Dynamic addition of Fragment

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The dynamic loading of fragments is mainly divided into 5 steps

1. Create a shard instance.

2. Get FragmentManager.

3. Start the transaction.

4. Add fragments to the container.

5. Commit the transaction.

code demo

In this example, the left side is static loading, and the right side is dynamic loading

Show static loading on the left

left_fragment.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorAccent">            
    <Button
android:onClick="anotherRight"
android:id="@+id/button"
android:layout_gravity="center_horizontal"
android:text="This is button in left_fragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />                                                
</LinearLayout>

LeftFragment.class

public class LeftFragment extends Fragment {
 //     Rewrite onCreateView method
 @Nullable
     @Override
 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
 //         The data type here is View , so just return inflater to
 return inflater.inflate(R.layout.left_fragment , container, false );
                
    }

}

Dynamic addition on the right

another_right_fragment.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary">
< TextView
 android :id= "@+id/textview"
 android :layout_gravity= "center_horizontal"
 android :text= " This is a dynamically added fragment "
 android :layout_width= "wrap_content"
 android :layout_height= "wrap_content" />                    
</LinearLayout>

AnotherRightFragment.class

public class AnotherRightFragment extends Fragment {
 //     Override the onCreateView method
 @Nullable
     @Override
 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
 //         The data type here is View , so return the inflater directly
 inflater.inflate (R.layout.another_right_fragment,container, false );
                
    }
}

also need to be rewritten

just changed in the main activity

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <!--注意，fragment必须要有id，否则无法编译-->
    <fragment
        android:id="@+id/left_fragment"
        android:name="com.loser.fragmenttext.LeftFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1" />

    <!--注意，这里不是fragment，是用来填充的一个布局-->
    <FrameLayout
        android:id="@+id/right_layout"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="0" />
</LinearLayout>

最主要的代码，在主活动中实现碎片的动态加载

MainActivity.class

public class MainActivity extends AppCompatActivity {
    FragmentManager fragmentManager;
    FragmentTransaction fragmentTransaction;
    FrameLayout frameLayout;

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

//    左边碎片中的按钮绑定的事件
    public void anotherRight(View v){
//         FragmentManager
        fragmentManager = getSupportFragmentManager();
//        通过begin开启事务
        fragmentTransaction = fragmentManager.beginTransaction();
//        使用replace向容器内添加碎片
        fragmentTransaction.replace(R.id.right_layout,new AnotherRightFragment());
//        将事务添加到返回栈中
        fragmentTransaction.addToBackStack(null);
//        拿到FrameLayout以便在设置其大小
        frameLayout = (FrameLayout)findViewById(R.id.right_layout);
//        重新设置右碎片的布局
        frameLayout.setLayoutParams(new LinearLayout.LayoutParams(0,MATCH_PARENT, 2.0f));
//        提交事务
        fragmentTransaction.commit();
//        土司一下，证明你点击有效
        Toast.makeText(MainActivity.this,"你点击了按钮",Toast.LENGTH_SHORT).show();
    }
}

此处

//        将事务添加到返回栈中
        fragmentTransaction.addToBackStack(null);

是当用户按下Back后就直接退出活动了，而如上设置为null则返回到上一个碎片。

至此，动态添加碎片的基本方法已经结束。

Dynamic addition of Fragment, dynamic loading of Fragment