让我的SurfaceView
显示我的相机预览有点麻烦。我在这里看了一些问题,谷歌了一些tuts,但我认为这可能是我这边的一个小错误,我只是没有看到。
public class RoofPitchActivity extends Activity implements SensorEventListener {
...
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
private Camera mCamera;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_roof_pitch);
initViews();
}
private void initViews() {
...
Preview preview = new Preview(this);
mCamera = Camera.open();
preview.setCamera(mCamera);
}
...
...
class Preview extends ViewGroup implements SurfaceHolder.Callback {
public Preview(Context context) {
super(context);
mSurfaceView = (SurfaceView) findViewById(R.id.preview);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
}
public void setCamera(Camera camera) {
if (mCamera == camera) {
return;
}
stopPreviewAndFreeCamera();
mCamera = camera;
if (mCamera != null) {
requestLayout();
try {
mCamera.setPreviewDisplay(mSurfaceHolder);
} catch (IOException e) {
e.printStackTrace();
}
mCamera.startPreview();
}
}
private void stopPreviewAndFreeCamera() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mCamera.startPreview();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mSurfaceView.getWidth(), mSurfaceView.getHeight());
requestLayout();
mCamera.setParameters(parameters);
mCamera.startPreview();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (mCamera != null) {
mCamera.stopPreview();
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
}
}
}
所以当活动启动时,SurfaceView
是黑色的。相机似乎没有渲染预览到SurfaceView
上。我确信我遗漏了一些小的东西,或者可能只是对它的工作原理有一个根本性的误解。如果有一双新鲜的眼睛,稍加解释,我将不胜感激。由于
所以我的问题的答案最终是设备特定的。代码是可以接受的,但我用来调试的设备是Nexus 7。这意味着摄像头是正面的,对摄像头的正常调用不起作用。在这篇文章
中可以找到一个有趣和有趣的阅读Camera.open();
不起作用。必须使用
Camera.open(0);
所以我的代码结束了相机的条件检查,现在它工作得很好。
一样public void setCamera() {
stopPreviewAndFreeCamera();
PackageManager pm = getPackageManager();
boolean backCamera = pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
boolean frontCamera = pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT);
if (frontCamera) {
mCamera = Camera.open(0);
} else if (backCamera) {
mCamera = Camera.open();
}
if (mCamera != null) {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mSurfaceView.getWidth(), mSurfaceView.getHeight());
requestLayout();
try {
mCamera.setParameters(parameters);
mCamera.setPreviewDisplay(mSurfaceHolder);
} catch (IOException e) {
e.printStackTrace();
}
mCamera.startPreview();
}
}