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,
                 


        
1条回答
  •  栀梦
    栀梦 (楼主)
    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

    
    
    
        

    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

    
    
         
    
          

    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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