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Commit 8ccd7eb5 authored by Matt Casey's avatar Matt Casey
Browse files

TalkBack and switch access support for CropView 

- Switch to androidx ExploreByTouchHelper, add View pass-through calls.
- Add virtual view IDs for left/right bounds as well.
- Make content description describe the position (as a %)
- Allow volume buttons to move the current boundary along its axis
  (matching pattern used in Photos)
- Remove unused click action for boundaries (was breaking switch access)

Bug: 184018281
Bug: 184012364
Bug: 180062481
Bug: 184105678

Test: Enable talkback, move crop bounds with volume keys, same with
      switch access
Change-Id: I06bab02a37620f19e15cddcfc79ae858a1614e92
parent 54c39c71

packages/SystemUI/res/values/strings.xml

+8 −4
Original line number Diff line number Diff line
@@ -245,10 +245,14 @@ 
    <string name="screenshot_dismiss_description">Dismiss screenshot</string>

    <!-- Content description indicating that the view is a preview of the screenshot that was just taken [CHAR LIMIT=NONE] -->

    <string name="screenshot_preview_description">Screenshot preview</string>

    <!-- Content description for the top boundary of the screenshot being cropped [CHAR LIMIT=NONE] -->

    <string name="screenshot_top_boundary">Top boundary</string>

    <!-- Content description for the bottom boundary of the screenshot being cropped [CHAR LIMIT=NONE] -->

    <string name="screenshot_bottom_boundary">Bottom boundary</string>

    <!-- Content description for the top boundary of the screenshot being cropped, with the current position as a percentage. [CHAR LIMIT=NONE] -->

    <string name="screenshot_top_boundary_pct">Top boundary <xliff:g id="percent" example="50">%1$d</xliff:g> percent</string>

    <!-- Content description for the bottom boundary of the screenshot being cropped, with the current position as a percentage. [CHAR LIMIT=NONE] -->

    <string name="screenshot_bottom_boundary_pct">Bottom boundary <xliff:g id="percent" example="50">%1$d</xliff:g> percent</string>

    <!-- Content description for the left boundary of the screenshot being cropped, with the current position as a percentage. [CHAR LIMIT=NONE] -->

    <string name="screenshot_left_boundary_pct">Left boundary <xliff:g id="percent" example="50">%1$d</xliff:g> percent</string>

    <!-- Content description for the right boundary of the screenshot being cropped, with the current position as a percentage. [CHAR LIMIT=NONE] -->

    <string name="screenshot_right_boundary_pct">Right boundary <xliff:g id="percent" example="50">%1$d</xliff:g> percent</string>



    <!-- Notification title displayed for screen recording [CHAR LIMIT=50]-->

    <string name="screenrecord_name">Screen Recorder</string>

packages/SystemUI/src/com/android/systemui/screenshot/CropView.java

+153 −60
Original line number Diff line number Diff line
@@ -28,21 +28,26 @@ import android.os.Bundle; 
import android.os.Parcel;

import android.os.Parcelable;

import android.util.AttributeSet;

import android.util.IntArray;

import android.util.Log;

import android.util.MathUtils;

import android.util.Range;

import android.view.KeyEvent;

import android.view.MotionEvent;

import android.view.View;

import android.view.accessibility.AccessibilityEvent;

import android.view.accessibility.AccessibilityNodeInfo;

import android.widget.SeekBar;



import androidx.annotation.Nullable;

import androidx.core.view.ViewCompat;

import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;

import androidx.customview.widget.ExploreByTouchHelper;

import androidx.interpolator.view.animation.FastOutSlowInInterpolator;



import com.android.internal.widget.ExploreByTouchHelper;

import com.android.systemui.R;



import java.util.List;



/**

 * CropView has top and bottom draggable crop handles, with a scrim to darken the areas being

 * cropped out.
@@ -74,6 +79,7 @@ public class CropView extends View { 
    private Range<Float> mMotionRange;



    private CropInteractionListener mCropInteractionListener;

    private final ExploreByTouchHelper mExploreByTouchHelper;



    public CropView(Context context, @Nullable AttributeSet attrs) {

        this(context, attrs, 0);
@@ -94,7 +100,8 @@ public class CropView extends View { 
        // 48 dp touchable region around each handle.

        mCropTouchMargin = 24 * getResources().getDisplayMetrics().density;



        setAccessibilityDelegate(new AccessibilityHelper());

        mExploreByTouchHelper = new AccessibilityHelper();

        ViewCompat.setAccessibilityDelegate(this, mExploreByTouchHelper);

    }



    @Override
@@ -141,28 +148,7 @@ public class CropView extends View { 
                    mStartingX = event.getX();

                    mMovementStartValue = getBoundaryPosition(mCurrentDraggingBoundary);

                    updateListener(event);

                    switch (mCurrentDraggingBoundary) {

                        case TOP:

                            mMotionRange = new Range<>(0f,

                                    mCrop.bottom - pixelDistanceToFraction(mCropTouchMargin,

                                            CropBoundary.BOTTOM));

                            break;

                        case BOTTOM:

                            mMotionRange = new Range<>(

                                    mCrop.top + pixelDistanceToFraction(mCropTouchMargin,

                                            CropBoundary.TOP), 1f);

                            break;

                        case LEFT:

                            mMotionRange = new Range<>(0f,

                                    mCrop.right - pixelDistanceToFraction(mCropTouchMargin,

                                            CropBoundary.RIGHT));

                            break;

                        case RIGHT:

                            mMotionRange = new Range<>(

                                    mCrop.left + pixelDistanceToFraction(mCropTouchMargin,

                                            CropBoundary.LEFT), 1f);

                            break;

                    }

                    mMotionRange = getAllowedValues(mCurrentDraggingBoundary);

                }

                return true;

            case MotionEvent.ACTION_MOVE:
@@ -185,10 +171,30 @@ public class CropView extends View { 
        return super.onTouchEvent(event);

    }



    @Override

    public boolean dispatchHoverEvent(MotionEvent event) {

        return mExploreByTouchHelper.dispatchHoverEvent(event)

                || super.dispatchHoverEvent(event);

    }



    @Override

    public boolean dispatchKeyEvent(KeyEvent event) {

        return mExploreByTouchHelper.dispatchKeyEvent(event)

                || super.dispatchKeyEvent(event);

    }



    @Override

    public void onFocusChanged(boolean gainFocus, int direction,

            Rect previouslyFocusedRect) {

        super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);

        mExploreByTouchHelper.onFocusChanged(gainFocus, direction, previouslyFocusedRect);

    }



    /**

     * Set the given boundary to the given value without animation.

     */

    public void setBoundaryPosition(CropBoundary boundary, float position) {

        position = (float) getAllowedValues(boundary).clamp(position);

        switch (boundary) {

            case TOP:

                mCrop.top = position;
@@ -280,6 +286,28 @@ public class CropView extends View { 
        mCropInteractionListener = listener;

    }



    private Range getAllowedValues(CropBoundary boundary) {

        switch (boundary) {

            case TOP:

                return new Range<>(0f,

                        mCrop.bottom - pixelDistanceToFraction(mCropTouchMargin,

                                CropBoundary.BOTTOM));

            case BOTTOM:

                return new Range<>(

                        mCrop.top + pixelDistanceToFraction(mCropTouchMargin,

                                CropBoundary.TOP), 1f);

            case LEFT:

                return new Range<>(0f,

                        mCrop.right - pixelDistanceToFraction(mCropTouchMargin,

                                CropBoundary.RIGHT));

            case RIGHT:

                return new Range<>(

                        mCrop.left + pixelDistanceToFraction(mCropTouchMargin,

                                CropBoundary.LEFT), 1f);

        }

        return null;

    }



    private void updateListener(MotionEvent event) {

        if (mCropInteractionListener != null && (isVertical(mCurrentDraggingBoundary))) {

            float boundaryPosition = getBoundaryPosition(mCurrentDraggingBoundary);
@@ -371,6 +399,8 @@ public class CropView extends View { 


        private static final int TOP_HANDLE_ID = 1;

        private static final int BOTTOM_HANDLE_ID = 2;

        private static final int LEFT_HANDLE_ID = 3;

        private static final int RIGHT_HANDLE_ID = 4;



        AccessibilityHelper() {

            super(CropView.this);
@@ -384,62 +414,125 @@ public class CropView extends View { 
            if (Math.abs(y - fractionToVerticalPixels(mCrop.bottom)) < mCropTouchMargin) {

                return BOTTOM_HANDLE_ID;

            }

            return ExploreByTouchHelper.INVALID_ID;

            if (y > fractionToVerticalPixels(mCrop.top)

                    && y < fractionToVerticalPixels(mCrop.bottom)) {

                if (Math.abs(x - fractionToHorizontalPixels(mCrop.left)) < mCropTouchMargin) {

                    return LEFT_HANDLE_ID;

                }

                if (Math.abs(x - fractionToHorizontalPixels(mCrop.right)) < mCropTouchMargin) {

                    return RIGHT_HANDLE_ID;

                }

            }



            return ExploreByTouchHelper.HOST_ID;

        }



        @Override

        protected void getVisibleVirtualViews(IntArray virtualViewIds) {

        protected void getVisibleVirtualViews(List<Integer> virtualViewIds) {

            // Add views in traversal order

            virtualViewIds.add(TOP_HANDLE_ID);

            virtualViewIds.add(LEFT_HANDLE_ID);

            virtualViewIds.add(RIGHT_HANDLE_ID);

            virtualViewIds.add(BOTTOM_HANDLE_ID);

        }



        @Override

        protected void onPopulateEventForVirtualView(int virtualViewId, AccessibilityEvent event) {

            switch (virtualViewId) {

                case TOP_HANDLE_ID:

                    event.setContentDescription(

                            getResources().getString(R.string.screenshot_top_boundary));

                    break;

                case BOTTOM_HANDLE_ID:

                    event.setContentDescription(

                            getResources().getString(R.string.screenshot_bottom_boundary));

                    break;

            }

            CropBoundary boundary = viewIdToBoundary(virtualViewId);

            event.setContentDescription(getBoundaryContentDescription(boundary));

        }



        @Override

        protected void onPopulateNodeForVirtualView(int virtualViewId,

                AccessibilityNodeInfo node) {

            switch (virtualViewId) {

                case TOP_HANDLE_ID:

                    node.setContentDescription(

                            getResources().getString(R.string.screenshot_top_boundary));

                    setNodePositions(mCrop.top, node);

                    break;

                case BOTTOM_HANDLE_ID:

                    node.setContentDescription(

                            getResources().getString(R.string.screenshot_bottom_boundary));

                    setNodePositions(mCrop.bottom, node);

                    break;

            }

                AccessibilityNodeInfoCompat node) {

            CropBoundary boundary = viewIdToBoundary(virtualViewId);

            node.setContentDescription(getBoundaryContentDescription(boundary));

            setNodePosition(getNodeRect(boundary), node);



            // TODO: need to figure out the full set of actions to support here.

            node.addAction(

                    AccessibilityNodeInfo.AccessibilityAction.ACTION_CLICK);

            node.setClickable(true);

            node.setFocusable(true);

            // Intentionally set the class name to SeekBar so that TalkBack uses volume control to

            // scroll.

            node.setClassName(SeekBar.class.getName());

            node.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD);

            node.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD);

        }



        @Override

        protected boolean onPerformActionForVirtualView(

                int virtualViewId, int action, Bundle arguments) {

            if (action != AccessibilityNodeInfo.ACTION_SCROLL_FORWARD

                    && action != AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD) {

                return false;

            }

            CropBoundary boundary = viewIdToBoundary(virtualViewId);

            float delta = pixelDistanceToFraction(mCropTouchMargin, boundary);

            if (action == AccessibilityNodeInfo.ACTION_SCROLL_FORWARD) {

                delta = -delta;

            }

            setBoundaryPosition(boundary, delta + getBoundaryPosition(boundary));

            invalidateVirtualView(virtualViewId);

            sendEventForVirtualView(virtualViewId, AccessibilityEvent.TYPE_VIEW_SELECTED);

            return true;

        }



        private CharSequence getBoundaryContentDescription(CropBoundary boundary) {

            int template;

            switch (boundary) {

                case TOP:

                    template = R.string.screenshot_top_boundary_pct;

                    break;

                case BOTTOM:

                    template = R.string.screenshot_bottom_boundary_pct;

                    break;

                case LEFT:

                    template = R.string.screenshot_left_boundary_pct;

                    break;

                case RIGHT:

                    template = R.string.screenshot_right_boundary_pct;

                    break;

                default:

                    return "";

            }



            return getResources().getString(template,

                    Math.round(getBoundaryPosition(boundary) * 100));

        }



        private CropBoundary viewIdToBoundary(int viewId) {

            switch (viewId) {

                case TOP_HANDLE_ID:

                    return CropBoundary.TOP;

                case BOTTOM_HANDLE_ID:

                    return CropBoundary.BOTTOM;

                case LEFT_HANDLE_ID:

                    return CropBoundary.LEFT;

                case RIGHT_HANDLE_ID:

                    return CropBoundary.RIGHT;

            }

            return CropBoundary.NONE;

        }



        private void setNodePositions(float fraction, AccessibilityNodeInfo node) {

            int pixels = fractionToVerticalPixels(fraction);

            Rect rect = new Rect(0, (int) (pixels - mCropTouchMargin),

        private Rect getNodeRect(CropBoundary boundary) {

            Rect rect;

            if (isVertical(boundary)) {

                int pixels = fractionToVerticalPixels(getBoundaryPosition(boundary));

                rect = new Rect(0, (int) (pixels - mCropTouchMargin),

                        getWidth(), (int) (pixels + mCropTouchMargin));

                // Top boundary can sometimes go beyond the view, shift it down to compensate so

                // the area is big enough.

                if (rect.top < 0) {

                    rect.offset(0, -rect.top);

                }

            } else {

                int pixels = fractionToHorizontalPixels(getBoundaryPosition(boundary));

                rect = new Rect((int) (pixels - mCropTouchMargin),

                        (int) (fractionToVerticalPixels(mCrop.top) + mCropTouchMargin),

                        (int) (pixels + mCropTouchMargin),

                        (int) (fractionToVerticalPixels(mCrop.bottom) - mCropTouchMargin));

            }

            return rect;

        }



        private void setNodePosition(Rect rect, AccessibilityNodeInfoCompat node) {

            node.setBoundsInParent(rect);

            int[] pos = new int[2];

            getLocationOnScreen(pos);