From 6033c0817427386cd3e95a992d1f34dad4188f96 Mon Sep 17 00:00:00 2001
From: Svetoslav Ganov <svetoslavganov@google.com>
Date: Tue, 25 Oct 2011 13:45:04 -0700
Subject: [PATCH] Adding accessibility support to the tablet swipe unlock.

1. Added handling for hover events that are transformed into
   touch events and given to the touch event handling code
   if accessibility is enabled.

2. Now swiping across the handle unlocks the device for both
   cases - accessibility enabled or disabled.

bug:5513324

Change-Id: I7031690d69b1a2737e2ce4d1871d69d7dfbf3006
---
 .../com/android/internal/widget/WaveView.java | 90 ++++++++++++++++---
 core/res/res/values/strings.xml               |  3 +
 2 files changed, 82 insertions(+), 11 deletions(-)

diff --git a/core/java/com/android/internal/widget/WaveView.java b/core/java/com/android/internal/widget/WaveView.java
index 288865f30a127..2d89234000a72 100644
--- a/core/java/com/android/internal/widget/WaveView.java
+++ b/core/java/com/android/internal/widget/WaveView.java
@@ -26,10 +26,13 @@ import android.graphics.BitmapFactory;
 import android.graphics.Canvas;
 import android.graphics.drawable.BitmapDrawable;
 import android.os.Vibrator;
+import android.text.TextUtils;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
 
 import com.android.internal.R;
 
@@ -64,6 +67,18 @@ public class WaveView extends View implements ValueAnimator.AnimatorUpdateListen
     private static final long DELAY_INCREMENT2 = 12; // increment per wave while not tracking
     private static final long WAVE_DELAY = WAVE_DURATION / WAVE_COUNT; // initial propagation delay
 
+    /**
+     * The scale by which to multiply the unlock handle width to compute the radius
+     * in which it can be grabbed when accessibility is disabled.
+     */
+    private static final float GRAB_HANDLE_RADIUS_SCALE_ACCESSIBILITY_DISABLED = 0.5f;
+
+    /**
+     * The scale by which to multiply the unlock handle width to compute the radius
+     * in which it can be grabbed when accessibility is enabled (more generous).
+     */
+    private static final float GRAB_HANDLE_RADIUS_SCALE_ACCESSIBILITY_ENABLED = 1.0f;
+
     private Vibrator mVibrator;
     private OnTriggerListener mOnTriggerListener;
     private ArrayList<DrawableHolder> mDrawables = new ArrayList<DrawableHolder>(3);
@@ -450,6 +465,27 @@ public class WaveView extends View implements ValueAnimator.AnimatorUpdateListen
         }
     };
 
+    @Override
+    public boolean onHoverEvent(MotionEvent event) {
+        if (AccessibilityManager.getInstance(mContext).isTouchExplorationEnabled()) {
+            final int action = event.getAction();
+            switch (action) {
+                case MotionEvent.ACTION_HOVER_ENTER:
+                    event.setAction(MotionEvent.ACTION_DOWN);
+                    break;
+                case MotionEvent.ACTION_HOVER_MOVE:
+                    event.setAction(MotionEvent.ACTION_MOVE);
+                    break;
+                case MotionEvent.ACTION_HOVER_EXIT:
+                    event.setAction(MotionEvent.ACTION_UP);
+                    break;
+            }
+            onTouchEvent(event);
+            event.setAction(action);
+        }
+        return super.onHoverEvent(event);
+    }
+
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         final int action = event.getAction();
@@ -460,21 +496,12 @@ public class WaveView extends View implements ValueAnimator.AnimatorUpdateListen
             case MotionEvent.ACTION_DOWN:
                 removeCallbacks(mLockTimerActions);
                 mFingerDown = true;
-                setGrabbedState(OnTriggerListener.CENTER_HANDLE);
-                {
-                    float x = mMouseX - mUnlockHalo.getX();
-                    float y = mMouseY - mUnlockHalo.getY();
-                    float dist = (float) Math.hypot(x, y);
-                    if (dist < mUnlockHalo.getWidth()*0.5f) {
-                        if (mLockState == STATE_READY) {
-                            mLockState = STATE_START_ATTEMPT;
-                        }
-                    }
-                }
+                tryTransitionToStartAttemptState(event);
                 handled = true;
                 break;
 
             case MotionEvent.ACTION_MOVE:
+                tryTransitionToStartAttemptState(event);
                 handled = true;
                 break;
 
@@ -501,6 +528,47 @@ public class WaveView extends View implements ValueAnimator.AnimatorUpdateListen
         return handled ? true : super.onTouchEvent(event);
     }
 
+    /**
+     * Tries to transition to start attempt state.
+     *
+     * @param event A motion event.
+     */
+    private void tryTransitionToStartAttemptState(MotionEvent event) {
+        final float dx = event.getX() - mUnlockHalo.getX();
+        final float dy = event.getY() - mUnlockHalo.getY();
+        float dist = (float) Math.hypot(dx, dy);
+        if (dist <= getScaledGrabHandleRadius()) {
+            setGrabbedState(OnTriggerListener.CENTER_HANDLE);
+            if (mLockState == STATE_READY) {
+                mLockState = STATE_START_ATTEMPT;
+                if (AccessibilityManager.getInstance(mContext).isEnabled()) {
+                    announceUnlockHandle();
+                }
+            }
+        }
+    }
+
+    /**
+     * @return The radius in which the handle is grabbed scaled based on
+     *     whether accessibility is enabled.
+     */
+    private float getScaledGrabHandleRadius() {
+        if (AccessibilityManager.getInstance(mContext).isEnabled()) {
+            return GRAB_HANDLE_RADIUS_SCALE_ACCESSIBILITY_ENABLED * mUnlockHalo.getWidth();
+        } else {
+            return GRAB_HANDLE_RADIUS_SCALE_ACCESSIBILITY_DISABLED * mUnlockHalo.getWidth();
+        }
+    }
+
+    /**
+     * Announces the unlock handle if accessibility is enabled.
+     */
+    private void announceUnlockHandle() {
+        setContentDescription(mContext.getString(R.string.description_target_unlock_tablet));
+        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
+        setContentDescription(null);
+    }
+
     /**
      * Triggers haptic feedback.
      */
diff --git a/core/res/res/values/strings.xml b/core/res/res/values/strings.xml
index fb4783b518024..a819173421805 100755
--- a/core/res/res/values/strings.xml
+++ b/core/res/res/values/strings.xml
@@ -3248,6 +3248,9 @@
     <!-- Description of the sound on target in the Slide unlock screen. [CHAR LIMIT=NONE] -->
     <string name="description_target_soundon">Sound on</string>
 
+    <!-- Description of the unlock handle in the Slide unlock screen for tablets. [CHAR LIMIT=NONE] -->
+    <string name="description_target_unlock_tablet">Swipe to unlock.</string>
+
     <!-- Announce that a headset is required to hear keyboard keys while typing a password. [CHAR LIMIT=NONE] -->
     <string name="keyboard_headset_required_to_hear_password">Plug in a headset to hear password keys spoken aloud.</string>
     <!-- The value of a keyboard key announced when accessibility is enabled and no headsed is used. [CHAR LIMIT=NONE] -->