Fragment 简介

        Fragment是依赖于Activity的，不能独立存在的。一个Activity里可以有多个Fragment。一个Fragment可以被多个Activity重用。Fragment有自己的生命周期，并能接收输入事件。

一、生命周期

二、创建Fragment

1、静态方法：

２、静态加载的方法

３、Fragment与Activity交互。

 三、示例代码

使用了dataBinding

MainTivity.class

public class MainActivity extends AppCompatActivity {

    private ActivityMainBinding mBinding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);

        //设置页面显示
        MyPageAdapter adapter = new MyPageAdapter(getSupportFragmentManager());
        mBinding.viewPage.setAdapter(adapter);
        mBinding.tabLayout.setupWithViewPager(mBinding.viewPage);
    }
}

layout_main.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <data>

    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <com.google.android.material.tabs.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="40dp"
            app:tabIndicatorColor="@color/white"
            app:tabBackground="@drawable/tab_background"
            app:tabSelectedTextColor="@color/black"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintBottom_toTopOf="@+id/view_page" />

        <androidx.viewpager.widget.ViewPager
            android:id="@+id/view_page"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            app:layout_constraintTop_toBottomOf="@id/tab_layout"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

fagment.class

public class LightFragment extends Fragment {

    private static final String TAG = "LightFragment";

    private FragmentLightBinding mLightBinding;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mLightBinding = FragmentLightBinding.inflate(LayoutInflater.from(requireContext()));
        return mLightBinding.getRoot();
    }
}

fragment_light.xml

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

    <data>

    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".fragment.LightFragment">
        
        <TextView
            android:id="@+id/tv"
            android:text="Hello"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

MyAdapter.class

public class MyPageAdapter extends FragmentPagerAdapter {

    //头部栏标题
    private String[] titles = new String[]{"小灯1", "小灯2", "小灯3", "小灯4"};

    //存放Fragment布局的List
    private static List<Fragment> fragments = new ArrayList<>();

    static {
        //添加页面布局
        fragments.add(new LightFragment(StaticData.ONE));
        fragments.add(new LightFragment(StaticData.TWO));
        fragments.add(new LightFragment(StaticData.THREE));
        fragments.add(new LightFragment(StaticData.FOUR));
    }

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

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

    @Override
    public int getCount() {
        return fragments.size();
    }

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

标签：Fragment,简介,class,LightFragment,new,fragments,public
来源： https://blog.csdn.net/LX_52Hz/article/details/119298731