Layout being measured twice, what could be the issue?

Question

I am using the following layouts:

<merge
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

    <VideoView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <ProgressBar
        android:visibility="invisible"
        android:id="@+id/progress"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <LinearLayout
        android:id="@+id/llSearch"
        android:visibility="visible"
        android:background="#50AAAAAA"
        android:paddingTop="10dp"
        android:gravity="center_vertical"
        android:paddingBottom="10dp"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="72dp">

        <ImageView
            android:layout_marginLeft="16dp"
            android:layout_marginStart="16dp"
            android:src="@drawable/abc_ic_search_api_mtrl_alpha"
            android:layout_width="40dp"
            android:layout_height="40dp" />

        <EditText
            android:textColor="@android:color/white"
            android:textColorHint="@android:color/white"
            android:background="@android:color/transparent"
            android:visibility="visible"
            android:maxLines="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </LinearLayout>

    <android.support.v7.widget.RecyclerView
        android:visibility="invisible"
        android:layout_marginTop="72dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <android.support.v7.widget.RecyclerView
        android:visibility="gone"
        android:layout_marginTop="72dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <com.myapp.custom.RevealView
        android:id="@+id/reveal"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</merge>

When running the app through DDMS, I've noticed that the layout ends up being measured twice, why is this and how can I prevent overdraw?

What's also strange is that I can't figure out where the other LinearLayouts are coming from.

score 0 · Answer 1 · answered Sep 01 '16 at 23:49

0

Measuring twice isnt overdraw. Depending on the type of layout you're using Android might need to measure it twice because of the relationship between child views require it. This can happen with layouts like LinearLayout or RelativeLayout. For exact reason you need to check the source of those, but its hardly an issue (usually).

But if you have something like a recycleview you should avoid using big nested layouts inside.

answered Sep 01 '16 at 23:49

breakline

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Just look at the hierarchy: FrameLayout -> LinearLayout -> FrameLayout -> LinearLayout -> THEN my XML Where are those other FrameLayout -> LinearLayout coming from? – AndyRoid Sep 01 '16 at 23:50
Maybe it is part of the phone's `DecorView`? – AndyRoid Sep 01 '16 at 23:56
Android adds layouts automatically. Your "root" layout is mabye 3-4 levels under the real root. Do not worry abou that. – breakline Sep 02 '16 at 01:04
Sounds like a lot of "magic" to me, my job is to worry about that – AndyRoid Sep 02 '16 at 01:04
No it's not, its part of how the framework works. Check out "decorview" in google. – breakline Sep 02 '16 at 01:07
Alternatively you can read this: http://www.curious-creature.com/2009/03/04/speed-up-your-android-ui/ – breakline Sep 02 '16 at 01:08

Layout being measured twice, what could be the issue?

1 Answers1