android - Whatsapp 喜欢折叠工具栏

Question

在我的应用程序中，我想实现像可折叠工具栏一样的 Whatsapp 主页。也就是说，在向下滚动列表时，工具栏应该向上移动，选项卡应该固定在顶部。我怎样才能做到这一点？

这是我的应用栏布局

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/appbarLayout"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.design.widget.CollapsingToolbarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/collapsibleToolBarLayout"
        android:fitsSystemWindows="true"
        app:titleEnabled="false"
        app:layout_scrollFlags="scroll|exitUntilCollapsed">                 

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:background="@color/white"
            app:tabTextColor="@color/product_page_btn_grey"
            app:tabSelectedTextColor="@color/upcomer_background_red"
            app:tabIndicatorColor="@color/upcomer_background_red"
            android:layout_gravity="bottom"
            app:layout_scrollFlags="scroll|enterAlways"
            app:tabContentStart="72dp" />

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_collapseMode="parallax"
            app:layout_collapseParallaxMultiplier="0.9"
            android:background="@color/upcomer_background_red"
            app:popupTheme="@style/AppTheme.PopupOverlay" >

            <ImageView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/title_image_view"
                android:contentDescription="@null"
                android:layout_gravity="start|center_vertical"
                android:visibility="gone"
                android:src="@drawable/title"/>
    
            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/title_layout"
                android:visibility="gone">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerVertical="true"
                    android:id="@+id/toolbarText"
                    style="@android:style/TextAppearance.DeviceDefault.Widget.ActionBar.Title"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:id="@+id/send_button"
                    android:layout_marginRight="10dp"
                    android:layout_marginEnd="10dp"
                    android:text="@string/send_text"
                    android:textColor="@color/white"
                    android:textSize="18sp"
                    android:textStyle="bold"
                    android:visibility="gone"
                    android:layout_centerVertical="true"
                    android:layout_alignParentRight="true"
                    android:layout_alignParentEnd="true"/>

            </RelativeLayout>
    
        </android.support.v7.widget.Toolbar>

    </android.support.design.widget.CollapsingToolbarLayout>

</android.support.design.widget.AppBarLayout>

现在 TabLayout 不可见，Toolbar 保留在那里，即使下面的 ViewPager 中的列表已滚动。请帮忙。

Answer 1

要实现此功能，实际上不需要 CollapsingToolbarLayout，您只需折叠设置为 ActionBar 的 Toolbar 即可。

下面的示例代码使用了一个用于将折叠的 ActionBar 的工具栏，以及一个带有 ViewPager 的 TabLayout。

首先确保 MainActivity 使用的样式是没有 ActionBar 的样式，例如:

<style name="AppTheme" parent="@style/Theme.AppCompat.Light.NoActionBar">
    <!-- ....... -->
</style>

MainActivity.java，具有 FragmentPagerAdapter 并设置选项卡:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        // Get the ViewPager and set it's PagerAdapter so that it can display items
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        PagerAdapter pagerAdapter =
                new PagerAdapter(getSupportFragmentManager(), MainActivity.this);
        viewPager.setAdapter(pagerAdapter);

        // Give the TabLayout the ViewPager
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.setupWithViewPager(viewPager);

        // Iterate over all tabs and set the custom view
        for (int i = 0; i < tabLayout.getTabCount(); i++) {
            TabLayout.Tab tab = tabLayout.getTabAt(i);
            tab.setCustomView(pagerAdapter.getTabView(i));
        }

    }


    @Override
    public void onResume() {
        super.onResume();
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    class PagerAdapter extends FragmentPagerAdapter {

        String tabTitles[] = new String[] { "Tab One", "Tab Two", "Tab Three" };
        Context context;

        public PagerAdapter(FragmentManager fm, Context context) {
            super(fm);
            this.context = context;
        }

        @Override
        public int getCount() {
            return tabTitles.length;
        }

        @Override
        public Fragment getItem(int position) {

            switch (position) {
                case 0:
                    return new BlankFragment();
                case 1:
                    return new BlankFragment();
                case 2:
                    return new BlankFragment();
            }

            return null;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            // Generate title based on item position
            return tabTitles[position];
        }

        public View getTabView(int position) {
            View tab = LayoutInflater.from(MainActivity.this).inflate(R.layout.custom_tab, null);
            TextView tv = (TextView) tab.findViewById(R.id.custom_text);
            tv.setText(tabTitles[position]);
            return tab;
        }

    }
}

activity_main.xml

重要部分:

• 使用 CoordinatorLayout
• 在工具栏中使用 app:layout_scrollFlags="scroll|enterAlways|snap"属性
• 使用 app:layout_behavior="@string/appbar_scrolling_view_behavior"ViewPager 属性

这是activity_main.xml文件:

<android.support.design.widget.CoordinatorLayout
    android:id="@+id/main_layout"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">


    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBarLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:elevation="6dp">
    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:background="?attr/colorPrimary"
        android:minHeight="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
        app:elevation="0dp"
        app:layout_scrollFlags="scroll|enterAlways|snap"
        />

    <android.support.design.widget.TabLayout
        android:id="@+id/tab_layout"
        app:tabMode="fixed"
        android:layout_below="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/colorPrimary"
        app:elevation="0dp"
        app:tabTextColor="#d3d3d3"
        app:tabSelectedTextColor="#ffffff"
        app:tabIndicatorColor="#ff00ff"
        android:minHeight="?attr/actionBarSize"
        />

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_below="@+id/tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        />

</android.support.design.widget.CoordinatorLayout>

custom_tab.xml:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/custom_text"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:background="?attr/selectableItemBackground"
        android:gravity="center"
        android:textSize="16dip"
        android:textColor="#ffffff"
        android:singleLine="true"
        />
</LinearLayout>

BlankFragment.java，这只是添加足够的项目使其滚动:

import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;;

public class BlankFragment extends Fragment {

    public BlankFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.fragment_blank, container, false);

        RecyclerView rv = (RecyclerView) rootView.findViewById(R.id.rv_recycler_view);
        rv.setHasFixedSize(true);
        MyAdapter adapter = new MyAdapter(new String[]{"test one", "test two", "test three", "test four", "test five" , "test six" , "test seven", "test eight" , "test nine"});
        rv.setAdapter(adapter);

        LinearLayoutManager llm = new LinearLayoutManager(getActivity());
        rv.setLayoutManager(llm);

        return rootView;
    }

}

fragment_blank.xml，使用 RecyclerView 或任何其他支持嵌套滚动的 View 很重要，例如 NestedScrollView

(旁注:您可以在 api-21 及更高版本上调用 setNestedScrollingEnabled(true) 以使其与 ListView 一起使用):

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.SearchView
        android:id="@+id/sv_search"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Search!"
        android:singleLine="true"
        android:inputType="textNoSuggestions"
        android:layout_gravity="start"
        android:layout_marginRight="18dp"
        android:ems="10" >
    </android.support.v7.widget.SearchView>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_recycler_view"
        android:layout_below="@+id/sv_search"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </android.support.v7.widget.RecyclerView>
</RelativeLayout>

MyAdapter.java，RecyclerView 适配器:

import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    private String[] mDataset;

    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public static class MyViewHolder extends RecyclerView.ViewHolder {
        public CardView mCardView;
        public TextView mTextView;
        public MyViewHolder(View v) {
            super(v);

            mCardView = (CardView) v.findViewById(R.id.card_view);
            mTextView = (TextView) v.findViewById(R.id.tv_text);
        }
    }

    // Provide a suitable constructor (depends on the kind of dataset)
    public MyAdapter(String[] myDataset) {
        mDataset = myDataset;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public MyAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent,
                                                     int viewType) {
        // create a new view
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.card_item, parent, false);
        // set the view's size, margins, paddings and layout parameters
        MyViewHolder vh = new MyViewHolder(v);
        return vh;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.mTextView.setText(mDataset[position]);
    }

    @Override
    public int getItemCount() {
        return mDataset.length;
    }
}

card_item.xml，圆形图片和“blah blah blah”字符串都是静态内容，只有 tv_text TextView 是从数据源更新这个简单的示例:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="68dp" >

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_margin="10dp"
        android:layout_height="62dp"
        card_view:cardCornerRadius="4dp"
        card_view:elevation="14dp">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        <ImageView
            android:id="@+id/iv_image"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:src="@drawable/abc_btn_radio_material">
        </ImageView>

        <TextView
            android:id="@+id/tv_text"

            android:layout_toRightOf ="@+id/iv_image"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center" >
        </TextView>

            <TextView
                android:id="@+id/tv_blah"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="blah blah blah......"
                android:layout_below="@+id/tv_text"
                android:layout_toRightOf="@+id/iv_image"
                android:layout_toEndOf="@+id/iv_image">
            </TextView>

        </RelativeLayout>
    </android.support.v7.widget.CardView>

</RelativeLayout>

build.gradle依赖:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:design:23.0.1'
    compile 'com.android.support:cardview-v7:23.0.1'
    compile 'com.android.support:recyclerview-v7:23.0.1'
}

结果: