How do I use getWindowManager() by another java file

android, window-managers

Solution

public String getWeithAndHeight(Context context, String url) {  
    DisplayMetrics dm = new DisplayMetrics();  
    ((Activity)context).getWindowManager().getDefaultDisplay().getMetrics(dm);
    //....
}

- getWindowManager() is a method of Activity class

Problem

I want to use getWindowManager() in my MainActivity, but I don't want to write this method directly in it. Here is my MainActivity code ``` public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); String d= new DisplayMessageActivity().getWeithAndHeight(d); } ``` and here is my DisplayMessageActivity code ``` public class DisplayMessageActivity extends Activity { @SuppressLint("NewApi") @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Intent intent = getIntent(); .... .... setContentView(textView); } public String getWeithAndHeight(String url) { DisplayMetrics dm = new DisplayMetrics(); *getWindowManager().getDefaultDisplay().getMetrics(dm);* int width = dm.widthPixels; int height = dm.heightPixels; String w=new String(""+width); String h=new String(""+height); url=url+"&23=w%3A"+w+"%20h%3A"+h+"%20d%3A"; return url; } } ``` my code break at getWindowManager(), please tell me why. Thank you very much.

Original source