Question

我正在尝试制作一个相当简单的测试应用程序，在唯一的活动屏幕上打印加速度计的值。但是当我运行它时，它会在main中出现致命错误：NetworkOnMainThreadException。

我试图跟踪它可能的原因并遵循this question来解决将所有模拟器调用放在各自的AsyncTask类中的问题。但是，我仍然得到错误。

我的MainActivity.java：

导入声明：

package com.example.chillii;

import org.openintents.sensorsimulator.hardware.Sensor;
import org.openintents.sensorsimulator.hardware.SensorEvent;
import org.openintents.sensorsimulator.hardware.SensorEventListener;
import org.openintents.sensorsimulator.hardware.SensorManagerSimulator;

import android.hardware.SensorManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

应该删除上述错误的3个AsyncTask类：

class ConnectToSimulator extends AsyncTask<SensorManagerSimulator, Void, Void>
{

    @Override
    protected Void doInBackground(SensorManagerSimulator ... arg0) {
        try{
            arg0[0].connectSimulator();
        }
        catch(Exception E)
        {
            Log.i("ConnectTaskError: ", E.getMessage());
        }
        return null;
    }
}

class RegisterToSimulator extends AsyncTask<Object, Void, Void> {      
    @Override
    protected Void doInBackground(Object... sm) {
        try{
            ((SensorManagerSimulator) sm[0]).registerListener((SensorEventListener) sm[1], ((SensorManagerSimulator) sm[0]).getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_FASTEST);
        }catch(Exception e)
        {
            Log.i("error", e.getMessage());
        }
        return null;
    }
}

class UnregisterFromSimulator extends AsyncTask<Object, Void, Void> {      
    @Override
    protected Void doInBackground(Object... sm) {
        try{
            ((SensorManagerSimulator) sm[0]).unregisterListener((SensorEventListener) sm[1]);
        }catch(Exception e)
        {
            Log.i("error : ", e.getMessage());
        }
        return null;
    }
}

我的MainActivity类。在onCreate（）中调用了三个AsyncTask类。 onResume（）和onPause（）（遵循SensorSimulator＆＃39; s wiki page上的文档）。另外，实现onSensorChanged（），它在相应的TextViews中输出三个值：

public class MainActivity extends ActionBarActivity implements SensorEventListener {

    private SensorManagerSimulator mSensorManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }

        mSensorManager = SensorManagerSimulator.getSystemService(this, SENSOR_SERVICE);
        new ConnectToSimulator().execute(mSensorManager);
        //mSensorManager.connectSimulator();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);
            return rootView;
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        new RegisterToSimulator().execute(mSensorManager, this);
    }

    @Override
    protected void onPause() {
        new UnregisterFromSimulator().execute(mSensorManager, this);
        super.onPause();
    }

    @Override
    public void onAccuracyChanged(Sensor arg0, int arg1) {
        // Auto-generated method stub

    }

    @Override
    public void onSensorChanged(SensorEvent E) {
        TextView tv;
        tv = (TextView) findViewById(R.id.xbox);
        tv.setText(Double.toString(E.values[0]));

        tv = (TextView) findViewById(R.id.ybox);
        tv.setText(Double.toString(E.values[1]));

        tv = (TextView) findViewById(R.id.zbox);
        tv.setText(Double.toString(E.values[2]));
    }
}

这是fragment_main.xml。主要是样板+ 3个TextView，默认情况下打印X，Y和Z：

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView android:id="@+id/xbox"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="X" />

        <TextView android:id="@+id/ybox"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Y" />

        <TextView android:id="@+id/zbox"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Z" />
    </LinearLayout>

</LinearLayout>

编辑：

logcat中的堆栈跟踪如下：

05-29 05:30:23.239: E/AndroidRuntime(2231): FATAL EXCEPTION: main
05-29 05:30:23.239: E/AndroidRuntime(2231): android.os.NetworkOnMainThreadException
05-29 05:30:23.239: E/AndroidRuntime(2231):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1133)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at libcore.io.BlockGuardOs.recvfrom(BlockGuardOs.java:163)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at libcore.io.IoBridge.recvfrom(IoBridge.java:506)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.net.PlainSocketImpl.read(PlainSocketImpl.java:488)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.net.PlainSocketImpl.access$000(PlainSocketImpl.java:46)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.net.PlainSocketImpl$PlainSocketInputStream.read(PlainSocketImpl.java:240)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.io.InputStreamReader.read(InputStreamReader.java:244)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.io.BufferedReader.fillBuf(BufferedReader.java:130)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.io.BufferedReader.readLine(BufferedReader.java:354)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at org.openintents.sensorsimulator.hardware.SensorSimulatorClient.readSensor(SensorSimulatorClient.java:654)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at org.openintents.sensorsimulator.hardware.SensorSimulatorClient.readSensor(SensorSimulatorClient.java:571)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at org.openintents.sensorsimulator.hardware.SensorSimulatorClient.access$1000(SensorSimulatorClient.java:53)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at org.openintents.sensorsimulator.hardware.SensorSimulatorClient$1.handleMessage(SensorSimulatorClient.java:505)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at android.os.Looper.loop(Looper.java:137)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at android.app.ActivityThread.main(ActivityThread.java:5103)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.lang.reflect.Method.invokeNative(Native Method)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at java.lang.reflect.Method.invoke(Method.java:525)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-29 05:30:23.239: E/AndroidRuntime(2231):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

因为您使用片段类并在主要活动类中调用异步任务删除以下行

 mSensorManager = SensorManagerSimulator.getSystemService(this, SENSOR_SERVICE);
 new ConnectToSimulator().execute(mSensorManager);

来自onCreate的

并将它放在PlaceholderFragment类中的onActivityCreated（）方法中... ...

尝试使用Sensor Simulator：给出NetworkOnMainThreadException

编辑：

1 个答案: