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Commit 6ab02c1f authored by yingleiw's avatar yingleiw
Browse files

Adopt the accessibility state api in progress bar 

When the progress changes, instead of sending TYPE_VIEW_SELECTED event,
CONTENT_CHANGE_TYPE_STATE_DESCRIPTION event sent. Developers can
override onInitializeAccessibilityNodeInfo() and call
info.setStateDescription() to provide customized state description.

Bug: 123346875
Test: The default implementation of StateDescriptionFormatter maintains
the current format talkback uses. Also tested on talkback_test to set
customized state description based on progress.
Note: this change should not be merged until CL/275509401 (google3) is merged.

Change-Id: I8f1a0c91c55a498593c360483827ed050656d943
parent 34c56f79

core/java/android/widget/ProgressBar.java

+50 −2
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ import android.widget.RemoteViews.RemoteView; 


import com.android.internal.R;



import java.text.NumberFormat;

import java.util.ArrayList;



/**
@@ -241,6 +242,8 @@ public class ProgressBar extends View { 


    private boolean mAggregatedIsVisible;



    private CharSequence mCustomStateDescription = null;



    private final ArrayList<RefreshData> mRefreshData = new ArrayList<RefreshData>();



    /**
@@ -1551,9 +1554,54 @@ public class ProgressBar extends View { 
        }

    }



    private float getPercent(int progress) {

        final float maxProgress = getMax();

        final float minProgress = getMin();

        final float currentProgress = progress;

        final float diffProgress = maxProgress - minProgress;

        if (diffProgress <= 0.0f) {

            return 0.0f;

        }

        final float percent = (currentProgress - minProgress) / diffProgress;

        return Math.max(0.0f, Math.min(1.0f, percent));

    }



    /**

     * Default percentage format of the state description based on progress, for example,

     * "50 percent".

     *

     * @param progress the progress value, between {@link #getMin()} and {@link #getMax()}

     * @return state description based on progress

     */

    private CharSequence formatStateDescription(int progress) {

        return NumberFormat.getPercentInstance(mContext.getResources().getConfiguration().locale)

                .format(getPercent(progress));

    }



    /**

     * This function is called when an instance or subclass sets the state description. Once this

     * is called and the argument is not null, the app developer will be responsible for updating

     * state description when progress changes and the default state description will not be used.

     * App developers can restore the default behavior by setting the argument to null. If set

     * progress is called first and then setStateDescription is called, two state change events

     * will be merged by event throttling and we can still get the correct state description.

     *

     * @param stateDescription The state description.

     */

    @Override

    public void setStateDescription(@Nullable CharSequence stateDescription) {

        mCustomStateDescription = stateDescription;

        if (stateDescription == null) {

            super.setStateDescription(formatStateDescription(mProgress));

        } else {

            super.setStateDescription(stateDescription);

        }

    }



    void onProgressRefresh(float scale, boolean fromUser, int progress) {

        if (AccessibilityManager.getInstance(mContext).isEnabled()) {

            sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_SELECTED);

        if (AccessibilityManager.getInstance(mContext).isEnabled()

                && mCustomStateDescription == null) {

            super.setStateDescription(formatStateDescription(mProgress));

        }

    }