TabLayout实现底部导航栏

前面的博文写到了TabLayout实现了选项卡的布局，今天练习一个app发现需要一个导航栏在底部的app，在此记录一下，其实就是TabLayout和ViewPager布局顺序换一下就可以了。

效果图先放上来：



接下来开始详细记录：

一、在库中添加依赖
老规矩，先加依赖（依版本添加）

compile 'com.android.support:design:25.2.0'

二、创建主布局

这里上方为ViewPager，下面是TabLayout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
></android.support.v4.view.ViewPager>

<android.support.design.widget.TabLayout
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="@dimen/tab_height"
style="@style/CustomTab"
></android.support.design.widget.TabLayout>

</LinearLayout>

三、写ViewPager的Adapter文件

ViewPagerAdapter.java

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import java.util.List;

public class ViewPagerAdapter extends FragmentStatePagerAdapter {
private Fragment[] mFragments;
public ViewPagerAdapter(FragmentManager fm, Fragment[] fragments) {
super(fm);
mFragments = fragments;
}

@Override
public Fragment getItem(int position) {
return mFragments[position];
}

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

}

四、导航栏布局文件、导航栏选择器文件

布局：tab_layout.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"
>

<ImageView
android:id="@+id/img_tab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>

<TextView
android:id="@+id/tv_tab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="@drawable/tv_tab_selector"
/>

</LinearLayout>

选择器：

导航栏文字选择器：tv_tab_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_selected="true" android:color="@color/black"></item>
<item android:state_selected="false" android:color="@color/darkgray"></item>
</selector>

导航栏图片选择器：tab_mine_selector.xml（这里以其中一个为例，“我” 的选中效果）

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_selected="true" android:drawable="@mipmap/ic_action_mine_selected"></item>
<item android:state_selected="false" android:drawable="@mipmap/ic_action_mine_normal"></item>
</selector>

五、Activity代码：

MainActivity.java

import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.wjy329.bodybuilding.adapter.ViewPagerAdapter;
import com.example.wjy329.bodybuilding.fragment.BuildFragment;
import com.example.wjy329.bodybuilding.fragment.DynamicFragment;
import com.example.wjy329.bodybuilding.fragment.FindFragment;
import com.example.wjy329.bodybuilding.fragment.MineFragment;

public class MainActivity extends AppCompatActivity {
private TabLayout mTabLayout;
//Tab文字
private final int[] TAB_TITLES = new int[]{
R.string.build,R.string.find,R.string.dynamic,R.string.mine
};
//Tab图片
private final int[] TAB_IMGS = new int[]{
R.drawable.tab_build_selector,R.drawable.tab_find_selector,R.drawable.tab_dynamic_selector,R.drawable.tab_mine_selector
};
//Tab数目
private final Fragment[] TAB_FRAGMENTS = new Fragment[]{
new BuildFragment(),new FindFragment(),new DynamicFragment(),new MineFragment()
};
private ViewPagerAdapter mViewPagerAdapter;//适配器
private ViewPager mViewPager;

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

private void initViews() {
mTabLayout = (TabLayout) findViewById(R.id.tablayout);
setTabs(mTabLayout,this.getLayoutInflater(),TAB_TITLES,TAB_IMGS);

mViewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager(),TAB_FRAGMENTS);
mViewPager = (ViewPager) findViewById(R.id.viewpager);
mViewPager.setAdapter(mViewPagerAdapter);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout));//滑动效果
mTabLayout.setOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));//点击效果
}

private void setTabs(TabLayout tabLayout, LayoutInflater inflater, int[] tabTitlees, int[] tabImgs) {
for (int i = 0; i < tabImgs.length; i++) {
TabLayout.Tab tab = tabLayout.newTab();
View view = inflater.inflate(R.layout.tab_custom,null);
tab.setCustomView(view);

TextView tvTitle = (TextView)view.findViewById(R.id.tv_tab);
tvTitle.setText(tabTitlees[i]);
ImageView imgTab = (ImageView) view.findViewById(R.id.img_tab);
imgTab.setImageResource(tabImgs[i]);
tabLayout.addTab(tab);

}
}
}

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