Android 使用TabLayout制作下划线能滑动的Tab标签页-design

google提供的Design开发包里，有很多实用好看的新控件，这里介绍下使用TabLayout+ViewPager实现下划线能滑动的Tab标签页

效果图



不使用google的design包，我们也可以自己制作这样的效果，详看我的这篇博客：http://blog.csdn.net/zhuwentao2150/article/details/51407661

要使用Design包，在项目的build.gradle中添加下依赖就好（记得更新SDK到最新版本）

dependencies {
compile 'com.android.support:design:23.4.0'
}

先来看布局

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

<android.support.design.widget.TabLayout
android:id="@+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/colorPrimary"
app:tabSelectedTextColor="#ffffff"
app:tabIndicatorColor="#ff00ff"
app:tabTextColor="#000000"
app:tabIndicatorHeight="5dp"
app:tabMode="fixed"/>

<android.support.v4.view.ViewPager
android:id="@+id/vp_tab_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

</LinearLayout>

常用属性

tabSelectedTextColor：当Tab标签被选中时的文字颜色

tabTextColor：Tab标签中文字的默认颜色

tabIndicatorColor：下划线颜色

tabIndicatorHeight：下划线的高度

tabBackground：设置Tab标签的背景

tabMode：Tab标签的行为模式

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. They are best used for browsing contexts in touch interfaces when users don’t need to directly compare the tab labels. This mode is commonly used with a ViewPager.

两种模式的差异：

tabMode=”scrollable”

滚动模式，TabLayout可以滚动

标签多时，TabLayout支持滑动查看



标签少时，，这些Tab会挤在一侧，且各个Tab不是等量分布的，有的占地多有的占地少



tabMode=”fixed”

填充模式，TabLayout不可滚动，所有的Tab都被限制在一定区域内

标签多时，Tab会受到挤压



Tab少时，各个Tab等量空间分布



Fragment页面

/**
* ViewPager页面
* Created by zhuwentao on 2016-08-22.
*/
public class ViewPagerFragment extends Fragment{

private String mPageNo;

private TextView mPageNoTv;

/** 状态类型常量 */
public static final String STATUS_TYPE = "pagerType";

public static final String STATUS_ONE = "One";

public static final String STATUS_TWO = "Two";

public static final String STATUS_THREE = "Three";

/**
* 取得Fragment实例
*/
public static ViewPagerFragment newInstance(Bundle args) {
ViewPagerFragment fragment = new ViewPagerFragment();
fragment.setArguments(args);
return fragment;
}

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mPageNo = getArguments().getString(STATUS_TYPE);
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_tab, container, false);
mPageNoTv = (TextView) v.findViewById(R.id.tv_page_text);
mPageNoTv.setText(mPageNo);
return v;
}

}

Activity界面

public class TabLayoutActivity extends AppCompatActivity {

private ViewPager mPageVp;

private TabLayout mLayoutTab;

/**
* 选项卡总数
*/
private static final int TAB_COUNT = 3;

private static final int TAB_0 = 0;

private static final int TAB_1 = 1;

private static final int TAB_2 = 2;

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

/**
* 初始化UI
*/
private void initUI() {
mPageVp = (ViewPager) findViewById(R.id.vp_tab_pager);
mLayoutTab = (TabLayout) findViewById(R.id.tab_layout);

mPageVp.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
// 把TabLayout和ViewPager关联起来
mLayoutTab.setupWithViewPager(mPageVp);
}

/**
* ViewPager适配器
*/
public class MyPagerAdapter extends FragmentPagerAdapter {

// 定义Tab标题
private String[] tabTitles = new String[]{
"One","Two","Three"
};

public MyPagerAdapter(FragmentManager fm) {
super(fm);
}

@Override
public Fragment getItem(int position) {
Bundle args = new Bundle();
boolean flag = true;
switch (position) {
case TAB_0:
args.putString(ViewPagerFragment.STATUS_TYPE, ViewPagerFragment.STATUS_ONE);
break;
case TAB_1:
args.putString(ViewPagerFragment.STATUS_TYPE, ViewPagerFragment.STATUS_TWO);
break;
case TAB_2:
args.putString(ViewPagerFragment.STATUS_TYPE, ViewPagerFragment.STATUS_THREE);
break;
default:
flag = false;
break;
}
if (flag) {
// 返回对应的Fragment页面
return ViewPagerFragment.newInstance(args);
}
return null;
}

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

@Override
public CharSequence getPageTitle(int position) {
// 设置Page对应的Tab标题
return tabTitles[position];
}
}

}

调用setupWithViewPager()方法传入一个ViewPager对象，请确保该ViewPager对象已经通过setAdapter设置好了Adapter适配器

从源码可以看出

public void setupWithViewPager(@Nullable final ViewPager viewPager) {
if (mViewPager != null && mPageChangeListener != null) {
// If we've already been setup with a ViewPager, remove us from it
mViewPager .removeOnPageChangeListener( mPageChangeListener);
}

if (viewPager != null ) {
final PagerAdapter adapter = viewPager.getAdapter();
if (adapter == null) {
throw new IllegalArgumentException( "ViewPager does not have a PagerAdapter set");
}
// ......

如果ViewPager的Adapter为空，则会抛出IllegalArgumentException异常

把 TabLayout和 ViewPager 关联起来，该方法相当于帮我们封装好了 addOnPageChangeListener 和setOnTabSelectedListener ，帮我们节省了大量的代码。