仅用一根手指而不是两只手指来调整ImageView的大小

debugcn 发表于 Dev

杰森

我试图用一个手指移动（上下）来更改ImageView的高度。下面的代码用两根手指改变高度（例如捏或反向）。如何修改此代码以执行我想要的操作？谢谢。

public class MainActivity extends Activity {


    private  ImageView iv;
    private  Matrix matrix = new Matrix();
    private float scale = 1f;
    private ScaleGestureDetector SGD;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        iv = iv=(ImageView)findViewById(R.id.imageView);
        SGD = new ScaleGestureDetector(this, new ScaleListener());

    }

    public boolean onTouchEvent(MotionEvent ev) {
        SGD.onTouchEvent(ev);
        return true;
    }

    private class  ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener
    {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            scale *= detector.getScaleFactor();
            scale = Math.max(0.1f, Math.min(scale, 5.0f));

            matrix.setScale(1, scale);
            iv.setImageMatrix(matrix);
            return true;
        }
    }
}

冰激凌

使用GestureDetector进行滚动：

@Bind(R.id.container)
ViewGroup container;

@Bind(R.id.image)
ImageView image;
private GestureDetectorCompat detector;
private float yscale = 1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    ButterKnife.bind(this);
    image.setScaleType(ImageView.ScaleType.MATRIX);

    detector = new GestureDetectorCompat(this, new GestureDetector.SimpleOnGestureListener() {

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            Matrix m = new Matrix();
            yscale += distanceY / container.getHeight();
            m.setScale(1, yscale, 0, 0);
            image.setImageMatrix(m);
            return true;
        }
    });
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    return detector.onTouchEvent(event);
} detector.onTouchEvent(event);
}

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