android design library提供的TabLayout的用法

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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：

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

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~

定义TabLayout的样式

默认的情况下，TabLayout的tab indicator的颜色是Material Design中的accent color(#009688)，我们可以稍作修改：

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">    <item name="tabIndicatorColor">#0000FF</item></style>

在布局中使用：

<android.support.design.widget.TabLayout       android:id="@+id/sliding_tabs"       style="@style/MyCustomTabLayout"       android:layout_width="match_parent"       android:layout_height="wrap_content"        />

还有一些其他的样式可供选择：

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">    <item name="tabMaxWidth">@dimen/tab_max_width</item>    <item name="tabIndicatorColor">?attr/colorAccent</item>    <item name="tabIndicatorHeight">2dp</item>    <item name="tabPaddingStart">12dp</item>    <item name="tabPaddingEnd">12dp</item>    <item name="tabBackground">?attr/selectableItemBackground</item>    <item name="tabTextAppearance">@style/MyCustomTabTextAppearance</item>    <item name="tabSelectedTextColor">?android:textColorPrimary</item></style><style name="MyCustomTabTextAppearance" parent="TextAppearance.Design.Tab">    <item name="android:textSize">14sp</item>    <item name="android:textColor">?android:textColorSecondary</item>    <item name="textAllCaps">true</item></style>

添加icon到tab

当前的TabLayout没有方法让我们去添加icon，我们可以使用SpannableString结合ImageSpan来实现，在SimpleFragmentPagerAdapter中：

private int[] imageResId = {        R.drawable.ic_one,        R.drawable.ic_two,        R.drawable.ic_three};// ...@Overridepublic CharSequence getPageTitle(int position) {    // Generate title based on item position    // return tabTitles[position];    Drawable image = context.getResources().getDrawable(imageResId[position]);    image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());    SpannableString sb = new SpannableString(" ");    ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);    sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);    return sb;}

运行，发现没有显示，这是因为TabLayout创建的tab默认设置textAllCaps属性为true，这阻止了ImageSpan被渲染出来，可以通过下面的样式文件定义来改变：

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">      <item name="tabTextAppearance">@style/MyCustomTextAppearance</item></style><style name="MyCustomTextAppearance" parent="TextAppearance.Design.Tab">      <item name="textAllCaps">false</item></style>

现在运行，效果就出来了。

添加icon和text到tab

@Overridepublic CharSequence getPageTitle(int position) {    // Generate title based on item position    Drawable image = context.getResources().getDrawable(imageResId[position]);    image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());        // Replace blank spaces with image icon    SpannableString sb = new SpannableString("   " + tabTitles[position]);    ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);    sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);    return sb;}

我们看到在实例化SpannableString的时候，我在tabTitles[position]前面加了几个空格，这些空格的位置是用来放置icon的。

添加自定义的view到tab

适配器中增加getTabView(...)方法：

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 android.view.LayoutInflater;import android.view.View;import android.widget.ImageView;import android.widget.TextView;import me.chenfuduo.myfragmentdemo.R;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 int[] imageResId = {R.drawable.avatar_enterprise_vip,            R.drawable.avatar_grassroot,            R.drawable.avatar_vip};    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) {        //第一次的代码        //return tabTitles[position];        //第二次的代码       /**         Drawable image = context.getResources().getDrawable(imageResId[position]);        image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());        SpannableString sb = new SpannableString(" " + tabTitles[position]);        ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);        sb.setSpan(imageSpan, 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);        return sb;*/        return null;    }    public View getTabView(int position){        View view = LayoutInflater.from(context).inflate(R.layout.tab_item, null);        TextView tv= (TextView) view.findViewById(R.id.textView);        tv.setText(tabTitles[position]);        ImageView img = (ImageView) view.findViewById(R.id.imageView);        img.setImageResource(imageResId[position]);        return view;    }}

简单的布局：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    >    <ImageView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/imageView"        android:layout_centerVertical="true"        />    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_toRightOf="@id/imageView"        android:layout_centerVertical="true"        android:id="@+id/textView"        android:layout_marginLeft="3dp"        /></RelativeLayout>

使用：

@Overrideprotected 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);       for (int i = 0; i < tabLayout.getTabCount(); i++) {           TabLayout.Tab tab = tabLayout.getTabAt(i);           tab.setCustomView(pagerAdapter.getTabView(i));       }   }

处理配置改变

当屏幕旋转或者配置改变的时候，我们需要保存当前的状态。

@Override   public void onSaveInstanceState(Bundle outState) {       super.onSaveInstanceState(outState);       outState.putInt(POSITION,tabLayout.getSelectedTabPosition());   }   @Override   protected void onRestoreInstanceState(Bundle savedInstanceState) {       super.onRestoreInstanceState(savedInstanceState);       viewPager.setCurrentItem(savedInstanceState.getInt(POSITION));   }

需要注意的是getSelectedTabPosition()方法是最新的design support library才有的。
最后的效果如下：

源码下载

http://download.csdn.net/detail/huningjun/9833115

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