CODEWITHSUNDEEP
androidperformanceandroid-layout
LuLeBe
LuLeBe

Reputation: 584

How does match_parent work?

As far as I've understood Android's View rendering process, the root Layout will start the measurement and ask each of its children for it's size. If one of them is a Viewgroup itself, it will again ask the children, which either just return their set size, or calculate it if they're set to wrap_content.

Now how does that work with match_parent? The view can't calculate it's size since it has to know the parent's size first, right? So the parent would have to calculate it's own size and then send that to the child, which then can go on with it's own layout. Does that make match_parent a little more inefficient than wrap_content or even fixed dp-values?

Upvotes: 0

Views: 98

Answers (1)

suitianshi
suitianshi

Reputation: 3340

Actually, match_parent says that "Hi parent, I want to be as big as your left available space".For example, if ViewGroup Parent has two children: child A at index 0 with wrap_content and child B at index 1 with match_parent. And A says he wants to be 100px wide, then the width of B will be : total width of Parent - padding of Parent - margin of A - 100px - margin of B

Upvotes: 1

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