android自定义相机加取景框

这是预览效果

1、首先，xml布局，两个控件。SurfaceView和MyView

<SurfaceView
    android:id="@+id/surfaceView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<com.example.administrator.myapplication.MyView
    android:id="@+id/myView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

SurfaceView是相机预览控件，系统相机默认是横屏的，所以，要么我们把相机旋转90度，要么我们把屏幕设置成横屏

camera.setDisplayOrientation(90);//相机旋转90度

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//把屏幕设置成横屏

2、创建MyActivity。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//把屏幕设置成横屏
  setContentView(R.layout.testlayout);
    myView = (MyView) findViewById(R.id.myView);
    surfaceview = (SurfaceView) findViewById(R.id.surfaceView);
    surfaceview.setOnTouchListener(new View.OnTouchListener() {
        //点击 surfaceview 聚焦
    @Override
        public boolean onTouch(View v, MotionEvent event) {
            camera.autoFocus(myAutoFocusCallback);
            return false;
        }
    });

private MyView myView;
private Camera camera;
private SurfaceView surfaceview;
private Camera.AutoFocusCallback myAutoFocusCallback = new Camera.AutoFocusCallback() {
    @Override
    public void onAutoFocus(boolean success, Camera camera) {  

             //聚焦后的操作

}} ; SurfaceHolder holder = surfaceview.getHolder() ; holder.setKeepScreenOn( true) ; // 屏幕常亮 holder.addCallback( new MySurfaceCallback()) ; holder.lockCanvas() ;}

private final class MySurfaceCallback implements SurfaceHolder.Callback {

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {

           //当surface的格式或大小发生改变，这个方法就被调用

  } @Override public void surfaceCreated(SurfaceHolder holder) { try { // surfaceview 创建之后，就去打开相机 camera = Camera. open() ; Camera.Parameters params = camera.getParameters() ; camera.setPreviewDisplay( surfaceview.getHolder()) ; camera.startPreview() ; } catch (IOException e) { e.printStackTrace() ; } } @Override public void surfaceDestroyed(SurfaceHolder holder) { if ( camera != null) { camera.release() ; camera = null; } }}
3、还有一个方法，点击拍摄的时候调用

camera.takePicture(null, null, myPictureCallback);

private Camera.PictureCallback myPictureCallback = new Camera.PictureCallback(){
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        //保存图片
    }
};

4、最后是MyView

public class MyView extends ImageView {

    //获取屏幕的宽和高。根据屏幕的宽和高来算取景框的位置
    private int width, height;
    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
        width = wm.getDefaultDisplay().getWidth();
        height = wm.getDefaultDisplay().getHeight();
    }

    @Override
    public void onDraw(Canvas canvas) {
        Paint paint = new Paint();
        paint.setColor(Color.RED);
        paint.setAlpha(250);
        // 下面是取景框的8条线
        // xy的算法是：把屏幕横着(逆时针旋转90度的屏幕)，从左到右是x轴，从上到下是y轴
        canvas.drawLine(200, 150, 300, 150, paint);
        canvas.drawLine(200, 150, 200, 200, paint);

        canvas.drawLine(200, height-150, 300, height-150, paint);
        canvas.drawLine(200, height-150, 200, height-200, paint);

        canvas.drawLine(width-355, 150, width-455, 150, paint);
        canvas.drawLine(width-355, 150, width-355, 200, paint);

        canvas.drawLine(width-355, height-150, width-455, height-150, paint);
        canvas.drawLine(width-355, height-150, width-355, height-200, paint);
        super.onDraw(canvas);
    }
}