问题描述

Android Camera2的使用到底是哪里错了？

代码如下：

public class CameraTwoActivity extends AppCompatActivity implements TextureView.SurfaceTextureListener {

@Bind(R.id.textureview)android.view.TextureView mPreviewView;private Handler mHandler;private HandlerThread mThreadHandler;private Size mPreviewSize=null;private CaptureRequest.Builder mPreviewBuilder;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.camera_activity);    ButterKnife.bind(this);    mThreadHandler = new HandlerThread(""CAMERA2"");    mThreadHandler.start();    mHandler = new Handler(mThreadHandler.getLooper());    mPreviewView.setSurfaceTextureListener(this);}@TargetApi(Build.VERSION_CODES.LOLLIPOP)public void onSurfaceTextureAvailable(SurfaceTexture surface int width int height) {    try {        //获得CameraManager        CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);        //获得属性        CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(""0"");        //支持的STREAM CONFIGURATION        StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);        //显示的size        mPreviewSize = map.getOutputSizes(SurfaceTexture.class)[0];        //打开相机        if (ActivityCompat.checkSelfPermission(this Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {            // TODO: Consider calling            //    ActivityCompat#requestPermissions            // here to request the missing permissions and then overriding            //   public void onRequestPermissionsResult(int requestCode String[] permissions            //                                          int[] grantResults)            // to handle the case where the user grants the permission. See the documentation            // for ActivityCompat#requestPermissions for more details.            return;        }        cameraManager.openCamera(""0"" mCameraDeviceStateCallback mHandler);    } catch (Exception e) {        e.printStackTrace();    }}@Overridepublic void onSurfaceTextureSizeChanged(SurfaceTexture surface int width int height) {}@Overridepublic boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {    return false;}//TextureView.SurfaceTextureListener@Overridepublic void onSurfaceTextureUpdated(SurfaceTexture surface) {}private CameraDevice.StateCallback mCameraDeviceStateCallback = new CameraDevice.StateCallback() {    @Override    public void onOpened(CameraDevice camera) {        try {            startPreview(camera);        } catch (CameraAccessException e) {            e.printStackTrace();        }    }    @Override    public void onDisconnected(CameraDevice camera) {    }    @Override    public void onError(CameraDevice camera int error) {    }};//开始预览，主要是camera.createCaptureSession这段代码很重要，创建会话private void startPreview(CameraDevice camera) throws CameraAccessException {    SurfaceTexture texture = mPreviewView.getSurfaceTexture();    texture.setDefaultBufferSize(mPreviewSize.getWidth() mPreviewSize.getHeight());    Surface surface = new Surface(texture);    Log.i(getClass().getName()1111"");    try {        mPreviewBuilder = camera.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);    } catch (CameraAccessException e) {        Log.i(getClass().getName()2222"");        e.printStackTrace();    }    Log.i(getClass().getName()3333"");    mPreviewBuilder.addTarget(surface);    camera.createCaptureSession(Arrays.asList(surface) mSessionStateCallback mHandler);}private CameraCaptureSession.StateCallback mSessionStateCallback = new CameraCaptureSession.StateCallback() {    @Override    public void onConfigured(CameraCaptureSession session) {        try {            updatePreview(session);        } catch (CameraAccessException e) {            e.printStackTrace();        }    }    @Override    public void onConfigureFailed(CameraCaptureSession session) {    }};private void updatePreview(CameraCaptureSession session) throws CameraAccessException {    session.setRepeatingRequest(mPreviewBuilder.build() null mHandler);}

}

解决方案

As the log said you are trying to get width from a Null object.
texture.setDefaultBufferSize(mPreviewSize.getWidth() mPreviewSize.getHeight());
mPreviewSize = null

解决方案二：
空指针错误 你可以在打印的logcat信息的下面 有一个 你的类的代码行 提示 会 定位到 哪一行的

解决方案三：
楼主，问题解决了没？这个camera2我也不会用。
你的代码里有一句。mThreadHandler = new HandlerThread(""CAMERA2"");
我看到SDK->Samples->media->Camera2Basic里用的是 new HandlerThread(""CameraBackground"")