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Commit ff0d298a authored by Adam Powell's avatar Adam Powell
Browse files

Add API to block focus in the presence of a touchscreen 

For the sake of devices with touchscreens and optional keyboards, add
the touchscreenBlocksFocus attr and associated get/set methods to
ViewGroup. This will act much like FOCUS_BLOCKS_DESCENDANTS, but only
if the context reports that a touchscreen is present. This allows an
app to define much coarser-grained block elements for focus instead of
navigating between each individual (normally) focusable element, on
the theory that the readily available touchscreen or other keyboard
shortcuts allow for more fine-grained interaction. Keyboard focus
navigation thereby becomes more efficient at a coarse level.

Bug 13987814

Change-Id: Ie652b8845122a59046e96ad6074b3de163779adc
parent d3dc721c

api/current.txt

+3 −0
Original line number Diff line number Diff line
@@ -1283,6 +1283,7 @@ package android { 
    field public static final int topLeftRadius = 16843177; // 0x10101a9

    field public static final int topOffset = 16843352; // 0x1010258

    field public static final int topRightRadius = 16843178; // 0x10101aa

    field public static final int touchscreenBlocksFocus = 16843921; // 0x1010491

    field public static final int track = 16843631; // 0x101036f

    field public static final int transcriptMode = 16843008; // 0x1010100

    field public static final int transformPivotX = 16843552; // 0x1010320
@@ -33577,6 +33578,7 @@ package android.view { 
    method public android.animation.LayoutTransition getLayoutTransition();

    method public int getNestedScrollAxes();

    method public int getPersistentDrawingCache();

    method public boolean getTouchscreenBlocksFocus();

    method public int indexOfChild(android.view.View);

    method public final void invalidateChild(android.view.View, android.graphics.Rect);

    method public android.view.ViewParent invalidateChildInParent(int[], android.graphics.Rect);
@@ -33636,6 +33638,7 @@ package android.view { 
    method public void setOnHierarchyChangeListener(android.view.ViewGroup.OnHierarchyChangeListener);

    method public void setPersistentDrawingCache(int);

    method protected void setStaticTransformationsEnabled(boolean);

    method public void setTouchscreenBlocksFocus(boolean);

    method public void setTransitionGroup(boolean);

    method public boolean shouldDelayChildPressedState();

    method public boolean showContextMenuForChild(android.view.View);

core/java/android/view/View.java

+2 −1
Original line number Diff line number Diff line
@@ -7431,7 +7431,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback, 
        ViewParent ancestor = mParent;

        while (ancestor instanceof ViewGroup) {

            final ViewGroup vgAncestor = (ViewGroup) ancestor;

            if (vgAncestor.getDescendantFocusability() == ViewGroup.FOCUS_BLOCK_DESCENDANTS) {

            if (vgAncestor.getDescendantFocusability() == ViewGroup.FOCUS_BLOCK_DESCENDANTS

                    || vgAncestor.shouldBlockFocusForTouchscreen()) {

                return true;

            } else {

                ancestor = vgAncestor.getParent();

core/java/android/view/ViewGroup.java

+53 −4
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ package android.view; 


import android.animation.LayoutTransition;

import android.content.Context;

import android.content.pm.PackageManager;

import android.content.res.Configuration;

import android.content.res.TypedArray;

import android.graphics.Bitmap;
@@ -360,6 +361,11 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 


    static final int FLAG_IS_TRANSITION_GROUP_SET = 0x2000000;



    /**

     * When set, focus will not be permitted to enter this group if a touchscreen is present.

     */

    static final int FLAG_TOUCHSCREEN_BLOCKS_FOCUS = 0x4000000;



    /**

     * Indicates which types of drawing caches are to be kept in memory.

     * This field should be made private, so it is hidden from the SDK.
@@ -567,6 +573,9 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
                case R.styleable.ViewGroup_transitionGroup:

                    setTransitionGroup(a.getBoolean(attr, false));

                    break;

                case R.styleable.ViewGroup_touchscreenBlocksFocus:

                    setTouchscreenBlocksFocus(a.getBoolean(attr, false));

                    break;

            }

        }
@@ -660,6 +669,7 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
                // shortcut: don't report a new focusable view if we block our descendants from

                // getting focus

                && (getDescendantFocusability() != FOCUS_BLOCK_DESCENDANTS)

                && !shouldBlockFocusForTouchscreen()

                // shortcut: don't report a new focusable view if we already are focused

                // (and we don't prefer our descendants)

                //
@@ -901,7 +911,8 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
        }



        final int descendantFocusability = getDescendantFocusability();

        if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {

        if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS &&

                !shouldBlockFocusForTouchscreen()) {

            final int count = mChildrenCount;

            final View[] children = mChildren;
@@ -925,7 +936,8 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 


        final int descendantFocusability = getDescendantFocusability();



        if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {

        if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS &&

                !shouldBlockFocusForTouchscreen()) {

            final int count = mChildrenCount;

            final View[] children = mChildren;
@@ -941,13 +953,46 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
        // FOCUS_AFTER_DESCENDANTS and there are some descendants focusable.  this is

        // to avoid the focus search finding layouts when a more precise search

        // among the focusable children would be more interesting.

        if (descendantFocusability != FOCUS_AFTER_DESCENDANTS

        if ((descendantFocusability != FOCUS_AFTER_DESCENDANTS

                // No focusable descendants

                || (focusableCount == views.size())) {

                || (focusableCount == views.size())) && !shouldBlockFocusForTouchscreen()) {

            super.addFocusables(views, direction, focusableMode);

        }

    }



    /**

     * Set whether this ViewGroup should ignore focus requests for itself and its children.

     * If this option is enabled and the ViewGroup or a descendant currently has focus, focus

     * will proceed forward.

     *

     * @param touchscreenBlocksFocus true to enable blocking focus in the presence of a touchscreen

     */

    public void setTouchscreenBlocksFocus(boolean touchscreenBlocksFocus) {

        if (touchscreenBlocksFocus) {

            mGroupFlags |= FLAG_TOUCHSCREEN_BLOCKS_FOCUS;

            if (hasFocus()) {

                final View newFocus = focusSearch(FOCUS_FORWARD);

                if (newFocus != null) {

                    newFocus.requestFocus();

                }

            }

        } else {

            mGroupFlags &= ~FLAG_TOUCHSCREEN_BLOCKS_FOCUS;

        }

    }



    /**

     * Check whether this ViewGroup should ignore focus requests for itself and its children.

     */

    public boolean getTouchscreenBlocksFocus() {

        return (mGroupFlags & FLAG_TOUCHSCREEN_BLOCKS_FOCUS) != 0;

    }



    boolean shouldBlockFocusForTouchscreen() {

        return getTouchscreenBlocksFocus() &&

                mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN);

    }



    @Override

    public void findViewsWithText(ArrayList<View> outViews, CharSequence text, int flags) {

        super.findViewsWithText(outViews, text, flags);
@@ -2440,6 +2485,10 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
        }

        int descendantFocusability = getDescendantFocusability();



        if (shouldBlockFocusForTouchscreen()) {

            return false;

        }



        switch (descendantFocusability) {

            case FOCUS_BLOCK_DESCENDANTS:

                return super.requestFocus(direction, previouslyFocusedRect);

core/res/res/values/attrs.xml

+3 −0
Original line number Diff line number Diff line
@@ -2520,6 +2520,9 @@ 
            <enum name="blocksDescendants" value="2" />

        </attr>



        <!-- Set to true if this ViewGroup blocks focus in the presence of a touchscreen. -->

        <attr name="touchscreenBlocksFocus" format="boolean" />



        <!-- Sets whether this ViewGroup should split MotionEvents

             to separate child views during touch event dispatch.

             If false (default), touch events will be dispatched to

core/res/res/values/public.xml

+1 −0
Original line number Diff line number Diff line
@@ -2510,4 +2510,5 @@ 
       a view visibility changes. -->

  <public type="transition" name="slide_left"/>

  <public type="attr" name="multiArch" />

  <public type="attr" name="touchscreenBlocksFocus" />

</resources>