How to get screen width and height

Question

I tried to use following code to get screen width and height in android app development:

Display display = getWindowManager().getDefaultDisplay();  int screenWidth = display.getWidth(); int screenHeight = display.getHeight(); 

but I got NullPointerException for my display, why? how to get screen width and height then?

Answer 1

If you're calling this outside of an Activity, you'll need to pass the context in (or get it through some other call). Then use that to get your display metrics:

DisplayMetrics metrics = context.getResources().getDisplayMetrics(); int width = metrics.widthPixels; int height = metrics.heightPixels; 

UPDATE: With API level 17+, you can use getRealSize:

Point displaySize = new Point(); activity.getWindowManager().getDefaultDisplay().getRealSize(displaySize); 

If you want the available window size, you can use getDecorView to calculate the available area by subtracting the decor view size from the real display size:

Point displaySize = new Point(); activity.getWindowManager().getDefaultDisplay().getRealSize(displaySize);  Rect windowSize = new Rect(); ctivity.getWindow().getDecorView().getWindowVisibleDisplayFrame(windowSize);  int width = displaySize.x - Math.abs(windowSize.width()); int height = displaySize.y - Math.abs(windowSize.height()); return new Point(width, height); 

getRealMetrics may also work (requires API level 17+), but I haven't tried it yet:

DisplayMetrics metrics = new DisplayMetrics(); activity.GetWindowManager().getDefaultDisplay().getRealMetrics(metrics); 

Answer 2

Within an activity, you can call:

int width = this.getResources().getDisplayMetrics().widthPixels; int height = this.getResources().getDisplayMetrics().heightPixels; 

When you're in a View, then you need to get the Context first:

int width = getContext().getResources().getDisplayMetrics().widthPixels; int height = getContext().getResources().getDisplayMetrics().heightPixels; 

This will work in all Android version, available since API 1, and never deprecated.