在滑动菜单的时候,有时需要快速的滑动条件下,才显示菜单,如人人的侧滑
Android提供一个类来实现测速 : VelocityTracker
private VelocityTracker mVelocityTracker = null;
private void addVelocityTrackerEvent(MotionEvent event) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
}
// 获得横向的手速
private int getTouchVelocityX() {
if (mVelocityTracker == null)
return 0;
mVelocityTracker.computeCurrentVelocity(1000);
int velocity = (int) mVelocityTracker.getXVelocity();
return Math.abs(velocity);
}
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
addVelocityTrackerEvent(event);
return false;
}
调用getTouchVelocityX方法即可获得手指的滑动速度,如果值大于200,就很快了。