我有一个listview有复选框。对于每个复选框(它们大约是3),它都有一个特定的AsyncTask。AsyncTask中的Android AlertDialog
我从来不知道选择什么复选框的用户,所以我不能把在异步任务AlertDialog的结束,因为我从来不知道,如果用户只选择了一个复选框,或两个或三个。
因为AsyncTask是按步骤执行的(只有当第一个Async完成的时候是第二个开始的时候),所以我想通过AlertDialog把所有的新AsyncTask都放到最后。
private class showMessageAsync extends AsyncTask<Void, Integer, String> {
@Override
protected String doInBackground(Void... params){
AlertDialog alertDialog;
alertDialog = new AlertDialog.Builder(getApplicationContext).create();
alertDialog.setTitle("The Process");
alertDialog.setIcon(R.drawable.success);
alertDialog.setCanceledOnTouchOutside(false);
alertDialog.setMessage("All done!");
alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent A = new Intent(DownloadActivity.this, Menu_activity.class);
startActivity(A);
finish();
}
});
alertDialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
Intent A = new Intent(DownloadActivity.this, Menu_activity.class);
startActivity(A);
finish();
}
});
alertDialog.show();
return "Executed";
}
}
这是错误:
10-21 04:24:34.117: E/AndroidRuntime(1026): FATAL EXCEPTION: AsyncTask
#4 10-21 04:24:34.117: E/AndroidRuntime(1026): java.lang.RuntimeException: An error occured while executing
doInBackground() 10-21 04:24:34.117: E/AndroidRuntime(1026): at
android.os.AsyncTask$3.done(AsyncTask.java:299) 10-21 04:24:34.117:
E/AndroidRuntime(1026): at
java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
10-21 04:24:34.117: E/AndroidRuntime(1026): at
java.util.concurrent.FutureTask.setException(FutureTask.java:219)
10-21 04:24:34.117: E/AndroidRuntime(1026): at
java.util.concurrent.FutureTask.run(FutureTask.java:239) 10-21
04:24:34.117: E/AndroidRuntime(1026): at
android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 10-21
04:24:34.117: E/AndroidRuntime(1026): at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
10-21 04:24:34.117: E/AndroidRuntime(1026): at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
10-21 04:24:34.117: E/AndroidRuntime(1026): at
java.lang.Thread.run(Thread.java:841) 10-21 04:24:34.117:
E/AndroidRuntime(1026): Caused by: java.lang.RuntimeException: Can't
create handler inside thread that has not called Looper.prepare()
10-21 04:24:34.117: E/AndroidRuntime(1026): at
android.os.Handler.<init>(Handler.java:197) 10-21 04:24:34.117:
E/AndroidRuntime(1026): at
android.os.Handler.<init>(Handler.java:111) 10-21 04:24:34.117:
E/AndroidRuntime(1026): at android.app.Dialog.<init>(Dialog.java:107)
10-21 04:24:34.117: E/AndroidRuntime(1026): at
android.app.AlertDialog.<init>(AlertDialog.java:114) 10-21
04:24:34.117: E/AndroidRuntime(1026): at
android.app.AlertDialog$Builder.create(AlertDialog.java:931) 10-21
04:24:34.117: E/AndroidRuntime(1026): at com.example.MyExample.DownloadActivity$showMessageAsync.doInBackground(DownloadActivity.java:487)
10-21 04:24:34.117: E/AndroidRuntime(1026): at com.example.MyExample.DownloadActivity$showMessageAsync.doInBackground(DownloadActivity.java:1)
10-21 04:24:34.117: E/AndroidRuntime(1026): at android.os.AsyncTask$2.call(AsyncTask.java:287) 10-21 04:24:34.117:
E/AndroidRuntime(1026): at java.util.concurrent.FutureTask.run(FutureTask.java:234) 10-21
04:24:34.117: E/AndroidRuntime(1026): ... 4 more
我打电话给我的AsyncTask这样:
if(list.get(0).isSelected() == true){
// list = class that contains checkboxs state
String[] params = {order, String.valueOf(limit_customers) };
customers.execute(params);
}
if(list.get(1).isSelected() == true){
String[] params = {order, String.valueOf(limit_products) };
products.execute(params);
}
// etc, and in the end of this:
showMessageAsync sM = new showMessageAsync();
sM.execute();
的错误是在这条线:
alertDialog = new AlertDialog.Builder(getApplicationContext()).create();
像魅力一样工作。谢谢。 – user2742861