在Android 的Camera 预览上执行 Drawing 操作

来自anddev

import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.hardware.Camera; import android.os.Bundle; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.Window; import android.view.ViewGroup.LayoutParams; public class TestCameraOverlay extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); Preview mPreview = new Preview(this); DrawOnTop mDraw = new DrawOnTop(this); setContentView(mPreview); addContentView(mDraw, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); } } class DrawOnTop extends View { public DrawOnTop(Context context) { super(context); // TODO Auto-generated constructor stub } @Override protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub Paint paint = new Paint(); paint.setStyle(Paint.Style.FILL); paint.setColor(Color.BLACK); canvas.drawText("Test Text", 10, 10, paint); super.onDraw(canvas); } } class Preview extends SurfaceView implements SurfaceHolder.Callback { SurfaceHolder mHolder; Camera mCamera; Preview(Context context) { super(context); // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } public void surfaceCreated(SurfaceHolder holder) { // The Surface has been created, acquire the camera and tell it where // to draw. mCamera = Camera.open(); mCamera.setPreviewDisplay(holder); } public void surfaceDestroyed(SurfaceHolder holder) { // Surface will be destroyed when we return, so stop the preview. // Because the CameraDevice object is not a shared resource, it's very // important to release it when the activity is paused. mCamera.stopPreview(); mCamera = null; } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { // Now that the size is known, set up the camera parameters and begin // the preview. Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(w, h); mCamera.setParameters(parameters); mCamera.startPreview(); } } Parsed in 0.113 seconds, using GeSHi 1.0.8.4

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