[英]How to pinch zoom in fragment android
如何实现片段中的收缩缩放图像?
我有以下用于放大图像的代码:
ImageView imageDetail;
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
PointF startPoint = new PointF();
PointF midPoint = new PointF();
float oldDist = 1f;
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
imageDetail = (ImageView) findViewById(R.id.imageView1);
/**
* set on touch listner on image
*/
imageDetail.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
System.out.println("matrix=" + savedMatrix.toString());
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
startPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(midPoint, 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() - startPoint.x, event.getY() - startPoint.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, midPoint.x, midPoint.y);
}
}
break;
}
view.setImageMatrix(matrix);
return true;
}
@SuppressLint("FloatMath")
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);
}
});
上面的代码对活动有效,但对片段无效。 请帮忙! 急需!
您需要更改此行
imageDetail = (ImageView) findViewById(R.id.imageView1);
为此
imageDetail = (ImageView) rootView.findViewById(R.id.imageView1);
其中rootView是您为片段中的View赋予的名称(通常是rootview)
我必须将图像视图的比例类型设置为“矩阵”:
imgView.setScaleType(ImageView.ScaleType.MATRIX);
按照此链接:
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