How does setting baselineAligned to false improve performance in LinearLayout?
AndroidListviewAndroid LintAndroid Problem Overview
I was just building some UI in xml, and Lint gave me a warning and said to set android:baselineAligned to false to improve performance in ListView.
The docs for the Lint changes that added this warning say
> Layout performance: Finds LinearLayouts with weights where you should > set android:baselineAligned="false" for better performance, and also > finds cases where you have nested weights which can cause performance > problems.
Can somebody explain why this improves performance, specifically when weight is involved?
Android Solutions
Solution 1 - Android
By setting android:baselineAligned="false" , you're preventing the extra work your app's layout has to do in order to Align its children's baselines; which can obviously increase the performance. (Fewer unnecessary operations on UI => Better performance)
Solution 2 - Android
how android:baselineAligned="false" help . It may not be the answer but help to get concept.
> I've just managed to get 3 items (icon, text, button) centered > vertically in horizontal LinearLayout. > > This may seem simple, but in reality specifying > android:gravity="center_vertical" as LinearLayout attribute is not > enough - icon is centered, but text and button are not. This is > because (presumably) text have a baseline, and centering algorithm > uses it instead of 'real' vertical center. But what is worse - button > (which comes next to text) is centered using text's baseline! > > Specifying android:baselineAligned="false" in LinearLayout turns this > off, and everything centers correctly.
Solution 3 - Android
// Baseline alignment requires to measure widgets to obtain the
// baseline offset (in particular for TextViews). The following
// defeats the optimization mentioned above. Allow the child to
// use as much space as it wants because we can shrink things
// later (and re-measure).
if (baselineAligned) {
final int freeSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
child.measure(freeSpec, freeSpec);
}