我有一个按下按钮的类，它显示一个对话框。这个盒子有两个按钮YES，NO。当我单击是时，我想调用异步任务来更新数据库中的某些值。我试过这个，但它给了我Looper.prepare（）错误。搜索了所有SO和GOogle，但没有解决方案。 any1有什么想法吗？
感谢名单
bttnSync.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
if (isOnline()) {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
MainPage.this);
alertDialogBuilder.setTitle("Syncing all data....!!");
alertDialogBuilder
.setMessage(
"Are you sure you want to Sync all the data?")
.setCancelable(false)
.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(
DialogInterface dialog, int id) {
//call();
new CountDownTask().execute();
MainPage.this.finish();
Intent i = new Intent(
"com.example.collegesoft.MainPage");
startActivity(i);
}
})
.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(
DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
} else {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
MainPage.this);
alertDialogBuilder.setTitle("No Internet Connection!!");
alertDialogBuilder
.setMessage(
"Device is not connected to the Internet or the connection is slow.")
.setCancelable(false)
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(
DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
}
});
private class CountDownTask extends AsyncTask<Void, Integer, Void> {
protected void onPreExecute() {
progressDialog = ProgressDialog.show(MainPage.this, "Loading...",
"Loading application , please wait...", false, false);
}
protected Void doInBackground(Void... params) {
call();
return null;
}
protected void onProgressUpdate(Integer... values) {
progressDialog.setProgress(values[0]);
}
protected void onPostExecute(Void result) {
progressDialog.dismiss();
}
}
01-31 10:41:37.575: E/AndroidRuntime(9038): FATAL EXCEPTION: AsyncTask #1
01-31 10:41:37.575: E/AndroidRuntime(9038): java.lang.RuntimeException: An error occured while executing doInBackground()
01-31 10:41:37.575: E/AndroidRuntime(9038): at android.os.AsyncTask$3.done(AsyncTask.java:278)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.lang.Thread.run(Thread.java:856)
01-31 10:41:37.575: E/AndroidRuntime(9038): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
01-31 10:41:37.575: E/AndroidRuntime(9038): at android.os.Handler.<init>(Handler.java:121)
01-31 10:41:37.575: E/AndroidRuntime(9038): at android.app.Activity.<init>(Activity.java:735)
01-31 10:41:37.575: E/AndroidRuntime(9038): at com.example.collegesoft.SyncData.<init>(SyncData.java:22)
01-31 10:41:37.575: E/AndroidRuntime(9038): at com.example.collegesoft.MainPage.call(MainPage.java:259)
01-31 10:41:37.575: E/AndroidRuntime(9038): at com.example.collegesoft.MainPage$CountDownTask.doInBackground(MainPage.java:284)
01-31 10:41:37.575: E/AndroidRuntime(9038): at com.example.collegesoft.MainPage$CountDownTask.doInBackground(MainPage.java:1)
01-31 10:41:37.575: E/AndroidRuntime(9038): at android.os.AsyncTask$2.call(AsyncTask.java:264)
01-31 10:41:37.575: E/AndroidRuntime(9038): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
01-31 10:41:37.575: E/AndroidRuntime(9038): ... 4 more
01-31 10:41:43.966: E/WindowManager(9038): Activity com.example.collegesoft.MainPage has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41753818 that was originally added here
01-31 10:41:43.966: E/WindowManager(9038): android.view.WindowLeaked: Activity com.example.collegesoft.MainPage has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41753818 that was originally added here
01-31 10:41:43.966: E/WindowManager(9038): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:383)
01-31 10:41:43.966: E/WindowManager(9038): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:279)
01-31 10:41:43.966: E/WindowManager(9038): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
01-31 10:41:43.966: E/WindowManager(9038): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
01-31 10:41:43.966: E/WindowManager(9038): at android.view.Window$LocalWindowManager.addView(Window.java:537)
01-31 10:41:43.966: E/WindowManager(9038): at android.app.Dialog.show(Dialog.java:278)
01-31 10:41:43.966: E/WindowManager(9038): at android.app.ProgressDialog.show(ProgressDialog.java:116)
01-31 10:41:43.966: E/WindowManager(9038): at android.app.ProgressDialog.show(ProgressDialog.java:104)
01-31 10:41:43.966: E/WindowManager(9038): at com.example.collegesoft.MainPage$CountDownTask.onPreExecute(MainPage.java:278)
01-31 10:41:43.966: E/WindowManager(9038): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:561)
01-31 10:41:43.966: E/WindowManager(9038): at android.os.AsyncTask.execute(AsyncTask.java:511)
01-31 10:41:43.966: E/WindowManager(9038): at com.example.collegesoft.MainPage$3$1$1.run(MainPage.java:82)
01-31 10:41:43.966: E/WindowManager(9038): at android.os.Handler.handleCallback(Handler.java:605)
01-31 10:41:43.966: E/WindowManager(9038): at android.os.Handler.dispatchMessage(Handler.java:92)
01-31 10:41:43.966: E/WindowManager(9038): at android.os.Looper.loop(Looper.java:137)
01-31 10:41:43.966: E/WindowManager(9038): at android.app.ActivityThread.main(ActivityThread.java:4514)
01-31 10:41:43.966: E/WindowManager(9038): at java.lang.reflect.Method.invokeNative(Native Method)
01-31 10:41:43.966: E/WindowManager(9038): at java.lang.reflect.Method.invoke(Method.java:511)
01-31 10:41:43.966: E/WindowManager(9038): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
01-31 10:41:43.966: E/WindowManager(9038): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
01-31 10:41:43.966: E/WindowManager(9038): at dalvik.system.NativeStart.main(Native Method)
我的call（）方法......
protected void call() {
Log.d(TAG,"Call Called");
myDbHelper = new DatabaseHelper(MainPage.this);
try {
myDbHelper.openDataBase();
} catch (SQLException sqle) {
throw sqle;
}
Cursor c = myDbHelper.getAllStudentFromMainTable();
Log.d(TAG, "Cursor : " + c.getColumnCount());
//new CountDownTask().execute();
new SyncData().sendJson(c, myDbHelper, MainPage.this);
//c.close();
}
答案 0 :(得分：1)
您可以在活动中创建处理程序，然后使用它来发布您需要执行的操作。
示例：
public void onAvatarChange(View v) {
final Handler uiHandler = new Handler();
//Build dialog....
OnclickListener onYes = new OnClickListener {
public void onClick(View v) {
uiHanlder.post(new Runnable() {
public void run() {
//Do whatever you want here...
//You will have looper.prepare here, as it will run on main thread as soon as possible.
}
}
}
}
}
答案 1 :(得分：0)
这怎么可能？
new CountDownTask().execute();
MainPage.this.finish();
Intent i = new Intent("com.example.collegesoft.MainPage");
startActivity(i);
我的意思是，在某一点上，您正在执行AsyncTask，同时您正在开始新的活动。所以它只是因为你在CountDownTask中显示了ProgressDialog而给你错误。
相反，建议的解决方案是在CountDownTask（）的onPostExecute（）方法中包含startActivity（）代码：
protected void onPostExecute(Void result) {
progressDialog.dismiss();
MainPage.this.finish();
Intent i = new Intent("com.example.collegesoft.MainPage");
startActivity(i);
}
答案 2 :(得分：0)
runOnUiThread(new Runnable() {
@Override
public void run() {
// start your asynch task here
}
});