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Avoid duplicate measurements for children #46

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thagikura opened this issue May 24, 2016 · 3 comments · Fixed by #514
Closed

Avoid duplicate measurements for children #46

thagikura opened this issue May 24, 2016 · 3 comments · Fixed by #514
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@thagikura
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enhancement workload mid

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@thagikura
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thagikura commented May 24, 2016 •
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In the onMeasure method, child.measure may be called more than once (e.g. Called first in the first loop to determine the number of flex lines, then called later to be expanded/shrank based on flexGrow/flexShrink attributes also maybe called to be stretched based on alignItems/alignSelf attributes).

This may cause performance issue especially the child is a nested ViewGroup.
It will be efficient to defer the child.measure as much as possible to reduce the number of measurements of the same child.
@thagikura thagikura self-assigned this May 24, 2016
@thagikura thagikura mentioned this issue Apr 17, 2017
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@jiasonwang
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Flexbox nested flexbox will cause performance degradation,too much measure

@aitorvs
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aitorvs commented Sep 25, 2019

Do you have any updates on this issue?

thagikura added a commit that referenced this issue Oct 24, 2019
@thagikura
WIP: Attempt to fix #46
1e3ccb7 
This PR prevents the number of measure calls for the children of the
Flexbox.
If any items in a FlexLine don't have the flexGrow or flexShrink
attributes set, the children in the FlexLine don't have to be measured
in the FlexboxHelper#determineMainSize method.

Similarly, if the AlignItems attribute for the Flexbox is not equal to
AlignItems.STRETCH nor any items in a FlexLine don't have the
AlignSelf.STRETCH attributes, the items in the FlexLine don't have to be
measured in the FlexboxHelpers#stretchViews method.

Also this PR changes the default values of FlexboxLayout as follows:
- mAlignItems: STRETCH -> FLEX_START
- mAlignContent: STRETCH -> FLEX_START
thagikura added a commit that referenced this issue Oct 24, 2019
@thagikura
WIP: Attempt to fix #46
ca711f5 
This PR prevents the number of measure calls for the children of the
Flexbox.
If any items in a FlexLine don't have the flexGrow or flexShrink
attributes set, the children in the FlexLine don't have to be measured
in the FlexboxHelper#determineMainSize method.

Similarly, if the AlignItems attribute for the Flexbox is not equal to
AlignItems.STRETCH nor any items in a FlexLine don't have the
AlignSelf.STRETCH attributes, the items in the FlexLine don't have to be
measured in the FlexboxHelpers#stretchViews method.

Also this PR changes the default values of FlexboxLayout as follows:
- mAlignItems: STRETCH -> FLEX_START
- mAlignContent: STRETCH -> FLEX_START
@thagikura thagikura mentioned this issue Oct 28, 2019
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@thagikura
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I think this can be now closed. #514 should remove the unnecessary measure calls.

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@thagikura thagikura

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Reduce the number of measure calls for children of Flexbox google/flexbox-layout
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@thagikura @jiasonwang @aitorvs