我正在使用带有SurfaceView的{{1}}来开始我的测试应用中的相机预览。
SurfaceHolder我想使用CameraPreview（随SDK版本7的SDK Samples一起提供）。点击UI即可拍照。这是public class TextLocatorActivity extends Activity {
private Preview pvw;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
pvw = new Preview(this);
setContentView(pvw);
}
类：
Preview}
接下来，我正在尝试对public class Preview extends SurfaceView implements OnClickListener, SurfaceHolder.Callback {
SurfaceHolder holder;
Camera cam;
final static String TAG = "TextLocator:Preview";
Preview(Context context) {
super(context);
holder = getHolder();
holder.addCallback(this);
this.setOnClickListener(this);
// seems to be required (although the docs state, this enum is deprecated, as the type will be chosen automatically...
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
cam = Camera.open();
try {
Camera.Parameters params = cam.getParameters();
params.set("orientation", "landscape");
Camera.Size bestSize = getBestPreviewSize(480, 320);
params.setPreviewSize(bestSize.width, bestSize.height);
cam.setParameters(params);
// where to draw:
cam.setPreviewDisplay(holder);
} catch (IOException exception) {
cam.release();
cam = null;
// TODO: add more exception handling logic here
}
}
private Camera.Size getBestPreviewSize(int width, int height)
{
// checks for supported sizes close to the demanded values - implemented.
}
public void surfaceDestroyed(SurfaceHolder holder) {
cam.stopPreview();
cam.release();
cam = null;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Camera.Parameters parameters = cam.getParameters();
parameters.setPreviewSize(w, h);
cam.setParameters(parameters);
cam.startPreview();
}
Camera.PictureCallback picCallback = new Camera.PictureCallback() {
public void onPictureTaken(byte[] bytes, Camera arg1) {
synchronized(holder) {
Canvas c = null;
try {
c = holder.lockCanvas();
Paint paint = new Paint();
paint.setAntiAlias(false);
paint.setARGB(200, 120, 180, 0);
c.drawLine(10, 10, c.getWidth() - 10, c.getHeight() - 10, paint);
}
catch (Exception e) {
Log.d(TAG, "Exception: " + e.getMessage());
// IllegalArguementException Surface Type is SURFACE_TYPE_PUSH_BUFFERS
}
finally {
holder.unlockCanvasAndPost(c);
}
}
}
};
public void onClick(View v)
{
cam.takePicture(null, null, picCallback);
}
的相应Canvas进行一些额外的绘画。所以我打电话给SurfaceHolder。这将导致canvas = holder.lockCanvas()带有消息：
IllegalArgumentException现在，docs声明不推荐使用这些表面类型，将忽略值集。但是，如果我将类型设置为此特定值，则相机预览仅起作用。
如何在Surface type is SURFACE_TYPE_PUSH_BUFFERS
Canvas上显示所拍照片？或者应该将其放在不同的图层/视图上？
答案 0 :(得分：5)
您不能同时显示相机预览并使用画布进行绘制。你必须做其中一个。