android - Temboo execute() 无法在未调用 Looper.prepare() 的线程内创建处理程序

Question

我正在运行 Temboo Google 距离矩阵。 https://temboo.com/library/Library/Google/DistanceMatrix/DrivingDistanceMatrix/

所以我在单独的 AsyncTask 中运行 InputSet，然后在该 AsyncTask 的 onPostExecute 方法中，我启动另一个 AsyncTask 来运行 ResultSet。

我没有将它们放在 1 个后台任务中的原因是因为 ResultSet 的 .execute() 方法打开了另一个线程(我认为)，所以我会在那里出现并发异常。

我也不能只在 onPostExecute() 方法中调用 .execute()，因为您不能在主线程中进行网络调用。

但是，即使我的程序现在在单独的线程上运行，我的程序仍然会在这一行崩溃:

DrivingDistanceMatrixResultSet drivingDistanceMatrixResults = drivingDistanceMatrixChoreo.execute(drivingDistanceMatrixInputSet);

这是我的代码

public class BackgroundTembooInputs extends AsyncTask<String[], Void, Void> {
    private static DrivingDistanceMatrix drivingDistanceMatrixChoreo;
    private static DrivingDistanceMatrixInputSet drivingDistanceMatrixInputs;

    public BackgroundTembooInputs() {
    }

    @Override
    protected Void doInBackground(String[]... params) {
        TembooSession session = null;
        try {
            session = new TembooSession("accName", "appName", "appKey");

            drivingDistanceMatrixChoreo = new DrivingDistanceMatrix(session);

            drivingDistanceMatrixInputs = drivingDistanceMatrixChoreo.newInputSet();

            drivingDistanceMatrixInputs.set_Destinations("some addr"); 
            drivingDistanceMatrixInputs.set_Origins("some addr");

        } catch (TembooException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        BackgroundTembooOutputs backgroundTembooOutputs = new BackgroundTembooOutputs(mainWindowActivity);
        backgroundTembooOutputs.execute();
    }

    public static DrivingDistanceMatrix getDrivingDistanceMatrixChoreo() {
        return drivingDistanceMatrixChoreo;
    }

    public static DrivingDistanceMatrixInputSet getDrivingDistanceMatrixInputs() {
        return drivingDistanceMatrixInputs;
    }
}

public class BackgroundTembooOutputs extends AsyncTask<Void, Void, Void> {
    public BackgroundTembooOutputs(MainWindowActivity mainWindowActivity) {

    }

    @Override
    protected Void doInBackground(Void... params) {
        DrivingDistanceMatrix drivingDistanceMatrixChoreo = BackgroundTembooInputs.getDrivingDistanceMatrixChoreo();
        DrivingDistanceMatrixInputSet drivingDistanceMatrixInputSet = BackgroundTembooInputs.getDrivingDistanceMatrixInputs();

        try {
            // ERROR HERE
            DrivingDistanceMatrixResultSet drivingDistanceMatrixResults = drivingDistanceMatrixChoreo.execute(drivingDistanceMatrixInputSet);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}

还有 Logcat:

08-20 01:35:32.163  19533-19550/edu.drexel.cs.ptn32.hw2 E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    Process: prog, PID: 19533
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:304)
            at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
            at java.util.concurrent.FutureTask.run(FutureTask.java:242)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)
     Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
            at android.os.Handler.<init>(Handler.java:200)
            at android.os.Handler.<init>(Handler.java:114)
            at android.widget.Toast$TN.<init>(Toast.java:344)
            at android.widget.Toast.<init>(Toast.java:100)
            at android.widget.Toast.makeText(Toast.java:258)
            at prog.BackgroundTembooOutputs.doInBackground(BackgroundTembooOutputs.java:35)
            at prog.BackgroundTembooOutputs.doInBackground(BackgroundTembooOutputs.java:17)
            at android.os.AsyncTask$2.call(AsyncTask.java:292)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)

Answer 1

您不能在 AsyncTask.doInBackground 中创建 Toast(因为它不在 UI 线程上运行)- 将 Toast 创建移动到 AsyncTask.onPreExecute 或 AsyncTask.onPostExecute