前言
看过前两篇文章的同学
sidhu眼中的CoordinatorLayout.Behavior&＃xff08;一&＃xff09;
sidhu眼中的CoordinatorLayout.Behavior&＃xff08;二&＃xff09;
应该知道今天要讲的内容了——Behavior的布局依赖
其实这个内容挺少的&＃xff0c;我都想直接贴代码然大家自己体会了……额&＃xff0c;开玩笑的&＃xff0c;不过内容真的少&＃xff0c;我也不浪费大家时间了&＃xff0c;疑问我不提了&＃xff0c;直入主题
主题
&＃xff08;有木有直入主题&＃xff0c;哈哈~&＃xff09;
我将上次的例子做了下修改
xml&＃xff1a;
相比于之前的布局我们可以看到&＃xff0c;就多了一个小方块在布局里面&＃xff0c;至于我想实现的效果可以看下面效果图
让小方块可以随着上面的head做同步的位移
就如我上篇所说的&＃xff0c;使用原理还是实现NestedScrollingChild接口&＃xff0c;废话不多说&＃xff0c;上代码&＃xff08;没错&＃xff0c;我就是这样的人&＃xff0c;一言不合就上代码&＃xff09;
package com.mintmedical.mybehaviordemo;import android.animation.ValueAnimator;
import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.view.NestedScrollingChild;
import android.support.v4.view.NestedScrollingChildHelper;
import android.util.AttributeSet;
import android.view.View;/*** Created by SidHu on 2016/8/17.*/
public class HideHeadBehavior extends CoordinatorLayout.Behavior implements NestedScrollingChild {private boolean isHeadHide &＃61; false;private boolean isAnimating &＃61; false;private final int SCROOL_VALUE &＃61; 50;private int childHeight;private final int animationDuration &＃61; 500;private NestedScrollingChildHelper childHelper;public HideHeadBehavior(Context context, AttributeSet attrs) {super(context, attrs);}&＃64;Overridepublic boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {if (target.getId() &＃61;&＃61; R.id.rel_body) {if (childHeight &＃61;&＃61; 0) {childHeight &＃61; child.getHeight();}if (childHelper &＃61;&＃61; null) {childHelper &＃61; new NestedScrollingChildHelper(child);}return true;} else {return false;}}&＃64;Overridepublic void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dx, int dy, int[] consumed) {super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);if (isAnimating) {return;}if (dy > SCROOL_VALUE && !isHeadHide) {hide(child, target);} else if (dy <-SCROOL_VALUE && isHeadHide) {show(child, target);}}public void hide(final View child, final View target) {isHeadHide &＃61; true;ValueAnimator valueAnimator &＃61; new ValueAnimator();valueAnimator.setIntValues(0, childHeight);valueAnimator.setDuration(animationDuration);valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {&＃64;Overridepublic void onAnimationUpdate(ValueAnimator animation) {if (child.getBottom() > 0) {int value &＃61; (int) animation.getAnimatedValue();isAnimating &＃61; value !&＃61; childHeight;child.layout(child.getLeft(), -value, child.getRight(), -value &＃43; childHeight);target.layout(target.getLeft(), -value &＃43; childHeight, target.getRight(), target.getBottom());}}});valueAnimator.start();}public void show(final View child, final View target) {isHeadHide &＃61; false;ValueAnimator valueAnimator &＃61; new ValueAnimator();valueAnimator.setIntValues(0, childHeight);valueAnimator.setDuration(animationDuration);valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {&＃64;Overridepublic void onAnimationUpdate(ValueAnimator animation) {if (child.getBottom()
我将head实现了NestedScrollingChild接口&＃xff0c;然后就没有做其他事情了。&＃xff08;这也说明了&＃xff0c;想让控件通知CoordinatorLayout自己的状态其实只要实现了NestedScrollingChild接口就够了&＃xff0c;假如你不需要关心滑动手势&＃xff0c;就像小方块只关心head的位移一样&＃xff0c;那你startNestedScroll之类的这样方法都不用要了&＃xff09;
那我们看一下小方块的Behavior
package com.mintmedical.mybehaviordemo;import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.view.View;/*** Created by SidHu on 2016/8/18.*/
public class MoveWithHeadBehavior extends CoordinatorLayout.Behavior{private int lastBottom &＃61; -1;public MoveWithHeadBehavior(Context context, AttributeSet attrs) {super(context, attrs);}&＃64;Overridepublic boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {return dependency.getId() &＃61;&＃61; R.id.rel_head;}&＃64;Overridepublic boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {if (lastBottom &＃61;&＃61; -1) {lastBottom &＃61; dependency.getBottom();}if (dependency.getBottom() !&＃61; lastBottom) {int d &＃61; dependency.getBottom()-lastBottom;lastBottom &＃61; dependency.getBottom();child.offsetTopAndBottom(d);}return super.onDependentViewChanged(parent, child, dependency);}
}
代码也是非~非~非~非常简单&＃xff0c;布局依赖最主要的关系这两个方法&＃xff0c;一个是判断是不是自己关心的target View&＃xff08;跟滑动的时候简直一毛一样&＃xff09;&＃xff0c;一个是被关心的target View变化以后的回调&＃xff0c;代码我就不解释啦&＃xff0c;也是很简单&＃xff08;大家有什么问题可以在评论里面问我啊&＃xff09;。
好了&＃xff0c;关于Behavior的使用我就先介绍到这了
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