Android中TabLayout+ViewPager 简单实现app底部Tab导航栏

前言

在谷歌发布Android Design Support Library之前，app底部tab布局的实现方法就有很多种，其中有RadioGroup+FrameLayout、TabHost+Fragment、FragmentPagerAdapter+ViewPager等方法，虽然这些方法虽然能达到同样的效果，但我个人总觉得有些繁琐。然而，Google在2015的IO大会上，给开发者们带来了全新的Android Design Support Library，里面包含了许多新控件，这些新控件有许多是把以前的一些第三方开源库官方化，实现起来更为简便，简直是开发者的福音。其中的TabLayout控件让我想到了app底部的tab布局，而且TabLayout用法更加简单，为何不试试用TabLayout实现简单的实现呢？好了，话不多说，先看看效果：

是不是和以前的方法实现的效果一样呢？下面我们来看看怎么简单实现。

过程

因为TabLayout和ViewPager分别是属于design和v4包下的，所以我们先在app的build.gradle中添加：

compile 'com.android.support:design:23.1.1' compile 'com.android.support:support-v4:23.1.1'

然后在主布局文件activity_main.xml中添加布局控件：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <android.support.v4.view.ViewPager android:id="@+id/viewPager" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:scrollbars="none"> </android.support.v4.view.ViewPager> <android.support.design.widget.TabLayout android:id="@+id/tabLayout" android:layout_width="match_parent" android:layout_height="50dp" app:tabGravity="fill" app:tabIndicatorHeight="0dp" app:tabMode="fixed" app:tabSelectedTextColor="#FF4081" app:tabTextColor="#000"> </android.support.design.widget.TabLayout> </LinearLayout>

就仅一个ViewPager和TabLayout就可以实现，是不是比以前的方法繁琐的布局简便很多？上面TabLayout中app:tabIndicatorHeight="0dp"是为了不显示tab底部的横线，app:tabMode="fixed"是让底部tab布局不可滑动。

接下来就和往常一样在MainActivity.java中初始化布局，设置适配器：

private void initViews() { mTablayout= (TabLayout) findViewById(R.id.tabLayout); mViewPager= (ViewPager) findViewById(R.id.viewPager); mViewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) { private String[] mTitles = new String[]{"唐僧", "大师兄", "二师兄","沙师弟"}; @Override public Fragment getItem(int position) { if (position == 1) { return new TwoFragment(); } else if (position == 2) { return new ThreeFragment(); }else if (position==3){ return new FourFragment(); } return new OneFragment(); } @Override public int getCount() { return mTitles.length; } @Override public CharSequence getPageTitle(int position) { return mTitles[position]; } }); mTablayout.setupWithViewPager(mViewPager); one = mTablayout.getTabAt(0); two = mTablayout.getTabAt(1); three = mTablayout.getTabAt(2); four = mTablayout.getTabAt(3); one.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); two.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); three.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); four.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); }

上面要注意的地方是别忘了在FragmentPagerAdapter中手动添加：

@Override public CharSequence getPageTitle(int position) { return mTitles[position]; }

不然不显示底部的文字。

mTablayout.setupWithViewPager(mViewPager);将TabLayout和ViewPager关联起来。

one = mTablayout.getTabAt(0);获取底部单个tab，用来添加初始化图片，注意下标都是从0开始的。

初始化监听事件

private void initEvents() { mTablayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() { @Override public void onTabSelected(TabLayout.Tab tab) { if (tab == mTablayout.getTabAt(0)) { one.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(0); } else if (tab == mTablayout.getTabAt(1)) { two.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(1); } else if (tab == mTablayout.getTabAt(2)) { three.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(2); }else if (tab == mTablayout.getTabAt(3)){ four.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(3); } } @Override public void onTabUnselected(TabLayout.Tab tab) { if (tab == mTablayout.getTabAt(0)) { one.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } else if (tab == mTablayout.getTabAt(1)) { two.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } else if (tab == mTablayout.getTabAt(2)) { three.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); }else if (tab == mTablayout.getTabAt(3)){ four.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } } @Override public void onTabReselected(TabLayout.Tab tab) { } }); }

在onTabSelected中设置选中tab时切换的图片，onTabUnselected中设置没有被选中时的图片。别忘了mViewPager.setCurrentItem(0);这句，这是用来点击tab时切换ViewPager，如果不加这一句的话滑动ViewPager底部tab可以切换，但是点击tab而ViewPager不会切换。

Fragment中的简单布局

fragment_one.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="唐僧" android:layout_marginTop="100dp" android:layout_gravity="center" android:textSize="30sp"/> </LinearLayout>

OneFragment.java

public class OneFragment extends Fragment{ @Nullable @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_one,container,false); } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); } }

MainActivity.java完整代码：

public class MainActivity extends AppCompatActivity { private TabLayout mTablayout; private ViewPager mViewPager; private TabLayout.Tab one; private TabLayout.Tab two; private TabLayout.Tab three; private TabLayout.Tab four; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initViews(); initEvents(); } private void initEvents() { mTablayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() { @Override public void onTabSelected(TabLayout.Tab tab) { if (tab == mTablayout.getTabAt(0)) { one.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(0); } else if (tab == mTablayout.getTabAt(1)) { two.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(1); } else if (tab == mTablayout.getTabAt(2)) { three.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(2); }else if (tab == mTablayout.getTabAt(3)){ four.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); mViewPager.setCurrentItem(3); } } @Override public void onTabUnselected(TabLayout.Tab tab) { if (tab == mTablayout.getTabAt(0)) { one.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } else if (tab == mTablayout.getTabAt(1)) { two.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } else if (tab == mTablayout.getTabAt(2)) { three.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); }else if (tab == mTablayout.getTabAt(3)){ four.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } } @Override public void onTabReselected(TabLayout.Tab tab) { } }); } private void initViews() { mTablayout= (TabLayout) findViewById(R.id.tabLayout); mViewPager= (ViewPager) findViewById(R.id.viewPager); mViewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) { private String[] mTitles = new String[]{"唐僧", "大师兄", "二师兄","沙师弟"}; @Override public Fragment getItem(int position) { if (position == 1) { return new TwoFragment(); } else if (position == 2) { return new ThreeFragment(); }else if (position==3){ return new FourFragment(); } return new OneFragment(); } @Override public int getCount() { return mTitles.length; } @Override public CharSequence getPageTitle(int position) { return mTitles[position]; } }); mTablayout.setupWithViewPager(mViewPager); one = mTablayout.getTabAt(0); two = mTablayout.getTabAt(1); three = mTablayout.getTabAt(2); four = mTablayout.getTabAt(3); one.setIcon(getResources().getDrawable(R.drawable.ic_favorite_black_18dp)); two.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); three.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); four.setIcon(getResources().getDrawable(R.mipmap.ic_launcher)); } }

结束语

以上就是简单用TabLayout+ViewPager实现app底部Tab布局的整个过程，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。