@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (listener != null) {
listener.onScrollChanged(this, l, t, oldl, oldt);
}
}
@Override
public void computeScroll() {
if (scroller.computeScrollOffset()) {
if (this.onScrollChangedListener != null) {
onScrollChangedListener.OnHorizontalScrollChanged(
this, SCROLLING, scroller.getCurrX() - offX);
onScrollChangedListener.OnVerticalScrollChanged(
this, SCROLLING, scroller.getCurrY() - offY);
}
offX = scroller.getCurrX();
offY = scroller.getCurrY();
invalidate();
} else {
if (scrolling) {
if (this.onScrollChangedListener != null) {
onScrollChangedListener.OnHorizontalScrollChanged(this, SCROLL_END, 0);
onScrollChangedListener.OnVerticalScrollChanged(this, SCROLL_END, 0);
}
scrolling = false;
}
}
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
listener.onScrollChanged(l, t, oldl, oldt);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
super.onTouchEvent(event);
if (velocityTracker == null) velocityTracker = VelocityTracker.obtain();
velocityTracker.addMovement(event);
if (event.getAction() == MotionEvent.ACTION_DOWN) {
if (!scroller.isFinished()) scroller.abortAnimation();
lastX = event.getX();
lastY = event.getY();
draggingX = draggingY = false;
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
if (draggingX || Math.abs(event.getX() - lastX) > touchSlop) {
this.offX += (event.getX() - lastX);
if (this.getWidth() > worldWidth) offX = 0;
else if (offX > 0) offX = 0;
else if (offX < this.getWidth() - worldWidth) offX = this.getWidth() - worldWidth;
if (!draggingX) {
if (this.onScrollChangedListener != null)
onScrollChangedListener.OnHorizontalScrollChanged(
this, SCROLL_START, (int) (event.getX() - lastX));
} else {
if (this.onScrollChangedListener != null)
onScrollChangedListener.OnHorizontalScrollChanged(
this, SCROLLING, (int) (event.getX() - lastX));
}
lastX = event.getX();
draggingX = true;
}
if (draggingY || Math.abs(event.getY() - lastY) > touchSlop) {
this.offY += (event.getY() - lastY);
if (this.getHeight() > worldHeight) offY = 0;
else if (offY > 0) offY = 0;
else if (offY < this.getHeight() - worldHeight) offY = this.getHeight() - worldHeight;
if (!draggingY) {
if (this.onScrollChangedListener != null)
onScrollChangedListener.OnVerticalScrollChanged(
this, SCROLL_START, (int) (event.getY() - lastY));
} else {
if (this.onScrollChangedListener != null)
onScrollChangedListener.OnVerticalScrollChanged(
this, SCROLLING, (int) (event.getY() - lastY));
}
lastY = event.getY();
draggingY = true;
}
if (draggingX || draggingY) this.invalidate();
} else if (event.getAction() == MotionEvent.ACTION_UP
|| event.getAction() == MotionEvent.ACTION_CANCEL) {
velocityTracker.computeCurrentVelocity(1000, maximumVelocity);
float vx = velocityTracker.getXVelocity();
float vy = velocityTracker.getYVelocity();
int minX, minY;
boolean flip = false;
float minTan = 3.0f;
// 当斜率大于minTan时忽略小方向的速度
if (Math.abs(vx) < minimumVelocity
|| this.getWidth() > worldWidth
|| Math.abs(vy / vx) > minTan) {
vx = 0;
if (this.getWidth() > worldWidth) minX = 0;
else minX = this.getWidth() - worldWidth;
} else {
minX = this.getWidth() - worldWidth;
flip = true;
}
if (Math.abs(vy) < minimumVelocity
|| this.getHeight() > worldHeight
|| Math.abs(vx / vy) > minTan) {
vy = 0;
if (this.getHeight() > worldHeight) minY = 0;
else minY = this.getHeight() - worldHeight;
} else {
minY = this.getHeight() - worldHeight;
flip = true;
}
if (flip) {
scrolling = true;
scroller.fling(offX, offY, (int) vx, (int) vy, minX, 0, minY, 0);
this.invalidate();
} else {
if (this.onScrollChangedListener != null) {
if (draggingX) {
onScrollChangedListener.OnHorizontalScrollChanged(this, SCROLL_END, 0);
}
if (draggingY) {
onScrollChangedListener.OnVerticalScrollChanged(this, SCROLL_END, 0);
}
}
}
draggingX = draggingY = false;
velocityTracker.recycle();
velocityTracker = null;
this.invalidate();
}
return true;
}
