Question

使用TextureView我的应用相机预览。

现在的情况，在我的应用中点击button启动wifiapp

Intent intent = getPackageManager().getLaunchIntentForPackage("kr.co.aaa.wifiapp");
startActivity(intent);

目前，请致电onSurfaceTextureDestroyed，onPause

@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
    mCamera.setPreviewCallback(null);
    mCamera.release();
    mCamera = null;
}

并在wifiapp中，点击后退button，重启我的应用。

此时，请致电onSurfaceTextureAvailable

@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int width, int height) {
  try {  
       mCamera.setPreviewTexture(surfaceTexture);  //NPE
       mCamera.startPreview();
  } catch (IOException e) {
      e.printStackTrace();
  }
}

重启我的应用时，会发生NullPointerException

java.lang.NullPointerException：尝试调用虚方法＆＃39; void android.hardware.Camera.setPreviewTexture（android.graphics.SurfaceTexture）＆＃39; 在null对象引用上 at kr.co.iosystem.blackeyeonandroid.video.CameraTextureView.onSurfaceTextureAvailable（CameraTextureView.java:82）在android.view.TextureView.getHardwareLayer（TextureView.java:368）在android.view.View.updateDisplayListIfDirty（View.java:15157）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在com.android.internal.policy.PhoneWindow $ DecorView.draw（PhoneWindow.java:2690）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.ThreadedRenderer.updateViewTreeDisplayList（ThreadedRenderer.java:282）在android.view.ThreadedRenderer.updateRootDisplayList（ThreadedRenderer.java:288）在android.view.ThreadedRenderer.draw（ThreadedRenderer.java:323）在android.view.ViewRootImpl.draw（ViewRootImpl.java:2609）在android.view.ViewRootImpl.performDraw（ViewRootImpl.java:2428）在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:2061）在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1107）在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:6007）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:858）在android.view.Choreographer.doCallbacks（Choreographer.java:670）在android.view.Choreographer.doFrame（Choreographer.java:606）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:844）在android.os.Handler.handleCallback（Handler.java:739）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:148）在android.app.ActivityThread.main（ActivityThread.java:5415） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:745）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:635）

我认为发生了NPE onSurfaceTextureDestroyed mCamera = null;。

因为当我的应用重启时，mCamera状态为空调用onSurfaceTextureAvailable，mCamera.setPreviewTexture(surfaceTexture)为空。

所以我尝试删除mCamera = null

但会出现不同的错误。

java.lang.RuntimeException：之后正在使用相机调用了Camera.release（）在android.hardware.Camera.setPreviewTexture（本机方法） at kr.co.iosystem.blackeyeonandroid.video.CameraTextureView.onSurfaceTextureAvailable（CameraTextureView.java:82）在android.view.TextureView.getHardwareLayer（TextureView.java:368）在android.view.View.updateDisplayListIfDirty（View.java:15157）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.updateDisplayListIfDirty（View.java:15175）在android.view.View.draw（View.java:15954）在android.view.ViewGroup.drawChild（ViewGroup.java:3609）在android.view.ViewGroup.dispatchDraw（ViewGroup.java:3399）在android.view.View.draw（View.java:16187）在com.android.internal.policy.PhoneWindow $ DecorView.draw（PhoneWindow.java:2690）在android.view.View.updateDisplayListIfDirty（View.java:15180）在android.view.ThreadedRenderer.updateViewTreeDisplayList（ThreadedRenderer.java:282）在android.view.ThreadedRenderer.updateRootDisplayList（ThreadedRenderer.java:288）在android.view.ThreadedRenderer.draw（ThreadedRenderer.java:323）在android.view.ViewRootImpl.draw（ViewRootImpl.java:2609）在android.view.ViewRootImpl.performDraw（ViewRootImpl.java:2428）在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:2061）在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1107）在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:6007）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:858）在android.view.Choreographer.doCallbacks（Choreographer.java:670）在android.view.Choreographer.doFrame（Choreographer.java:606）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:844）在android.os.Handler.handleCallback（Handler.java:739）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:148）在android.app.ActivityThread.main（ActivityThread.java:5415） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:745）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:635）

此错误mCamera.setPrevieTexture(surfaceTexture)

如何解决这个问题？

感谢。

完整的来源

public class CameraTexture extends TextureView implement TextureView.SurfaceTextureListener {
  private Camera mCamera;
  private TextureView mTextureView;

  public CameraTexture(Context context, LiveCamera liveCamera) {
    super(context);

    mCamera = liveCamera.camera;

    mTextureVeiw = (TextureView) activity.findViewById(R.id.live);
    mTextureView.setSurfaceTextureListener(this);
 }

 @Override 
 public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int width, int height) {

   try {
      mCamera.setPreviewTexture(surfaceTexture);
      mCamera.startPreview();
   } catch (IOException e) {
      e.printStackTrace();
   } 
 }

 @Override 
 public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i2) {
 }

 @Override
 public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
       mCamera.setPreviewCallback(null);
       mCamera.release();
       mCamera = null; // if delete this line, occur Camera is being used after Camera.release() was called  error
 }

 @Override
 public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
    Bitmap bitmap = mTextureView.getBitmap();

    int width = bitmap.getWidth();
    int height = bitmap.getHeight();

    int[] pixels = new int[bitmap.getHeight() * bitmap.getWidth()];
    bitmap.getPixels(pixels, 0, width, 0, 0, width, height);
 }
 }


public class LiveCamera {
   public Camera camera;
}

如果需要更多信息。请评论。感谢！

Answer 1

请检查您的班级名称和构造名称

public class CameraTexture extends TextureView implement TextureView.SurfaceTextureListener {
  private Camera mCamera;
  private TextureView mTextureView;

  public CameraTexture(Context context, LiveCamera liveCamera) {
    super(context);

    mCamera = liveCamera.camera;

    mTextureVeiw = (TextureView) activity.findViewById(R.id.live);
    mTextureView.setSurfaceTextureListener(this);
 }

//your remain code

}

Answer 2

将surfacetexture对象保存为全局变量，如果为null，则尝试从全局变量中获取保存的对象。

使用Camera TextureView时，在android

2 个答案: