标签:android
一个Android手势缩放图片的工具类;同时,此类还实现另外一个功能:当手指按在触屏上移动时候,图片“黏贴”在手指上随手指移动而整体移动。
具体使用方法可以是这样:先new一个此类的实例,然后在ImageView的方法setOnTouchListener(new ImageViewOnMultiTouchListener());
例如:
ImageViewOnMultiTouchListener listener=new ImageViewOnMultiTouchListener(); ImageView mImageView=(ImageView)findViewById(R.id.imageView); mImageView.setOnTouchListener(listener);
ImageViewOnMultiTouchListener.java全部源代码:
public class ImageViewOnMultiTouchListener implements View.OnTouchListener { private final int NONE = 0; private final int MOVE = 1; private final int ZOOM = 2; private final int DRAG = 3; private int mode = NONE; private Matrix matrix = new Matrix(); private Matrix savedMatrix = new Matrix(); private PointF start = new PointF(); private PointF mid = new PointF(); private float oldDistance = 0; @Override public boolean onTouch(View v, MotionEvent event) { ImageView view = (ImageView) v; switch (event.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: matrix.set(view.getImageMatrix()); savedMatrix.set(matrix); start.set(event.getX(), event.getY()); mode = DRAG; break; case MotionEvent.ACTION_POINTER_DOWN: oldDistance = spacing(event); if (oldDistance > 5f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; } break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_POINTER_UP: mode = NONE; break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { matrix.set(savedMatrix); matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); } else if (mode == ZOOM) { float newDist = spacing(event); if (newDist > 5f) { matrix.set(savedMatrix); float scale = newDist / oldDistance; matrix.postScale(scale, scale, mid.x, mid.y); } } break; } view.setImageMatrix(matrix); view.setScaleType(ImageView.ScaleType.MATRIX); view.setPadding(3, 5, 3, 5); return true; } private float spacing(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } private void midPoint(PointF point, MotionEvent event) { float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); } }
标签:android
原文地址:http://blog.csdn.net/zhangphil/article/details/43965701