上一篇部落格已經詳細介紹了底部導航欄的實作,這篇是在上一篇的基礎上加上頂部導航,不懂的可以看我的上一篇部落格。位址如下:
Android底部導航實作的簡便方法RadioGroup+Fragment
因為很多app都是底部導航和頂部導航嵌套使用,是以現在我講的也是在上一篇部落格的代碼基礎下,在底部導航的Fragment中使用頂部導航,相信如果你學會了怎麼在Fragment使用頂部導航,在Activity中使用的話對你來說應該是小兒科,回歸正題。
頂部導航欄TabLayout+ViewPager
1.修改上一篇的首頁布局檔案即fragment_home.xml,裡面主要由TabLayout和ViewPager組成。Tablayout布局頂部導航,ViewPager布局各導航的内容。同時建立一個frament_tab的布局,裡面就一個TextView,便于分辨出各導航,可根據所需功能自行修改。
fragment_home.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">
<android.support.design.widget.TabLayout
android:id="@+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="40dp">
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="@+id/page"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
</LinearLayout>
frament_tab
<?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">
<TextView
android:id="@+id/tv_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="關注"
android:textSize="20sp"
android:gravity="center"/>
</LinearLayout>
2.建立一個fragment類,TabFragment,注意繼承時繼承android.support.v4.app.Fragment,這個fragment的作用就是各導航的内容
public class TabFragment extends Fragment {
private TextView titleTv;
private String mTitle;
//這個構造方法是便于各導航同時調用一個fragment
public TabFragment(String title){
mTitle=title;
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState){
View view=inflater.inflate(R.layout.fragment_tab,container,false);
titleTv=view.findViewById(R.id.tv_title);
titleTv.setText(mTitle);
return view;
}
}
3.建立ViewPager的設配器,繼承FragmentPagerAdapter
public class FragmentAdapter extends FragmentPagerAdapter {
private List<TabFragment> mFragmentList;//各導航的Fragment
private List<String> mTitle; //導航的标題
public FragmentAdapter(FragmentManager fragmentManager,List<TabFragment>fragments,List<String>title){
super(fragmentManager);
mFragmentList=fragments;
mTitle=title;
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
@Override
public CharSequence getPageTitle(int position) {
return mTitle.get(position);
}
}
4.最後隻需要在HomeFragment布局渲染即可。
public class HomeFragment extends Fragment{
private ViewPager pager;
private FragmentAdapter fragmentAdapter;
private List<TabFragment> fragmentList;
private TabLayout tabLayout;
private TabFragment fragment1,fragment2,fragment3,fragment4,fragment5;
private List<String> mTitles;
private String [] title={"關注","推薦","廣州","視訊","熱點"};
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState){
View view=inflater.inflate(R.layout.fragment_home,container,false);
pager=view.findViewById(R.id.page);
tabLayout=view.findViewById(R.id.tab_layout);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
fragmentList=new ArrayList<>();
mTitles=new ArrayList<>();
for(int i=0;i<title.length;i++){
mTitles.add(title[i]);
fragmentList.add(new TabFragment(title[i]));
}
fragmentAdapter=new FragmentAdapter(getActivity().getSupportFragmentManager(),fragmentList,mTitles);
pager.setAdapter(fragmentAdapter);
tabLayout.setupWithViewPager(pager);//與ViewPage建立關系
}
}