Android 5.0新特性了解（一）----TabLayout

1、在2015年的google大会上，google发布了新的Android Support Material Design库，里面包含了几个新的控件，其中就有一个TabLayout，它就可以完成TabPageIndicator的效果。使用的 android studio进行开发的，所以引用TabLayout很简单，只要在build.gradle中加入compile 'com.android.support:design:23.+'即可。

 效果图：

2、编写xml的时候注意一下这三个属性

app:tabIndicatorColor="#0f0"                每个tab下方的下划线的颜色    
app:tabSelectedTextColor="#00f"             被选中的tab的文本颜色
app:tabTextColor="#f00"                     未被选中的tab的文本颜色

布局文件activity_main.xml

<?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.design.widget.TabLayout
        android:id="@+id/tablayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#777"
        app:tabIndicatorColor="#0f0"
        app:tabSelectedTextColor="#00f"
        app:tabTextColor="#f00"
        />


    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#cccc"
        />

</LinearLayout>

3、创建MyFragmentOne.java文件　　

package com.wangjitao.myapptest.fragment;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.wangjitao.myapptest.R;

/**
 * Created by wangjitao on 2016/3/7.
 */
public class MyFragmentOne extends Fragment {

    public MyFragmentOne(){

    };

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        return inflater.inflate(R.layout.fragment_one, container, false);
    }
}

　　

4、创建ViewPager的适配器MyAdapter.java 

package com.wangjitao.myapptest.adapter;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;

import java.util.List;

/**
 * Created by jh on 2016/3/7.
 */
public class MyAdapter extends FragmentStatePagerAdapter {
    private List<Fragment> list_Fragments ;
    private List<String> list_Titles ;
    public MyAdapter(FragmentManager fm ,List<Fragment> list_Fragments  ,List<String> list_Titles ) {
        super(fm);
        this.list_Fragments = list_Fragments ;
        this.list_Titles = list_Titles ;
    }

    @Override
    public Fragment getItem(int position) {
        return list_Fragments.get(position);
    }

    @Override
    public int getCount() {
        int rec = 0 ;
        if (list_Fragments != null && list_Fragments.size() > 0){
            rec = list_Fragments.size();
        }
        return rec;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return list_Titles.get(position);
    }
}

　　5、MainActivity.java

package com.wangjitao.myapptest.activity;


import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.os.Bundle;

import com.wangjitao.myapptest.R;
import com.wangjitao.myapptest.adapter.MyAdapter;
import com.wangjitao.myapptest.fragment.MyFragmentOne;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends FragmentActivity {
    public static final String TAG = "MainActivity";
    private TabLayout mTabLayout ;
    private ViewPager mViewPager ;

    private List<Fragment> list_Fragments ;
    private List<String> list_Titles ;

    private MyAdapter mMyAdapter ;

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

    private void initData() {
        list_Fragments = new ArrayList<>();
        list_Titles = new ArrayList<>();
      for(int i = 0 ; i < 4 ; i++){
          list_Fragments.add(new MyFragmentOne());
      }
        list_Titles.add("one");
        list_Titles.add("two");
        list_Titles.add("three");
        list_Titles.add("four");

        mMyAdapter = new MyAdapter(getSupportFragmentManager(),list_Fragments,list_Titles);
        mViewPager.setAdapter(mMyAdapter);
        mTabLayout.setupWithViewPager(mViewPager);
    }

    private void initView() {
        mTabLayout = (TabLayout)findViewById(R.id.tablayout);
        mViewPager = (ViewPager)findViewById(R.id.viewpager);
    }
}

　　补充：TabLayout中的Tab似乎没有占满屏幕的宽度，怎么解决呢？

　　代码：

tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
tabLayout.setTabMode(TabLayout.MODE_FIXED);

　　布局文件设置：

<android.support.design.widget.TabLayout
        android:id="@+id/tabLayout"
        app:tabGravity="fill"
        app:tabMode="fixed"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />