布局layout_weight和wrap_content

Question

Is it standard to use ( android:layout_weight="1" , android:layout_height="0dp" ) and ( android:layout_height="wrap_content" ) for two elements in one container with android:weightSum="1"

I checked in android 4 , 6 , 8 and I didn't seen any problem but my question:

If one of elements feel the whole weightSum how other element can be visible ?

I use this layout to have a bottom menu in a layout that can be visible and invisible.

like this :

<LinearLayout
    android:orientation="vertical" 
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:weightSum="1"
    >

 <LinearLayout
 android:orientation="vertical" 
 android:layout_weight="1"
 android:layout_width="match_parent"
 android:layout_height="0dp">
 </LinearLayout>

 <LinearLayout
 android:orientation="vertical" 
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Ok"
                    />
 </LinearLayout>

</LinearLayout>

Answer 1

weight means a specified value from REMAINING space ...means that your view is 1 weight so every remaining space take your view...(remaining means all over view consider their height of width screen and after left space is remaining space in screen...counted by your linear layout oriantation ) that's all space consider in your 1 weight

refer this official document

Answer 2

I didn't seen any problem but my question is if one of elements feel the whole weightSum how other element can be visible ?

It's actually not using the whole weightsum. Putting android:layout_weight="1" with height as 0 means that it will first check if any other layout want to use some height defined as wrap_content and after that whatever place exists it will make the remaining height of the targets first layout.