How to inflate view inside fragment

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伪装坚强ぢ
伪装坚强ぢ 2020-12-01 10:04

If I try to inflate a view within a fragment I am getting NULL.. For example:

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                 


        
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  • 2020-12-01 10:55

    Declare the variable as a instance variable and then initialize Linear Layout

    LinearLayout linearLayout;
    
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment1, container, false);
        linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
        return rootView;
    }
    

    Then

    public void addPlaces() {
        Button button = new Button(getActivity());
        // needs activity context
        // fragment hosted by a activity. use getActivity() to get the context of the hosting activity. 
        button.setText("button name");
        linearlayout.addView(button);
    }
    

    Example: Modify the below according to your requirement.

    fragment1.xml

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    
        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:text="Button" />
    
        <LinearLayout
            android:layout_width="fill_parent"
            android:id="@+id/linearlayout"
            android:layout_height="fill_parent"
            android:layout_above="@+id/button1"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:orientation="vertical" >
        </LinearLayout>
    
    </RelativeLayout>
    

    Myfragment.java

    public class Myfragment extends Fragment {
    
        LinearLayout linearLayout;
        View rootView;
    
        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
            Button b = (Button) rootView.findViewById(R.id.button1);
            b.setOnClickListener(new OnClickListener() {
    
                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    addPlaces();
                }
    
            });
            linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            rootView = inflater.inflate(R.layout.fragment1, container, false);
            return rootView;
        }
    
        public void addPlaces() {
            Button button = new Button(getActivity()); // needs activity context
            button.setText("button name");
            linearLayout.addView(button);
        }
    }
    

    Snap shot of my emulator

    enter image description here

    Edit :

    activity-main.xml

    <RelativeLayout 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"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context=".MainActivity" >
    
         <fragment android:name="com.example.fragments.Myfragment"
                android:id="@+id/frag"
                android:layout_above="@+id/button1"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent" />
    
          <Button
              android:id="@+id/button1"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_alignParentBottom="true"
              android:layout_centerHorizontal="true"
              android:text="Button" />
    
    </RelativeLayout>
    

    MainActivity.java

    public class MainActivity extends FragmentActivity {
        Button b;
        Myfragment fragment;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragment = new Myfragment();
            fragmentTransaction.add(R.id.frag, fragment);
            fragmentTransaction.commit();
            b = (Button) findViewById(R.id.button1);
            b.setOnClickListener(new OnClickListener() {
    
                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    fragment.addPlaces();
                }
    
            });
        }
    }
    

    Myfragment.java

    public class Myfragment extends Fragment {
    
        LinearLayout linearLayout;
        View rootView;
    
        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
            linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            rootView = inflater.inflate(R.layout.fragment1, container, false);
            return rootView;
        }
    
        public void addPlaces() {
            Button button = new Button(getActivity()); // needs activity context
            button.setText("button name");
            linearLayout.addView(button);
        }
    }
    
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