我有一个应用程序来获取带有表面的相机预览帧。它可以在Android 4.0.4上运行,但在更新后在同一设备上与Jelly Bean,4.1.2不起作用。 简单地说,回调永远不会被回调。这是代码: 剪了一点:
public class Panel extends Activity {
Camera myCamera;
int cameraId = -1;
MyCameraSurfaceView myCameraSurfaceView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_panel);
myCamera = getCameraInstance();
myCamera.setPreviewCallback(new Camera.PreviewCallback() {
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Log.d("Camera Preview", data.length + "");
}
});
myCameraSurfaceView = new MyCameraSurfaceView(this, myCamera);
FrameLayout myCameraPreview = (FrameLayout) findViewById(R.id.videoview);
myCameraPreview.addView(myCameraSurfaceView);
}
private Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open();
} catch (Exception e) {
e.printStackTrace();
}
return c;
}
public class MyCameraSurfaceView extends SurfaceView implements
SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public MyCameraSurfaceView(Context context, Camera camera) {
super(context);
mCamera = camera;
mHolder = getHolder();
mHolder.addCallback(this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
}
}
}
}
视频帧显示在活动中,因此我无法弄清楚我做错了什么。
我使用另一个教程重写了代码。它可以工作,但现在更慢了。我不知道确切的原因(可能是由于我使用的N7000 ROM泄漏,它可能有一个错误,或者在4.1中以不同的方式实现,不确定)
相机预览.java
public class CameraPreview implements SurfaceHolder.Callback,
Camera.PreviewCallback {
int PreviewSizeWidth;
int PreviewSizeHeight;
SurfaceHolder mSurfHolder;
Camera mCamera;
public CameraPreview(int PreviewlayoutWidth, int PreviewlayoutHeight) {
PreviewSizeWidth = PreviewlayoutWidth;
PreviewSizeHeight = PreviewlayoutHeight;
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Parameters p = camera.getParameters();
int width = p.getPreviewSize().width;
int height = p.getPreviewSize().height;
ByteArrayOutputStream outstr = new ByteArrayOutputStream();
Rect rect = new Rect(0, 0, width, height);
YuvImage yuvimage = new YuvImage(data, ImageFormat.NV21, width,
height, null);
yuvimage.compressToJpeg(rect, 80, outstr); // outstr contains image in jpeg
String encodedImage = Base64.encodeToString(
outstr.toByteArray(), Base64.DEFAULT); // this is base64 encoding of image
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
Parameters parameters;
mSurfHolder = arg0;
parameters = mCamera.getParameters();
parameters.setPreviewSize(PreviewSizeWidth, PreviewSizeHeight);
mCamera.setParameters(parameters);
mCamera.startPreview();
}
public void surfaceCreated(SurfaceHolder arg0) {
mCamera = Camera.open();
try {
// If did not set the SurfaceHolder, the preview area will be black.
mCamera.setPreviewDisplay(arg0);
mCamera.setPreviewCallback(this);
Parameters p = mCamera.getParameters();
p.setPreviewSize(PreviewSizeWidth, PreviewSizeHeight);
mCamera.setParameters(p);
} catch (IOException e) {
mCamera.release();
mCamera = null;
}
}
@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
小组活动.java
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_panel);
SurfaceView camView = new SurfaceView(this);
SurfaceHolder camHolder = camView.getHolder();
int width = 352; // must set a compatible value, otherwise it gets the default width and height
int height = 288;
camPreview = new CameraPreview(width, height);
camHolder.addCallback(camPreview);
camHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
mainLayout = (FrameLayout) findViewById(R.id.videoview);
mainLayout.addView(camView, new LayoutParams(width, height));
}