recyclervire 滑到顶部的时候下滑 tab才会向下移动

Author: csnowstack

.idea/misc.xml

@@ -22,6 +22,9 @@
 > 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.....
+
 ### 实现
 
 #### 依赖关系

.idea/vcs.xml

@@ -0,0 +1,10 @@
+package cq.behaviordemo;
+
+/**
+ * Created by cqll on 2016/12/15.
+ * 判断子view是否需要滑动
+ */
+
+public interface IsChildRequestScrollListener {
+    boolean requestScroll();
+}

README.md

@@ -9,11 +9,13 @@
 import android.view.View;
 import android.view.ViewGroup;
 
+import cq.behaviordemo.adapter.FriendInfoAdapter;
+
 /**
  * Created by cqll on 2016/9/30.
  */
 
-public class ItemFragment extends Fragment {
+public class ItemFragment extends Fragment implements IsChildRequestScrollListener{
 
     private RecyclerView mRecyclerView;
 
@@ -40,4 +42,11 @@ private void initView() {
     }
 
 
+    @Override
+    public boolean requestScroll() {
+        //不是在顶部
+        return !(mRecyclerView.getAdapter()!=null&&
+                mRecyclerView.getAdapter().getItemCount()>0&&
+                ((LinearLayoutManager)mRecyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition()==0);
+    }
 }

app/src/main/java/cq/behaviordemo/IsChildRequestScrollListener.java

@@ -2,12 +2,11 @@
 
 import android.os.Bundle;
 import android.support.design.widget.TabLayout;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentStatePagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.support.v7.app.AppCompatActivity;
 
+import cq.behaviordemo.adapter.ItemAdapter;
+
 public class MainActivity extends AppCompatActivity {
     private TabLayout mTabLayout;
     private ViewPager mViewPager;
@@ -28,7 +27,7 @@ private void findView() {
 
     private void initView() {
 
-        mViewPager.setAdapter(new ItemAdapter(getSupportFragmentManager()));
+        mViewPager.setAdapter(new ItemAdapter(getSupportFragmentManager(),mViewPager));
         mTabLayout.setupWithViewPager(mViewPager);
     }
 
@@ -49,32 +48,11 @@ public void onTabReselected(TabLayout.Tab tab) {
 
             }
         });
-    }
-
-
 
-    static class ItemAdapter extends FragmentStatePagerAdapter{
-        private String [] titles={"MEDIA","ABOUT","REVIEWS"};
-
-        public ItemAdapter(FragmentManager fm) {
-            super(fm);
-        }
+    }
 
-        @Override
-        public Fragment getItem(int position) {
-            return ItemFragment.newInstance();
-        }
 
-        @Override
-        public int getCount() {
-            return titles.length;
-        }
 
-        @Override
-        public CharSequence getPageTitle(int position) {
-            return titles[position];
-        }
-    }
 
 
 }

app/src/main/java/cq/behaviordemo/ItemFragment.java

@@ -1,11 +1,13 @@
-package cq.behaviordemo;
+package cq.behaviordemo.adapter;
 
 import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
 
+import cq.behaviordemo.R;
+
 /**
  * Created by cqll on 2016/9/30.
  */

app/src/main/java/cq/behaviordemo/MainActivity.java

@@ -0,0 +1,64 @@
+package cq.behaviordemo.adapter;
+
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.app.FragmentStatePagerAdapter;
+import android.support.v4.view.ViewPager;
+
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.List;
+
+import cq.behaviordemo.IsChildRequestScrollListener;
+import cq.behaviordemo.ItemFragment;
+
+/**
+ * Created by cqll on 2016/12/15.
+ */
+
+public  class ItemAdapter extends FragmentStatePagerAdapter implements IsChildRequestScrollListener{
+    private String [] titles={"MEDIA","ABOUT","REVIEWS"};
+    private WeakReference<ViewPager> mViewPager;//也许有点用
+    private List<ItemFragment> mFragments;
+    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());
+    }
+
+    @Override
+    public Fragment getItem(int position) {
+        return mFragments.get(position);
+    }
+
+    @Override
+    public int getCount() {
+        return titles.length;
+    }
+
+    @Override
+    public CharSequence getPageTitle(int position) {
+        return titles[position];
+    }
+
+
+    @Override
+    public boolean requestScroll() {
+        //有子项目,有设置 vp ,没被清掉
+        if(mViewPager!=null&&mViewPager.get()!=null ){
+            int currentItem=mViewPager.get().getCurrentItem();
+            //实现了接口
+            if(getItem(currentItem) instanceof IsChildRequestScrollListener)
+                return ((IsChildRequestScrollListener)getItem(currentItem)).requestScroll();
+        }
+
+        return false;
+    }
+}

app/src/main/java/cq/behaviordemo/FriendInfoAdapter.java renamed to app/src/main/java/cq/behaviordemo/adapter/FriendInfoAdapter.java

@@ -1,4 +1,4 @@
-package cq.behaviordemo;
+package cq.behaviordemo.behavior;
 
 import android.content.Context;
 import android.support.design.widget.CoordinatorLayout;
@@ -7,6 +7,9 @@
 import android.util.DisplayMetrics;
 import android.view.View;
 
+import cq.behaviordemo.Constants;
+import cq.behaviordemo.R;
+
 /**
  * Created by cqll on 2016/12/12.
  */
@@ -24,7 +27,7 @@ public BGBehavior(Context context, AttributeSet attrs) {
         DisplayMetrics metrics=context.getResources().getDisplayMetrics();
         mWidth=metrics.widthPixels;
 
-        mStartTop=(int) (mHeightToolbar+mIconSizeStart/2+mWidth*Constants.FRACTION_WIDTH_BGCONTENT*Constants.FRACTION_HEIGHT_BGCONTENT/2f);
+        mStartTop=(int) (mHeightToolbar+mIconSizeStart/2+mWidth* Constants.FRACTION_WIDTH_BGCONTENT*Constants.FRACTION_HEIGHT_BGCONTENT/2f);
     }
 
 

app/src/main/java/cq/behaviordemo/adapter/ItemAdapter.java

@@ -1,4 +1,4 @@
-package cq.behaviordemo;
+package cq.behaviordemo.behavior;
 
 import android.content.Context;
 import android.support.design.widget.CoordinatorLayout;
@@ -7,6 +7,9 @@
 import android.util.DisplayMetrics;
 import android.view.View;
 
+import cq.behaviordemo.Constants;
+import cq.behaviordemo.R;
+
 /**
  * Created by cqll on 2016/12/12.
  */
@@ -25,7 +28,7 @@ public BGContentBehavior(Context context, AttributeSet attrs) {
 
         DisplayMetrics metrics=context.getResources().getDisplayMetrics();
         mWidth=metrics.widthPixels;
-        mBgWidthStart= (int) (mWidth*Constants.FRACTION_WIDTH_BGCONTENT);
+        mBgWidthStart= (int) (mWidth* Constants.FRACTION_WIDTH_BGCONTENT);
         mBgHeightStart= (int) (mBgWidthStart*Constants.FRACTION_HEIGHT_BGCONTENT);
 
     }