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Fragment 一

作者：互联网

今天学习了Fragment 的创建：静态和动态.代码比较简单，加有注释，不再详解。

Fragment是Android3.0后引入的一个新的API，他出现的初衷是为了适应大屏幕的平板电脑， 当然现在他仍然是平板APP UI设计的宠儿，而且我们普通手机开发也会加入这个Fragment， 我们可以把他看成一个小型的Activity，又称Activity片段！想想，如果一个很大的界面，我们 就一个布局，写起界面来会有多麻烦，而且如果组件多的话是管理起来也很麻烦！而使用Fragment 我们可以把屏幕划分成几块，然后进行分组，进行一个模块化的管理！从而可以更加方便的在 运行过程中动态地更新Activity的用户界面！另外Fragment并不能单独使用，他需要嵌套在Activity 中使用，尽管他拥有自己的生命周期，但是还是会受到宿主Activity的生命周期的影响，比如Activity 被destory销毁了，他也会跟着销毁！

首先是文件

 

 

 

MainActivit

package com.example.fragment;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    //静态
    public void staticFragment(View view) {
        Intent intent = new Intent(MainActivity.this, StaticFragmentActivity.class);
        startActivity(intent);
    }
    //动态
    public void DynameicFragment(View view) {
        Intent intent = new Intent(MainActivity.this, DynameicFragmentActivity.class);
        startActivity(intent);
    }
}

 

StacticFragementActivity

package com.example.fragment;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

public class StaticFragmentActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_staticfragment);
    }
}
package com.example.fragment;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import com.example.fragment.fragment.DynameicFragment;

public class DynameicFragmentActivity extends AppCompatActivity {

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


        if (savedInstanceState == null) {
            //得到FragmentManager
            FragmentManager fragmentManager = getSupportFragmentManager();
            //得到FragmentTransaction 一次事务打包的操作
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

            fragmentTransaction.add(R.id.dynameicfragment, DynameicFragment.class, null)
                    .setReorderingAllowed(true)
                    //.addToBackStack(null)  //压缩到栈里
                    .commit()
            ;

        }

    }




}


DynameicFragment



package com.example.fragment.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

import com.example.fragment.R;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link DynameicFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class DynameicFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public DynameicFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment DynameicFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static DynameicFragment newInstance(String param1, String param2) {
        DynameicFragment fragment = new DynameicFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_dynameic, container, false);
    }
}



StaticFragment



package com.example.fragment.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

import com.example.fragment.R;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link StaticFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class StaticFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public StaticFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment StaticFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static StaticFragment newInstance(String param1, String param2) {
        StaticFragment fragment = new StaticFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_static, container, false);
    }
}



activity_dynameicfragment.xml



<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".DynameicFragmentActivity">


<androidx.fragment.app.FragmentContainerView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/dynameicfragment"

    >



</androidx.fragment.app.FragmentContainerView>

</LinearLayout>



activity_main_xml



<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical"
    >

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAlignment="center"
    android:text="静态Fragment"
    android:gravity="center"
    android:onClick="staticFragment"
    android:layout_gravity="center_horizontal"
   android:textAllCaps="false"
   ></Button>


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAlignment="center"
        android:text="动态Fragment"
        android:gravity="center"
        android:layout_gravity="center_horizontal"
        android:textAllCaps="false"
        android:onClick="DynameicFragment"
        ></Button>




</LinearLayout>



activity_staticfragment.xml



<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".StaticFragmentActivity">

    <fragment
        android:id="@+id/staric"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.example.fragment.fragment.StaticFragment"
        tools:layout="@layout/fragment_static"
        ></fragment>

</LinearLayout>



fragment_dynameic.xml



<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".fragment.DynameicFragment">

    <!-- TODO: Update blank fragment layout -->
    <TextView


        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="这是动态fragment" />

</FrameLayout>



fragment_static.xml



<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".fragment.StaticFragment"
    >

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="这是静态fragment"
        android:gravity="center"/>


</FrameLayout>



 


 







展示效果




 


 


 




 


 




 


标签：Fragment,savedInstanceState,Bundle,fragment,ARG,import,public	

来源： https://www.cnblogs.com/zhaolei0419/p/16210631.html