From 5a5df7f936ffbe2ba24ecba821976b76ff6b26a2 Mon Sep 17 00:00:00 2001 From: quddusc Date: Fri, 6 Sep 2013 11:18:27 -0700 Subject: [PATCH] docs: Fixed deprecated value. Bug: 10641906 Change-Id: I1e89e031292fb225f67c7f8a06924f29a9e950b2 --- .../html/guide/topics/ui/how-android-draws.jd | 115 ++++++++++++------ 1 file changed, 75 insertions(+), 40 deletions(-) diff --git a/docs/html/guide/topics/ui/how-android-draws.jd b/docs/html/guide/topics/ui/how-android-draws.jd index 6a8cd869e535d..168f77b265cfa 100644 --- a/docs/html/guide/topics/ui/how-android-draws.jd +++ b/docs/html/guide/topics/ui/how-android-draws.jd @@ -4,15 +4,19 @@ parent.link=index.html @jd:body -

When an Activity receives focus, it will be requested to draw its layout. -The Android framework will handle the procedure for drawing, but the Activity must provide +

When an {@link android.app.Activity} receives focus, it will be requested to +draw its layout. +The Android framework will handle the procedure for drawing, but the +{@link android.app.Activity} must provide the root node of its layout hierarchy.

Drawing begins with the root node of the layout. It is requested to measure and -draw the layout tree. Drawing is handled by walking the tree and rendering each View that - intersects the invalid region. In turn, each View group is responsible for requesting -each of its children to be drawn (with the {@link android.view.View#draw(Canvas) draw()} method) -and each View is responsible for drawing itself. +draw the layout tree. Drawing is handled by walking the tree and rendering each +{@link android.view.View} that intersects the invalid region. In turn, each +{@link android.view.ViewGroup} is responsible for requesting +each of its children to be drawn +(with the {@link android.view.View#draw(Canvas) draw()} method) +and each {@link android.view.View} is responsible for drawing itself. Because the tree is traversed in-order, this means that parents will be drawn before (i.e., behind) their children, with siblings drawn in the order they appear in the tree. @@ -20,76 +24,107 @@ and each View is responsible for drawing itself.

-

The framework will not draw Views that are not in the invalid region, and also - will take care of drawing the Views background for you.

-

You can force a View to draw, by calling {@link android.view.View#invalidate()}. +

The framework will not draw {@link android.view.View} objects that are not +in the invalid region, and also + will take care of drawing the {@link android.view.View} background for you.

+

You can force a {@link android.view.View} to draw, by calling +{@link android.view.View#invalidate()}.

- Drawing the layout is a two pass process: a measure pass and a layout pass. The measuring - pass is implemented in {@link android.view.View#measure(int, int)} and is a top-down traversal - of the View tree. Each View pushes dimension specifications down the tree - during the recursion. At the end of the measure pass, every View has stored + Drawing the layout is a two pass process: a measure pass and a layout pass. +The measuring pass is implemented in {@link android.view.View#measure(int, int)} +and is a top-down traversal of the {@link android.view.View} tree. Each {@link android.view.View} +pushes dimension specifications down the tree + during the recursion. At the end of the measure pass, every +{@link android.view.View} has stored its measurements. The second pass happens in - {@link android.view.View#layout(int,int,int,int)} and is also top-down. During + {@link android.view.View#layout(int,int,int,int)} and is also top-down. During this pass each parent is responsible for positioning all of its children using the sizes computed in the measure pass.

- When a View's measure() method returns, its {@link android.view.View#getMeasuredWidth()} and - {@link android.view.View#getMeasuredHeight()} values must be set, along with those for all of - that View's descendants. A View's measured width and measured height values - must respect the constraints imposed by the View's parents. This guarantees + When a {@link android.view.View} object's +{@link android.view.View#measure(int, int) measure()} method +returns, its {@link android.view.View#getMeasuredWidth()} and + {@link android.view.View#getMeasuredHeight()} values must be set, along + with those for all of that {@link android.view.View} object's descendants. +A {@link android.view.View} object's measured width and +measured height values must respect the constraints imposed by the +{@link android.view.View} object's parents. This guarantees that at the end of the measure pass, all parents accept all of their - children's measurements. A parent View may call measure() more than once on + children's measurements. A parent {@link android.view.View} may call +{@link android.view.View#measure(int, int) measure()} more than once on its children. For example, the parent may measure each child once with unspecified dimensions to find out how big they want to be, then call - measure() on them again with actual numbers if the sum of all the children's - unconstrained sizes is too big or too small (i.e., if the children don't agree among themselves - as to how much space they each get, the parent will intervene and set the rules on the second pass). + {@link android.view.View#measure(int, int) measure()} on them again with +actual numbers if the sum of all the children's + unconstrained sizes is too big or too small (that is, if the children +don't agree among themselves + as to how much space they each get, the parent will intervene and set +the rules on the second pass).

- To initiate a layout, call {@link android.view.View#requestLayout}. This method is typically - called by a View on itself when it believes that is can no longer fit within + To initiate a layout, call {@link android.view.View#requestLayout}. +This method is typically + called by a {@link android.view.View} on itself +when it believes that is can no longer fit within its current bounds.

The measure pass uses two classes to communicate dimensions. The - {@link android.view.ViewGroup.LayoutParams} class is used by Views to tell their parents how they - want to be measured and positioned. The base LayoutParams class just - describes how big the View wants to be for both width and height. For each + {@link android.view.ViewGroup.LayoutParams} class is used by +{@link android.view.View} objects to tell their parents how they + want to be measured and positioned. The base +{@link android.view.ViewGroup.LayoutParams} class just + describes how big the {@link android.view.View} wants to be for both +width and height. For each dimension, it can specify one of:

-

There are subclasses of LayoutParams for different subclasses of ViewGroup. - For example, RelativeLayout has its own subclass of LayoutParams, which includes - the ability to center child Views horizontally and vertically. +

There are subclasses of {@link android.view.ViewGroup.LayoutParams} for +different subclasses of {@link android.view.ViewGroup}. + For example, {@link android.widget.RelativeLayout} has its own subclass of +{@link android.view.ViewGroup.LayoutParams}, which includes + the ability to center child {@link android.view.View} objects +horizontally and vertically.

- MeasureSpecs are used to push requirements down the tree from parent to - child. A MeasureSpec can be in one of three modes:

+ {@link android.view.View.MeasureSpec MeasureSpec} objects are used to push +requirements down the tree from parent to + child. A {@link android.view.View.MeasureSpec MeasureSpec} can be in one of +three modes: