Android - Standard height of toolbar
Its best to use ?attr/actionBarSize as @Jaison Brooks commented.
In the material guidelines, suggested height is 56dp:
Toolbar: 56dp
The recommended minimum size for touchable elements is 48 dp, see this page for more detailed metrics.
In addition to @vedant1811 answer, you can programmatically obtain actionBarSize from attrs:
TypedValue tv = new TypedValue();if (context.getTheme().resolveAttribute(android.R.attr.actionBarSize, tv, true)){ actionBarHeight = TypedValue.complexToDimensionPixelSize(tv.data, context.getResources().getDisplayMetrics());}