android design library提供的TabLayout的用法

在开发中，我们常常需要ViewPager结合Fragment一起使用，如下图：

我们可以使用三方开源的PagerSlidingTabStrip去实现，或者viewpagerindicator，我一般都偏向前者。现在我们可以使用Design support library库的TabLayout去实现了。最终的效果图：

效果图

创建布局

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


    <!--app:tabMode="scrollable"  这个属性我在代码中设置了-->
   <!-- tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);-->
    <android.support.design.widget.TabLayout
        android:id="@+id/sliding_tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
         />

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0px"
        android:layout_weight="1"
        android:background="@android:color/white" />

</LinearLayout>

在xml添加TabLayout，如同ViewPager，直接`android.support.design.widget.TabLayout`即可。还有其他的属性我会在代码中设置。

创建Fragment

package me.chenfuduo.myfragmentdemo.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 android.widget.TextView;

import me.chenfuduo.myfragmentdemo.R;

/**
 * Created by Administrator on 2015/7/30.
 */
public class PageFragment extends Fragment {

    public static final String ARG_PAGE = "ARG_PAGE";
    private int mPage;

    public static PageFragment newInstance(int page) {
        Bundle args = new Bundle();
        args.putInt(ARG_PAGE, page);
        PageFragment pageFragment = new PageFragment();
        pageFragment.setArguments(args);
        return pageFragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPage = getArguments().getInt(ARG_PAGE);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_page, container, false);
        TextView textView = (TextView) view;
        textView.setText("Fragment #" + mPage);
        return view;
    }

}

其中Fragment的布局为：

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

ViewPager的适配器

package me.chenfuduo.myfragmentdemo.adapter;

import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import me.chenfuduo.myfragmentdemo.fragment.PageFragment;

/**
 * Created by Administrator on 2015/7/30.
 */
public class SimpleFragmentPagerAdapter extends FragmentPagerAdapter {

    final int PAGE_COUNT = 3;
    private String tabTitles[] = new String[]{"tab1","tab2","tab3"};
    private Context context;

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

    @Override
    public Fragment getItem(int position) {
        return PageFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        return PAGE_COUNT;
    }

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

设置TabLayout

package me.chenfuduo.myfragmentdemo;

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

import me.chenfuduo.myfragmentdemo.adapter.SimpleFragmentPagerAdapter;

public class ThirdActivity extends FragmentActivity {

    private SimpleFragmentPagerAdapter pagerAdapter;

    private ViewPager viewPager;

    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_third);
        pagerAdapter = new SimpleFragmentPagerAdapter(getSupportFragmentManager(), this);
        viewPager = (ViewPager) findViewById(R.id.viewpager);
        viewPager.setAdapter(pagerAdapter);
        tabLayout = (TabLayout) findViewById(R.id.sliding_tabs);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setTabMode(TabLayout.MODE_FIXED);
    }
}

这里提几点我遇到的问题

tabLayout.setTabMode(TabLayout.MODE_FIXED);

开始我设置的是：

tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
运行后，三个TabLayout标签挤到一块去了。如下：

查看api，找到结果了。这个tabmode有两个属性值：

MODE_FIXED:Fixed tabs display all tabs concurrently and are best used with content that benefits from quick pivots between tabs.
MODE_SCROLLABLE:Scrollable tabs display a subset of tabs at any given moment, and can contain longer tab labels and a larger number of tabs.

不做过多的解释，MODE_SCROLLABLE适合很多tabs的情况。

setupWithViewPager必须在ViewPager.setAdapter()之后调用

setupWithViewPager必须在ViewPager.setAdapter()之后调用

查看下源码就知道了：

public void setupWithViewPager(ViewPager viewPager) {
    PagerAdapter adapter = viewPager.getAdapter();
    if(adapter == null) {
        throw new IllegalArgumentException("ViewPager does not have a PagerAdapter set");
    } else {
        ...
    }
}

以上就是最基本的用法，是不是很简单。哈~

http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2015/0731/3247.html