filing 到头的时候展开 head

csnowstack · csnowstack · commit 803924b6d8e8 · 2016-12-15T17:26:08.000+08:00
diff --git a/README.md b/README.md
@@ -2,6 +2,8 @@
 
 ### 简介
 
+[项目地址](https://github.com/CSnowStack/BehaviorDemo)
+
 #### 建议
 请先阅读[这篇文章](http://www.jianshu.com/p/f7989a2a3ec2)
 > 好多东西抄自这里
@@ -17,13 +19,11 @@
 
 ![实现的效果](https://github.com/CSnowStack/BehaviorDemo/blob/master/img/c.gif)
 
-[项目地址](https://github.com/CSnowStack/BehaviorDemo)
 
-> 一些细节没有实现 ,见谅,录制的gif效果也不太好 :-(
 
 
-### TODO
-- 快速滑动会产生问题.....
+> 一些细节没有实现 ,见谅,录制的gif效果也不太好 :-(
+
 
 ### 实现
 
@@ -50,42 +50,79 @@
 
 - `ToolBarIcon` 跟随`BGContent` ,根据`BGContent`移动的比例修改图标的`Alpha`
 
-
 #### 部分代码
 
 ```java
 //TabBehavior
-@Override
 public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dx, int dy, int[] consumed) {
     super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
-    //只要开始拦截，就需要把所有Scroll事件消费掉
-    consumed[1]=dy;
-    int distance=-dy/2;//降低移动的速度
-    mUp=dy>0;
-
-    if(child.getTranslationY()+distance<-mMaxDistance){
-        distance=-mMaxDistance;
-    }else if(child.getTranslationY()+distance>0){
-        distance=0;
-    }else {
-      distance= (int) (child.getTranslationY()+distance);
+
+    if(isChildRequestScroll(child.getTranslationY())){//如果list需要滑动这边就不动
+        consumed[1]=0;
+        return;
+    }
+
+    consumed[1]=dy;//全部消耗
+    int distance = -dy / 2;//降低移动的速度
+    mUp = dy > 0;
+
+    if (child.getTranslationY() + distance < -mMaxDistance) {
+        distance = -mMaxDistance;
+    } else if (child.getTranslationY() + distance > 0) {
+        distance = 0;
+    } else {
+        distance = (int) (child.getTranslationY() + distance);
     }
     child.setTranslationY(distance);
 }
 
-//ListBehavior
+/**
+ * Child是否需要滑动
+ */
+private boolean isChildRequestScroll(float  translationY) {
+    return (translationY == -mMaxDistance &&//在顶部
+                    mViewPager.getAdapter() != null && //有适配器
+                    mViewPager.getAdapter().getCount() > 0 &&//有item
+                    mViewPager.getAdapter() instanceof IsChildRequestScrollListener && //实现了
+                    ((IsChildRequestScrollListener) mViewPager.getAdapter()).requestScroll()//需要滑动
+            );
+}
+
+
+//设置 listener 检测是否需要展开
 @Override
-int getScrollRange(View v) {
-    if (isDependOn(v)) {
-        return -mHeightToolbar;
-    } else {
-        return super.getScrollRange(v);
-    }
+public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
+    mControlChange=true;
+
+    if(mViewPager.getAdapter() != null && //有适配器
+            mViewPager.getAdapter().getCount() > 0 &&//有item
+            mViewPager.getAdapter() instanceof SupportNeedExpendListener&&
+           ((SupportNeedExpendListener) mViewPager.getAdapter()).getNeedExpendListener()==null){
+       ((SupportNeedExpendListener) mViewPager.getAdapter()).setNeedExpendListener(this);
+   }
+    return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
 }
-//   HeaderScrollingViewBehavior$onMeasure  所以要返回 - mHeightToolbar
-final int height = availableHeight - header.getMeasuredHeight()
-        + getScrollRange(header);
 
+/**
+  * list fling到头的时候 展开
+  */
+ @Override
+ public void needExpand() {
+     if(!mControlChange){//如果是手指在控制就不管
+         mValueAnimator.setDuration(500);
+         mValueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
+             @Override
+             public void onAnimationUpdate(ValueAnimator animation) {
+                 mTab.setTranslationY((animation.getAnimatedFraction()-1)*mMaxDistance);
+             }
+         });
+         mValueAnimator.start();
+     }
+ }
 ```
 
->代码是蛮简单的 ,直接看项目即可,就那几行代码
+>代码是蛮简单的 ,直接看项目即可,就那几行代码, 又加看点功能 耦合度变高了的感觉欢迎 Star,提 issue 还有PR
+
+
+### TODO
+- 在向上fling的过程中,向下滑,会出现错乱的情况 :-(
diff --git a/app/src/main/java/cq/behaviordemo/ItemFragment.java b/app/src/main/java/cq/behaviordemo/ItemFragment.java
@@ -10,15 +10,18 @@
 import android.view.ViewGroup;
 
 import cq.behaviordemo.adapter.FriendInfoAdapter;
+import cq.behaviordemo.listener.IsChildRequestScrollListener;
+import cq.behaviordemo.listener.NeedExpandListener;
+import cq.behaviordemo.listener.SupportNeedExpendListener;
 
 /**
  * Created by cqll on 2016/9/30.
  */
 
-public class ItemFragment extends Fragment implements IsChildRequestScrollListener{
+public class ItemFragment extends Fragment implements IsChildRequestScrollListener ,SupportNeedExpendListener{
 
     private RecyclerView mRecyclerView;
-
+    private NeedExpandListener mNeedExpandListener;
     public static ItemFragment newInstance() {
 
         Bundle args = new Bundle();
@@ -39,6 +42,21 @@ public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
     private void initView() {
         mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
         mRecyclerView.setAdapter(new FriendInfoAdapter());
+        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
+                super.onScrollStateChanged(recyclerView, newState);
+            }
+
+            @Override
+            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+                super.onScrolled(recyclerView, dx, dy);
+                if(dy<0&&((LinearLayoutManager)recyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition()==0){
+                    if(mNeedExpandListener!=null)
+                        mNeedExpandListener.needExpand();
+                }
+            }
+        });
     }
 
 
@@ -50,4 +68,15 @@ public boolean requestScroll() {
                 mRecyclerView.getAdapter().getItemCount()>0&&
                 ((LinearLayoutManager)mRecyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition()==0);
     }
+
+
+    @Override
+    public void setNeedExpendListener(NeedExpandListener listener) {
+        mNeedExpandListener=listener;
+    }
+
+    @Override
+    public NeedExpandListener getNeedExpendListener() {
+        return mNeedExpandListener;
+    }
 }
diff --git a/app/src/main/java/cq/behaviordemo/adapter/ItemAdapter.java b/app/src/main/java/cq/behaviordemo/adapter/ItemAdapter.java
@@ -9,28 +9,33 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import cq.behaviordemo.IsChildRequestScrollListener;
+import cq.behaviordemo.listener.IsChildRequestScrollListener;
 import cq.behaviordemo.ItemFragment;
+import cq.behaviordemo.listener.NeedExpandListener;
+import cq.behaviordemo.listener.SupportNeedExpendListener;
 
 /**
  * Created by cqll on 2016/12/15.
  */
 
-public  class ItemAdapter extends FragmentStatePagerAdapter implements IsChildRequestScrollListener{
+public  class ItemAdapter extends FragmentStatePagerAdapter implements IsChildRequestScrollListener,SupportNeedExpendListener{
     private String [] titles={"MEDIA","ABOUT","REVIEWS"};
     private WeakReference<ViewPager> mViewPager;//也许有点用
     private List<ItemFragment> mFragments;
+    private NeedExpandListener mNeedExpandListener;
     public ItemAdapter(FragmentManager fm) {
         this(fm,null);
     }
 
     public ItemAdapter(FragmentManager fm, ViewPager viewPager) {
         super(fm);
         mViewPager = new WeakReference<ViewPager>(viewPager);
+
         mFragments=new ArrayList<ItemFragment>();
         mFragments.add(ItemFragment.newInstance());
         mFragments.add(ItemFragment.newInstance());
         mFragments.add(ItemFragment.newInstance());
+        fillListener();
     }
 
     @Override
@@ -61,4 +66,25 @@ public boolean requestScroll() {
 
         return false;
     }
+
+    @Override
+    public void setNeedExpendListener(NeedExpandListener listener) {
+        mNeedExpandListener=listener;
+        fillListener();
+    }
+
+    @Override
+    public NeedExpandListener getNeedExpendListener() {
+        return mNeedExpandListener;
+    }
+
+    private void fillListener(){
+        if(mFragments.size()>0){
+            for(Fragment fragment:mFragments){
+                if(fragment instanceof SupportNeedExpendListener &&((SupportNeedExpendListener)fragment).getNeedExpendListener()==null){
+                    ((SupportNeedExpendListener)fragment).setNeedExpendListener(mNeedExpandListener);
+                }
+            }
+        }
+    }
 }
diff --git a/app/src/main/java/cq/behaviordemo/behavior/TabBehavior.java b/app/src/main/java/cq/behaviordemo/behavior/TabBehavior.java
@@ -9,20 +9,22 @@
 import android.view.View;
 
 import cq.behaviordemo.Constants;
-import cq.behaviordemo.IsChildRequestScrollListener;
 import cq.behaviordemo.R;
+import cq.behaviordemo.listener.IsChildRequestScrollListener;
+import cq.behaviordemo.listener.NeedExpandListener;
+import cq.behaviordemo.listener.SupportNeedExpendListener;
 
 /**
  * Created by cqll on 2016/12/9.
  */
 
-public class TabBehavior extends CoordinatorLayout.Behavior {
+public class TabBehavior extends CoordinatorLayout.Behavior implements NeedExpandListener {
     private int mHeightToolbar, mMaxDistance, mEditorPadding;
     private Context mContext;
-    private boolean mUp/*向上滑动,还是向下滑动*/;
+    private boolean mUp/*向上滑动,还是向下滑动*/,mControlChange/*手指控制的滑动*/;
     private ValueAnimator mValueAnimator;
     private ViewPager mViewPager;
-
+    private View mTab;
     public TabBehavior() {
     }
 
@@ -33,8 +35,6 @@ public TabBehavior(Context context, AttributeSet attrs) {
         mEditorPadding = context.getResources().getDimensionPixelOffset(R.dimen.editor_padding);
 
         mValueAnimator = ValueAnimator.ofFloat(0, 1);
-
-
     }
 
 
@@ -48,6 +48,7 @@ public TabBehavior(Context context, AttributeSet attrs) {
     @Override
     public boolean onLayoutChild(CoordinatorLayout parent, View child, int layoutDirection) {
         parent.onLayoutChild(child, layoutDirection);
+        mTab=child;
         mViewPager = (ViewPager) parent.findViewById(R.id.viewpager);
         mMaxDistance = (int) (child.getWidth() * Constants.FRACTION_WIDTH_BGCONTENT * 0.64f + mContext.getResources().getDimensionPixelOffset(R.dimen.img_icon_height_start) / 2 + child.getWidth() * Constants.FRACTION_PADDING + mEditorPadding);
         child.offsetTopAndBottom(mMaxDistance + mHeightToolbar);
@@ -57,8 +58,15 @@ public boolean onLayoutChild(CoordinatorLayout parent, View child, int layoutDir
 
     @Override
     public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
+        mControlChange=true;
+
+        if(mViewPager.getAdapter() != null && //有适配器
+                mViewPager.getAdapter().getCount() > 0 &&//有item
+                mViewPager.getAdapter() instanceof SupportNeedExpendListener&&
+               ((SupportNeedExpendListener) mViewPager.getAdapter()).getNeedExpendListener()==null){
+           ((SupportNeedExpendListener) mViewPager.getAdapter()).setNeedExpendListener(this);
+       }
         return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
-
     }
 
 
@@ -69,11 +77,11 @@ public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View chi
     public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dx, int dy, int[] consumed) {
         super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
 
-        if(isChildRequestScroll(child)){//如果list需要滑动这边就不动
+        if(isChildRequestScroll(child.getTranslationY())){//如果list需要滑动这边就不动
             consumed[1]=0;
             return;
         }
-        //只要开始拦截，就需要把所有Scroll事件消费掉
+
         consumed[1]=dy;//全部消耗
         int distance = -dy / 2;//降低移动的速度
         mUp = dy > 0;
@@ -92,6 +100,7 @@ public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, V
     @Override
     public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, View child, View target) {
         super.onStopNestedScroll(coordinatorLayout, child, target);
+        mControlChange=false;
         float translationY = child.getTranslationY();
         if (Math.abs(translationY) == mMaxDistance || translationY == 0) {
             return;
@@ -131,12 +140,33 @@ public void onAnimationUpdate(ValueAnimator animation) {
     }
 
 
-    private boolean isChildRequestScroll(View tab) {
-        return (tab.getTranslationY() == -mMaxDistance &&//在顶部
+    /**
+     * Child是否需要滑动
+     */
+    private boolean isChildRequestScroll(float  translationY) {
+        return (translationY == -mMaxDistance &&//在顶部
                         mViewPager.getAdapter() != null && //有适配器
                         mViewPager.getAdapter().getCount() > 0 &&//有item
                         mViewPager.getAdapter() instanceof IsChildRequestScrollListener && //实现了
                         ((IsChildRequestScrollListener) mViewPager.getAdapter()).requestScroll()//需要滑动
                 );
     }
+
+
+    /**
+     * list fling到头的时候 展开
+     */
+    @Override
+    public void needExpand() {
+        if(!mControlChange){
+            mValueAnimator.setDuration(500);
+            mValueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
+                @Override
+                public void onAnimationUpdate(ValueAnimator animation) {
+                    mTab.setTranslationY((animation.getAnimatedFraction()-1)*mMaxDistance);
+                }
+            });
+            mValueAnimator.start();
+        }
+    }
 }
diff --git a/app/src/main/java/cq/behaviordemo/listener/IsChildRequestScrollListener.java b/app/src/main/java/cq/behaviordemo/listener/IsChildRequestScrollListener.java
@@ -1,4 +1,4 @@
-package cq.behaviordemo;
+package cq.behaviordemo.listener;
 
 /**
  * Created by cqll on 2016/12/15.
diff --git a/app/src/main/java/cq/behaviordemo/listener/NeedExpandListener.java b/app/src/main/java/cq/behaviordemo/listener/NeedExpandListener.java
@@ -0,0 +1,11 @@
+package cq.behaviordemo.listener;
+
+/**
+ * Created by cqll on 2016/12/15.
+ * list可以滑动的时候,向下滑,然后松开手指,list滑到顶的时候触发
+ * 通知 tab 展开头部
+ */
+
+public interface NeedExpandListener {
+    void needExpand();
+}
diff --git a/app/src/main/java/cq/behaviordemo/listener/SupportNeedExpendListener.java b/app/src/main/java/cq/behaviordemo/listener/SupportNeedExpendListener.java
@@ -0,0 +1,11 @@
+package cq.behaviordemo.listener;
+
+/**
+ * Created by cqll on 2016/12/15.
+ * 是否支持 展开
+ */
+
+public interface SupportNeedExpendListener {
+    void setNeedExpendListener(NeedExpandListener listener);
+    NeedExpandListener getNeedExpendListener();
+}
diff --git a/img/c.gif b/img/c.gif

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-package cq.behaviordemo;`
	`1`	`+package cq.behaviordemo.listener;`
`2`	`2`
`3`	`3`	`/**`
`4`	`4`	`* Created by cqll on 2016/12/15.`