import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.ScrollView;
public class MyScrollView extends ScrollView {
private static final int size = 4;
private View inner;
private float y;
private Rect normal = new Rect();
public MyScrollView(Context context) {
super(context);
}
public MyScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
if (getChildCount() > 0) {
inner = getChildAt(0);
}
}
@Override
public boolean canScrollVertically(int direction) {
return true;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (inner == null) {
return super.onTouchEvent(ev);
} else {
commOnTouchEvent(ev);
}
return super.onTouchEvent(ev);
}
public void commOnTouchEvent(MotionEvent ev) {
int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
y = ev.getY();
break;
case MotionEvent.ACTION_UP:
if (isNeedAnimation()) {
animation();
}
break;
case MotionEvent.ACTION_MOVE:
final float preY = y;
float nowY = ev.getY();
int deltaY = (int) (preY - nowY) / size;
y = nowY;
if (isNeedMove()) {
if (normal.isEmpty()) {
normal.set(inner.getLeft(), inner.getTop(), inner.getRight(), inner.getBottom());
}
else {
inner.layout(inner.getLeft(), inner.getTop() - deltaY, inner.getRight(), inner.getBottom() - deltaY);
}
}
break;
default:
break;
}
}
public void animation() {
TranslateAnimation move = new TranslateAnimation(0, 0, inner.getTop(), normal.top);
move.setDuration(200);
inner.startAnimation(move);
inner.layout(normal.left, normal.top, normal.right, normal.bottom);
normal.setEmpty();
}
public boolean isNeedAnimation() {
return !normal.isEmpty();
}
public boolean isNeedMove() {
int offset = inner.getMeasuredHeight() - getHeight();
int scrollY = getScrollY();
if (scrollY == 0 || scrollY == offset) {
return true;
}
return false;
}
}
|