Authorative way to override onMeasure()?

Question

What\'s the correct way of overriding onMeasure()? I\'ve seen various approaches. For example, Professional Android Development uses MeasureSpec to calculate the di

Answer 1

I think it depends on the parent which you are overriding.

For example, if you are extending a ViewGroup (like FrameLayout), when you have measured the size, you should call like below

super.onMeasure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
                MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));

because you may want to ViewGroup to do rest work (do some stuffs on child view)

If you are extending a View (like ImageView), you can just call this.setMeasuredDimension(width, height);, because the parent class will just do something like you have done usually.

In a word, if you want some features your parent class offers free you should call super.onMeasure() (pass MeasureSpec.EXACTLY mode measure spec usually), otherwise call this.setMeasuredDimension(width, height); is enough.