Android, How to get Width and Height of ViewGroup?

Question

In my app I need to know what is the size of main container of activity. I have written following code:

Button btnActionMenu = (Button) findViewById(R.id.actionbar_menu);
        btnActionMenu.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                int width = (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 40, getResources().getDisplayMetrics());
                RelativeLayout rlContainer = (RelativeLayout) findViewById(R.id.inner_content);
                Bitmap bitmap = Bitmap.createBitmap(rlContainer.getLayoutParams().width, rlContainer.getLayoutParams().height, Config.ARGB_8888);//
                Canvas canvas = new Canvas(bitmap);
                rlContainer.draw(canvas);
                SlideoutHelper.setBitmap(bitmap, width);
                startActivity(new Intent(Home.this, MenuActivity.class));
                overridePendingTransition(0, 0); 
            }
        });

rlContainer is the root container of activity. When I run and click on button, the application crashes and Logcat says "Application Null pointer exception" and points to line

Bitmap bitmap = Bitmap.createBitmap(rlContainer.getLayoutParams().width, rlContainer.getLayoutParams().height, Config.ARGB_8888);

any suggestion would be appreciated. Thanks

score 0 · Answer 1 · answered May 12 '12 at 19:19

0

try this :

    v.measure(
    MeasureSpec.makeMeasureSpec(v.getLayoutParams().width,MeasureSpec.EXACTLY),
    MeasureSpec.makeMeasureSpec(v.getLayoutParams().height, MeasureSpec.EXACTLY));
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
    Bitmap bitmap = Bitmap.createBitmap(v.getWidth(), v.getHeight()
   ,Bitmap.Config.RGB_565);

answered May 12 '12 at 19:19

ρяσѕρєя K

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Thanks dear Imran, but the result was same with Null pointer message which points to second line of your code. I have no idea why its like this!!! Thanks – Hesam May 12 '12 at 19:26
you are using rlContainer or v? – ρяσѕρєя K May 12 '12 at 19:31

android developer · Answer 2 · 2012-05-12T20:31:28.637

have you tried getMeasuredHeight and getMeasuredWidth , or getHeight and getWidth (on the rlContainer variable ) ?

note that this works only after the view was prepared , and not inside the onCreate() method . however , it will work on this situation since it's inside a user-related action , which occurs after the views were shown to the user.

btw , about your code , "rlContainer.getLayoutParams().width" might return a negative value , in case it's wrap-content or match-parent .

Android, How to get Width and Height of ViewGroup?

2 Answers2