How to use getActivity () method in Fragment?

This code takes off for me java.lang.RuntimeException: Unable to start activity ComponentInfo

public class Fragment1 extends Fragment { public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = inflater.inflate(R.layout.fragment1, null); Button button = (Button) v.findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { ((Button)getActivity().findViewById(R.id.btnFind)).setText("Access from Fragment1"); } }); return v; } }

Activity.java

  public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);//java.lang.RuntimeException: Unable to start activity ComponentInfo } }

activity_main.xml

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/LinearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <Button android:id="@+id/btnFind" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="onClick" android:text="find"> </Button> <fragment android:id="@+id/fragment1" android:name="com.my_research_app.fragment_getactivity2.Fragment1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" tools:layout="@layout/fragment1"> </fragment> <FrameLayout android:id="@+id/fragment2" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1"> </FrameLayout> </LinearLayout>

}

fragment1.xml

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#77ff0000" android:orientation="vertical"> <TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="frag1_text"> </TextView> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="log"> </Button> </LinearLayout>
  • you cannot get the View fragment from the activit in this way and the getActivity() method has nothing to do with it / It returns the current instance of the activity class in which the fragment is located, not its markup - pavlofff
  • java.lang.RuntimeException: Unable to start activity ComponentInfo says practically nothing. Show the full stack trace. - post_zeew
  • If I change the MainActivity inheritance from Acttivity to FragmentActivity, then this code works although in the source code of the andA getActivity () method there is neither in Activity nor in FragmentActivity (in the source code class FragmentActivity extends Activity). getActivity () - defined in the class Fragmet - so why oh why then this happens? - mtb

1 answer 1

No need to get to the activation widget, it should do it herself.

Make an activation method like

 public void showSomething() { yourView.setText("hello"); }

And in the fragment, call this method:

  ((MainActivity)getActivity()).showSomething();
  • Error: (183, 35) error: incompatible types: FragmentActivity cannot be converted to MainActivity - mtb
  • It is necessary to lead to the class of the activit in which showSomething () is defined, and which uses this fragment. - tse