大家好,眾所周知,android裡兩個相同方向的ScrollView是不能嵌套的,那要是有這樣的需求怎麼辦?(這個需求一般都是不懂android的人提出來的)
難道就真的不能嵌套嗎?當然可以,只要你再寫一個ScrollView,在裡面做點腳,它就支持嵌套了。
目前做的這個只支持兩個ScrollView嵌套,兩個以上還有待改進,能套兩個就已經能滿足很多需求了,呵呵,另外現在只做了縱向scrollview的支持,橫向的還沒來的急做哦。
效果截圖:
先上核心代碼吧。代碼裡頭我加了注釋,方便大家閱讀
代碼如下:
package com.sun.shine.study.innerscrollview.view;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ScrollView;
public class InnerScrollView extends ScrollView {
/**
*/
public ScrollView parentScrollView;
public InnerScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
private int lastScrollDelta = 0;
public void resume() {
overScrollBy(0, -lastScrollDelta, 0, getScrollY(), 0, getScrollRange(), 0, 0, true);
lastScrollDelta = 0;
}
int mTop = 10;
/**
* 將targetView滾到最頂端
*/
public void scrollTo(View targetView) {
int oldScrollY = getScrollY();
int top = targetView.getTop() - mTop;
int delatY = top - oldScrollY;
lastScrollDelta = delatY;
overScrollBy(0, delatY, 0, getScrollY(), 0, getScrollRange(), 0, 0, true);
}
private int getScrollRange() {
int scrollRange = 0;
if (getChildCount() > 0) {
View child = getChildAt(0);
scrollRange = Math.max(0, child.getHeight() - (getHeight()));
}
return scrollRange;
}
int currentY;
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (parentScrollView == null) {
return super.onInterceptTouchEvent(ev);
} else {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
// 將父scrollview的滾動事件攔截
currentY = (int)ev.getY();
setParentScrollAble(false);
return super.onInterceptTouchEvent(ev);
} else if (ev.getAction() == MotionEvent.ACTION_UP) {
// 把滾動事件恢復給父Scrollview
setParentScrollAble(true);
} else if (ev.getAction() == MotionEvent.ACTION_MOVE) {
}
}
return super.onInterceptTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
View child = getChildAt(0);
if (parentScrollView != null) {
if (ev.getAction() == MotionEvent.ACTION_MOVE) {
int height = child.getMeasuredHeight();
height = height - getMeasuredHeight();
// System.out.println("height=" + height);
int scrollY = getScrollY();
// System.out.println("scrollY" + scrollY);
int y = (int)ev.getY();
// 手指向下滑動
if (currentY < y) {
if (scrollY <= 0) {
// 如果向下滑動到頭,就把滾動交給父Scrollview
setParentScrollAble(true);
return false;
} else {
setParentScrollAble(false);
}
} else if (currentY > y) {
if (scrollY >= height) {
// 如果向上滑動到頭,就把滾動交給父Scrollview
setParentScrollAble(true);
return false;
} else {
setParentScrollAble(false);
}
}
currentY = y;
}
}
return super.onTouchEvent(ev);
}
/**
* 是否把滾動事件交給父scrollview
*
* @param flag
*/
private void setParentScrollAble(boolean flag) {
parentScrollView.requestDisallowInterceptTouchEvent(!flag);
}
}