我正在尝试实现捏合以放大 Android 上的列表视图，当我单击并拖动缩放的列表视图时遇到问题。首先，这是代码：
public class ScaleListView extends ListView {
private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;
private float x = 0;
private float y = 0;
private float startx = 0;
private float starty = 0;
private boolean canClick = true;
private float xtranslation = 0;
public ScaleListView(Context context, AttributeSet attrs) {
super(context, attrs);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
startx = ev.getX();
starty = ev.getY();
}
if (ev.getPointerCount() > 1) {
y = ev.getY();
x = ev.getX();
} else if (ev.getAction() == MotionEvent.ACTION_UP) {
canClick = (ev.getX() - startx) == 0 && (ev.getY() - starty) == 0 && mScaleFactor == 1;
} else if(ev.getAction() == MotionEvent.ACTION_MOVE){
xtranslation = ev.getX() - startx;
}
mScaleDetector.onTouchEvent(ev);
return super.onTouchEvent(ev);
}
@Override
public void onDraw(Canvas canvas) {
canvas.scale(mScaleFactor, mScaleFactor, x , y);
canvas.translate(xtranslation, 0);
super.onDraw(canvas);
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScale(ScaleGestureDetector detector) {
canClick = false;
mScaleFactor *= detector.getScaleFactor();
// Don't let the object get too small or too large.
mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f));
if (mScaleFactor <= 1) {
mScaleFactor = 1;
canClick = true;
}
xPos = ScaleListView.this.getWidth() - detector.getFocusX();
ScaleListView.this.invalidate();
return true;
}
}
public boolean canClick(){
return canClick;
}
问题在于翻译。它是无限的，我可以水平拖动它并将列表视图从视口中取出。所以我无法面对如何在翻译中占据优势......感谢您的帮助。