getInt("item_id");
}
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
actionBar = getSupportActionBar();
actionBar.setTitle(R.string.app_name);
itemname = (TextView) findViewById(R.id.itemName);
itemdescription = (TextView) findViewById(R.id.itemdescription);
new getitem().execute();
/*recycler = (RecyclerView) findViewById(R.id.recycler);
recycler.setHasFixedSize(true);
LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recycler.setLayoutManager(layoutManager);*/
}
/**
* Background Async Task to Get complete item details
*/
class getitem extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
*/
@Override
protected void onPreExecute() {
super.onPreExecute();
if (pDialog != null) {
pDialog = null;
}
pDialog = new ProgressDialog(itemActivity.this);
pDialog.setMessage(getResources().getString(R.string.loadingitem));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* Getting item details in background thread
*/
protected String doInBackground(String... params) {
// updating UI from Background Thread
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> myParameters = new ArrayList<NameValuePair>();
myParameters.add(new BasicNameValuePair("item_id", Integer.toString(item_id)));
// getting item details by making HTTP request
// Note that item details url will use GET request
jParser = new JSONParser();
JSONObject json = jParser.makeHttpRequest(AppConfig.URL_GET_item, "GET", myParameters);
// check your log for json response
Log.d("Single item Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received item details
JSONArray itemObj = json.getJSONArray(TAG_item); // JSON Array
// get first item object from JSON Array
JSONObject item = itemObj.getJSONObject(0);
// item with this pid found
// Edit Text
runOnUiThread(new Runnable() {
@Override
public void run() {
itemname.setText(item.getString(TAG_item_NAME));
itemdescription.setText(item.getString(TAG_item_description));
}
});
} else {
// item with pid not found
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* *
*/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
}