Getting java.lang.NullpointerException while trying to call SetContentView() in android

Question

I am calling a method of an activity class from another activity class.In the method i am calling setContentView() passing another xml file(Diffrent xml than the one i am displaying in my first class(calling class).So while calling setContentView(),iam getting null pointerException. Please find my code below: Calling class

mainListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {



    DisplayMessageActivity d=new DisplayMessageActivity();
    try {
        Toast.makeText(CallWebserviceActivity.this, "position"+position, Toast.LENGTH_SHORT).show();

        d.showmessage(arrays, position,CallWebserviceActivity.this);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

});

New class where setContentView() is called:

public class DisplayMessageActivity extends Activity {

public void showmessage(ArrayList<JSONObject> arrays,int position,Context context) throws Exception {

 RelativeLayout relatelayout;

    setContentView(R.layout.showdetails);

    Toast.makeText(DisplayMessageActivity.this, "DisplayMessageActivity", Toast.LENGTH_SHORT).show();




}

score 2 · Answer 1 · answered Nov 03 '15 at 16:53

The main problem is DisplayMessageActivity d=new DisplayMessageActivity();. Activities shouldn't be created by you, but by the framework using an Intent with information describing your target component, and startActivity(Intent). Also, generally you set your content view in onCreate().

It looks like you might be trying to follow this example? http://developer.android.com/training/basics/firstapp/starting-activity.html

Getting java.lang.NullpointerException while trying to call SetContentView() in android

1 Answers1