java - BitmapDrawable 无法转换为 AnimationDrawable

Question

我正在开发一个应用程序，一旦我摇动手机，它就会执行某项功能。为此，我创建了一个名为 ShakeListener 的类。当我打开它时，我的应用程序运行得非常好。当我打开应用程序并按后退按钮并转到主屏幕并摇动手机时，它会打开闪光灯(就像预期的那样)，但当我再次打开应用程序时，它崩溃了。我不知道为什么会这样

我的主要 Activity 是

public class MainActivity extends ActionBarActivity   {
 @Override
protected void onResume() {
    // TODO Auto-generated method stub
        super.onResume();
        SharedPreferences getprefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
        boolean stopshake = getprefs.getBoolean("checkbox", true);
        if (stopshake) {
            mShaker = new ShakeListener(this); 
            mShaker.setOnShakeListener(new ShakeListener.OnShakeListener () {
                public void onShake() { 
                    if (!isFlashOn && mShaker != null ) {

                        getCamera();
                        turnOnFlash();
                    } else {
                        turnOffFlash();

                    }
                }
            });
        } else {
            if (mShaker != null) {
                mShaker.setOnShakeListener(null);
                mShaker = null;
            }
        }    
}

private ToggleButton togle;
 private Camera camera;
    private boolean isFlashOn;

    private boolean hasFlash;
    Parameters params;
    private ShakeListener mShaker;
    MediaPlayer mp;
    ImageView anime;
    int p=1; 
@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    anime = (ImageView) findViewById(R.id.Animation);

    hasFlash = getApplicationContext().getPackageManager()
            .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

    if (!hasFlash) {
        // device doesn't support flash
        // Show alert message and close the application
        AlertDialog alert = new AlertDialog.Builder(MainActivity.this)
                .create();
        alert.setTitle("Error");
        alert.setMessage("Sorry, your device doesn't support flash light!");
        alert.setButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                // closing the application
                finish();   }
        });
        alert.show();
        return;}


    getCamera();


    togle = (ToggleButton) findViewById(R.id.ToggleButton01);

    togle.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
        // TODO Auto-generated method stub
              boolean checked = ((ToggleButton) v).isChecked();
               if (checked){
                   turnOffFlash();
              }

               else{
                   getCamera();
                   turnOnFlash(); 
               }
                  }
        });


    }

private void getCamera() {
    // TODO Auto-generated method stub
    if (camera == null) {
        try {
            camera = Camera.open();
            params = camera.getParameters();
        } catch (RuntimeException e) {
            Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());
        }
    } }

private void turnOnFlash() {
    if (!isFlashOn) {
        if (camera == null || params == null) {
            return;
        }
        // play sound
        getCamera();
        playSound();

        params = camera.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_TORCH);
        camera.setParameters(params);
        camera.startPreview();
        isFlashOn = true;
        anime.setImageResource(R.drawable.anim);
        anime.post(new Runnable() {
            @Override
            public void run() {
                AnimationDrawable frameAnimation =
                    (AnimationDrawable) anime.getDrawable(); 
                frameAnimation.start();
            }
        });

        // changing button/switch image
    }
  }

 private void turnOffFlash() {
        if (isFlashOn) {
            if (camera == null || params == null) {
                return;
            }
            // play sound
            playSound();

            params = camera.getParameters();
            params.setFlashMode(Parameters.FLASH_MODE_OFF);
            camera.setParameters(params);
            camera.stopPreview();
            camera.setPreviewCallback(null);
            camera.release();
            camera = null;
            isFlashOn = false;
            anime.setImageResource(R.drawable.off);
            // changing button/switch image
        }
    }

private void playSound() {
    // TODO Auto-generated method stub
     if(isFlashOn){
            mp = MediaPlayer.create(MainActivity.this, R.raw.off1);
        }else{
            mp = MediaPlayer.create(MainActivity.this, R.raw.on1);
        }
        mp.setOnCompletionListener(new OnCompletionListener() {

            @Override
            public void onCompletion(MediaPlayer mp) {
                // TODO Auto-generated method stub
                mp.release();
            }
        }); 
        mp.start();
}

@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.
    super.onOptionsItemSelected(item);
     switch(item.getItemId()){
     case R.id.action_settings:
         Intent intent = new Intent(MainActivity.this, Prefsetting.class);
        startActivity(intent);
         break;

     case R.id.about:
         AlertDialog.Builder dlgAlert  = new AlertDialog.Builder(this);
         dlgAlert.setMessage("This is an alert with no consequence");
         dlgAlert.setTitle("App Title");
         dlgAlert.setPositiveButton("OK", null);
         dlgAlert.setCancelable(true);
         dlgAlert.create().show();
         break;

 }
 return true;


}   
       }

我的 logcat 显示

08-23 04:31:53.205: D/ShakeListener(11990): ShakeListener invoked----> 08-23 04:31:53.207: D/ShakeListener(11990): ShakeListener setOnShakeListener invoked----> 08-23 04:31:53.312: D/AndroidRuntime(11990): Shutting down VM 08-23 04:31:53.314: E/AndroidRuntime(11990): FATAL EXCEPTION: main 08-23 04:31:53.314: E/AndroidRuntime(11990): Process: com.shakylight, PID: 11990 08-23 04:31:53.314: E/AndroidRuntime(11990): java.lang.ClassCastException: android.graphics.drawable.BitmapDrawable cannot be cast to android.graphics.drawable.AnimationDrawable 08-23 04:31:53.314: E/AndroidRuntime(11990): at com.shakylight.MainActivity$4.run(MainActivity.java:145) 08-23 04:31:53.314: E/AndroidRuntime(11990): at android.os.Handler.handleCallback(Handler.java:739) 08-23 04:31:53.314: E/AndroidRuntime(11990): at android.os.Handler.dispatchMessage(Handler.java:95) 08-23 04:31:53.314: E/AndroidRuntime(11990): at android.os.Looper.loop(Looper.java:135) 08-23 04:31:53.314: E/AndroidRuntime(11990): at android.app.ActivityThread.main(ActivityThread.java:5254) 08-23 04:31:53.314: E/AndroidRuntime(11990): at java.lang.reflect.Method.invoke(Native Method) 08-23 04:31:53.314: E/AndroidRuntime(11990): at java.lang.reflect.Method.invoke(Method.java:372) 08-23 04:31:53.314: E/AndroidRuntime(11990): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 08-23 04:31:53.314: E/AndroidRuntime(11990): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

当您转换时，问题似乎出现在以下行:

AnimationDrawable frameAnimation = (AnimationDrawable) anime.getDrawable(); 

您正在 ImageView 上使用 anime.setImageResource() 来设置您的可绘制对象。请尝试使用 anime.setImageDrawable(getResource().getDrawable(R.drawable.anim); 并查看错误是否仍然存在。