应用程式在android studio（2.2.3）的Android模拟器中当机

Question

我正在尝试制作一个显示加速度计的x，y，z值的应用程序。
我的activity_main.xml中有此代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="92dp"
        android:layout_marginTop="114dp"
        android:text="TextView" />

</RelativeLayout>

以下是MainActivity.java代码：

package com.example.sensorsimple;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
import android.hardware.SensorManager;
import android.hardware.SensorEventListener;
import android.hardware.SensorEvent;
import android.hardware.Sensor;
import java.util.List;
public class MainActivity extends Activity {
    SensorManager sm = null;
    TextView accText = null;
    List list;

    /* This responds to sensor events */
    SensorEventListener sel = new SensorEventListener(){
        public void onAccuracyChanged(Sensor sensor, int accuracy) {
            /* Isn't required for this example */

        }
        public void onSensorChanged(SensorEvent event) {
            /* Write the accelerometer values to the TextView */
            float[] values = event.values;
            accText.setText("x: "+values[0]+"\ny: "+values[1]+"\nz: "+values[2]);
        }

    };

    /* Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        /* Get a SensorManager instance */
        sm = (SensorManager)getSystemService(SENSOR_SERVICE);

        /* This corresponds to a TextView element in main.xml with android:id="@+id/accText" */
        accText = (TextView)findViewById(R.id.textView1);

        /* Get list of accelerometers */
        list = sm.getSensorList(Sensor.TYPE_ACCELEROMETER);

        /* If there are any accelerometers register a listener to the first else
           print a little error message */
        if(list.size()>0){
            sm.registerListener(sel, (Sensor) list.get(0), SensorManager.SENSOR_DELAY_NORMAL);
        }else{
            Toast.makeText(getBaseContext(), "Error: No Accelerometer.", Toast.LENGTH_LONG);
        }
    }

    @Override
    protected void onStop() {
        /* Always a good idea to unregister, disconnect, close, etc things */
        if(list.size()>0){
            /* This actually unregisters a listener for all sensors, but it can be done
               on a sensor by sensor basis */
            sm.unregisterListener(sel);
        }
        super.onStop();
    }

当我在android studio（API 24，Android N）中运行此AVD时，该应用程序崩溃，并在模拟器屏幕上停止了[APP name]错误。如何运行此程序？ 这就是我得到的错误

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.sid.javatpoint_sensor_values, PID: 15266
                  java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.sid.javatpoint_sensor_values/com.example.sid.javatpoint_sensor_values.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.sid.javatpoint_sensor_values.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.sid.javatpoint_sensor_values-2/base.apk"],nativeLibraryDirectories=[/data/app/com.example.sid.javatpoint_sensor_values-2/lib/x86, /system/lib, /vendor/lib]]
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2548)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
                      at android.app.ActivityThread.-wrap12(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6077)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                   Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.sid.javatpoint_sensor_values.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.sid.javatpoint_sensor_values-2/base.apk"],nativeLibraryDirectories=[/data/app/com.example.sid.javatpoint_sensor_values-2/lib/x86, /system/lib, /vendor/lib]]
                      at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                      at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
                      at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
                      at android.app.Instrumentation.newActivity(Instrumentation.java:1078)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2538)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
                      at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6077) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 

Answer 1

您应该检查您的AndroidManifest.xml文件，因为它会尝试查找com.example.sid.javatpoint_sensor_values.MainActivity，并且您的MainActivity放置在com.example.sensorsimple包中。 如果您的AndroidManifest.xml正常，请尝试清理您的项目