Improve DatePicker focus for keyboards.

Bug 24873983

Focus moves properly within the SimpleMonthView and between
components of the DatePicker.

Change-Id: I61778f9b4f19536ff6c7a512f9b4faf7bf4447a7

1 files changed, 247 insertions, 6 deletions

diff --git a/core/java/android/widget/SimpleMonthView.java b/core/java/android/widget/SimpleMonthView.java
index e9325efcea09..6edce91db504 100644
--- a/core/java/android/widget/SimpleMonthView.java
+++ b/core/java/android/widget/SimpleMonthView.java
@@ -16,6 +16,7 @@
 
 package android.widget;
 
+import android.annotation.Nullable;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.Resources;
@@ -34,8 +35,10 @@ import android.util.AttributeSet;
 import android.util.IntArray;
 import android.util.MathUtils;
 import android.util.StateSet;
+import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.ViewParent;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
@@ -61,11 +64,14 @@ class SimpleMonthView extends View {
     private static final String DEFAULT_TITLE_FORMAT = "MMMMy";
     private static final String DAY_OF_WEEK_FORMAT = "EEEEE";
 
+    private static final int SELECTED_HIGHLIGHT_ALPHA = 0xB0;
+
     private final TextPaint mMonthPaint = new TextPaint();
     private final TextPaint mDayOfWeekPaint = new TextPaint();
     private final TextPaint mDayPaint = new TextPaint();
     private final Paint mDaySelectorPaint = new Paint();
     private final Paint mDayHighlightPaint = new Paint();
+    private final Paint mDayHighlightSelectorPaint = new Paint();
 
     private final Calendar mCalendar = Calendar.getInstance();
     private final Calendar mDayOfWeekLabelCalendar = Calendar.getInstance();
@@ -130,7 +136,9 @@ class SimpleMonthView extends View {
 
     private ColorStateList mDayTextColor;
 
-    private int mTouchedItem = -1;
+    private int mHighlightedDay = -1;
+    private int mPreviouslyHighlightedDay = -1;
+    private boolean mIsTouchHighlighted = false;
 
     public SimpleMonthView(Context context) {
         this(context, null);
@@ -268,6 +276,9 @@ class SimpleMonthView extends View {
         mDayHighlightPaint.setAntiAlias(true);
         mDayHighlightPaint.setStyle(Style.FILL);
 
+        mDayHighlightSelectorPaint.setAntiAlias(true);
+        mDayHighlightSelectorPaint.setStyle(Style.FILL);
+
         mDayPaint.setAntiAlias(true);
         mDayPaint.setTextSize(dayTextSize);
         mDayPaint.setTypeface(Typeface.create(dayTypeface, 0));
@@ -296,6 +307,8 @@ class SimpleMonthView extends View {
         final int activatedColor = dayBackgroundColor.getColorForState(
                 StateSet.get(StateSet.VIEW_STATE_ENABLED | StateSet.VIEW_STATE_ACTIVATED), 0);
         mDaySelectorPaint.setColor(activatedColor);
+        mDayHighlightSelectorPaint.setColor(activatedColor);
+        mDayHighlightSelectorPaint.setAlpha(SELECTED_HIGHLIGHT_ALPHA);
         invalidate();
     }
 
@@ -326,8 +339,10 @@ class SimpleMonthView extends View {
             case MotionEvent.ACTION_DOWN:
             case MotionEvent.ACTION_MOVE:
                 final int touchedItem = getDayAtLocation(x, y);
-                if (mTouchedItem != touchedItem) {
-                    mTouchedItem = touchedItem;
+                mIsTouchHighlighted = true;
+                if (mHighlightedDay != touchedItem) {
+                    mHighlightedDay = touchedItem;
+                    mPreviouslyHighlightedDay = touchedItem;
                     invalidate();
                 }
                 if (action == MotionEvent.ACTION_DOWN && touchedItem < 0) {
@@ -342,7 +357,8 @@ class SimpleMonthView extends View {
                 // Fall through.
             case MotionEvent.ACTION_CANCEL:
                 // Reset touched day on stream end.
-                mTouchedItem = -1;
+                mHighlightedDay = -1;
+                mIsTouchHighlighted = false;
                 invalidate();
                 break;
         }
@@ -350,6 +366,228 @@ class SimpleMonthView extends View {
     }
 
     @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        // We need to handle focus change within the SimpleMonthView because we are simulating
+        // multiple Views. The arrow keys will move between days until there is no space (no
+        // day to the left, top, right, or bottom). Focus forward and back jumps out of the
+        // SimpleMonthView, skipping over other SimpleMonthViews in the parent ViewPager
+        // to the next focusable View in the hierarchy.
+        boolean focusChanged = false;
+        switch (event.getKeyCode()) {
+            case KeyEvent.KEYCODE_DPAD_LEFT:
+                if (event.hasNoModifiers()) {
+                    focusChanged = moveOneDay(isLayoutRtl());
+                }
+                break;
+            case KeyEvent.KEYCODE_DPAD_RIGHT:
+                if (event.hasNoModifiers()) {
+                    focusChanged = moveOneDay(!isLayoutRtl());
+                }
+                break;
+            case KeyEvent.KEYCODE_DPAD_UP:
+                if (event.hasNoModifiers()) {
+                    ensureFocusedDay();
+                    if (mHighlightedDay > 7) {
+                        mHighlightedDay -= 7;
+                        focusChanged = true;
+                    }
+                }
+                break;
+            case KeyEvent.KEYCODE_DPAD_DOWN:
+                if (event.hasNoModifiers()) {
+                    ensureFocusedDay();
+                    if (mHighlightedDay <= mDaysInMonth - 7) {
+                        mHighlightedDay += 7;
+                        focusChanged = true;
+                    }
+                }
+                break;
+            case KeyEvent.KEYCODE_DPAD_CENTER:
+            case KeyEvent.KEYCODE_ENTER:
+                if (mHighlightedDay != -1) {
+                    onDayClicked(mHighlightedDay);
+                    return true;
+                }
+                break;
+            case KeyEvent.KEYCODE_TAB: {
+                int focusChangeDirection = 0;
+                if (event.hasNoModifiers()) {
+                    focusChangeDirection = View.FOCUS_FORWARD;
+                } else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) {
+                    focusChangeDirection = View.FOCUS_BACKWARD;
+                }
+                if (focusChangeDirection != 0) {
+                    final ViewParent parent = getParent();
+                    // move out of the ViewPager next/previous
+                    View nextFocus = this;
+                    do {
+                        nextFocus = nextFocus.focusSearch(focusChangeDirection);
+                    } while (nextFocus != null && nextFocus != this &&
+                            nextFocus.getParent() == parent);
+                    if (nextFocus != null) {
+                        nextFocus.requestFocus();
+                        return true;
+                    }
+                }
+                break;
+            }
+        }
+        if (focusChanged) {
+            invalidate();
+            return true;
+        } else {
+            return super.onKeyDown(keyCode, event);
+        }
+    }
+
+    private boolean moveOneDay(boolean positive) {
+        ensureFocusedDay();
+        boolean focusChanged = false;
+        if (positive) {
+            if (!isLastDayOfWeek(mHighlightedDay) && mHighlightedDay < mDaysInMonth) {
+                mHighlightedDay++;
+                focusChanged = true;
+            }
+        } else {
+            if (!isFirstDayOfWeek(mHighlightedDay) && mHighlightedDay > 1) {
+                mHighlightedDay--;
+                focusChanged = true;
+            }
+        }
+        return focusChanged;
+    }
+
+    @Override
+    protected void onFocusChanged(boolean gainFocus, @FocusDirection int direction,
+            @Nullable Rect previouslyFocusedRect) {
+        if (gainFocus) {
+            // If we've gained focus through arrow keys, we should find the day closest
+            // to the focus rect. If we've gained focus through forward/back, we should
+            // focus on the selected day if there is one.
+            final int offset = findDayOffset();
+            switch(direction) {
+                case View.FOCUS_RIGHT: {
+                    int row = findClosestRow(previouslyFocusedRect);
+                    mHighlightedDay = row == 0 ? 1 : (row * DAYS_IN_WEEK) - offset + 1;
+                    break;
+                }
+                case View.FOCUS_LEFT: {
+                    int row = findClosestRow(previouslyFocusedRect) + 1;
+                    mHighlightedDay = Math.min(mDaysInMonth, (row * DAYS_IN_WEEK) - offset);
+                    break;
+                }
+                case View.FOCUS_DOWN: {
+                    final int col = findClosestColumn(previouslyFocusedRect);
+                    final int day = col - offset + 1;
+                    mHighlightedDay = day < 1 ? day + DAYS_IN_WEEK : day;
+                    break;
+                }
+                case View.FOCUS_UP: {
+                    final int col = findClosestColumn(previouslyFocusedRect);
+                    final int maxWeeks = (offset + mDaysInMonth) / DAYS_IN_WEEK;
+                    final int day = col - offset + (DAYS_IN_WEEK * maxWeeks) + 1;
+                    mHighlightedDay = day > mDaysInMonth ? day - DAYS_IN_WEEK : day;
+                    break;
+                }
+            }
+            ensureFocusedDay();
+            invalidate();
+        }
+        super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
+    }
+
+    /**
+     * Returns the row (0 indexed) closest to previouslyFocusedRect or center if null.
+     */
+    private int findClosestRow(@Nullable Rect previouslyFocusedRect) {
+        if (previouslyFocusedRect == null) {
+            return 3;
+        } else {
+            int centerY = previouslyFocusedRect.centerY();
+
+            final TextPaint p = mDayPaint;
+            final int headerHeight = mMonthHeight + mDayOfWeekHeight;
+            final int rowHeight = mDayHeight;
+
+            // Text is vertically centered within the row height.
+            final float halfLineHeight = (p.ascent() + p.descent()) / 2f;
+            final int rowCenter = headerHeight + rowHeight / 2;
+
+            centerY -= rowCenter - halfLineHeight;
+            int row = Math.round(centerY / (float) rowHeight);
+            final int maxDay = findDayOffset() + mDaysInMonth;
+            final int maxRows = (maxDay / DAYS_IN_WEEK) - ((maxDay % DAYS_IN_WEEK == 0) ? 1 : 0);
+
+            row = MathUtils.constrain(row, 0, maxRows);
+            return row;
+        }
+    }
+
+    /**
+     * Returns the column (0 indexed) closest to the previouslyFocusedRect or center if null.
+     * The 0 index is related to the first day of the week.
+     */
+    private int findClosestColumn(@Nullable Rect previouslyFocusedRect) {
+        if (previouslyFocusedRect == null) {
+            return DAYS_IN_WEEK / 2;
+        } else {
+            int centerX = previouslyFocusedRect.centerX() - mPaddingLeft;
+            final int columnFromLeft =
+                    MathUtils.constrain(centerX / mCellWidth, 0, DAYS_IN_WEEK - 1);
+            return isLayoutRtl() ? DAYS_IN_WEEK - columnFromLeft - 1: columnFromLeft;
+        }
+    }
+
+    @Override
+    public void getFocusedRect(Rect r) {
+        if (mHighlightedDay > 0) {
+            getBoundsForDay(mHighlightedDay, r);
+        } else {
+            super.getFocusedRect(r);
+        }
+    }
+
+    @Override
+    protected void onFocusLost() {
+        if (!mIsTouchHighlighted) {
+            // Unhighlight a day.
+            mPreviouslyHighlightedDay = mHighlightedDay;
+            mHighlightedDay = -1;
+            invalidate();
+        }
+        super.onFocusLost();
+    }
+
+    /**
+     * Ensure some day is highlighted. If a day isn't highlighted, it chooses the selected day,
+     * if possible, or the first day of the month if not.
+     */
+    private void ensureFocusedDay() {
+        if (mHighlightedDay != -1) {
+            return;
+        }
+        if (mPreviouslyHighlightedDay != -1) {
+            mHighlightedDay = mPreviouslyHighlightedDay;
+            return;
+        }
+        if (mActivatedDay != -1) {
+            mHighlightedDay = mActivatedDay;
+            return;
+        }
+        mHighlightedDay = 1;
+    }
+
+    private boolean isFirstDayOfWeek(int day) {
+        final int offset = findDayOffset();
+        return (offset + day - 1) % DAYS_IN_WEEK == 0;
+    }
+
+    private boolean isLastDayOfWeek(int day) {
+        final int offset = findDayOffset();
+        return (offset + day) % DAYS_IN_WEEK == 0;
+    }
+
+    @Override
     protected void onDraw(Canvas canvas) {
         final int paddingLeft = getPaddingLeft();
         final int paddingTop = getPaddingTop();
@@ -432,12 +670,15 @@ class SimpleMonthView extends View {
             }
 
             final boolean isDayActivated = mActivatedDay == day;
+            final boolean isDayHighlighted = mHighlightedDay == day;
             if (isDayActivated) {
                 stateMask |= StateSet.VIEW_STATE_ACTIVATED;
 
                 // Adjust the circle to be centered on the row.
-                canvas.drawCircle(colCenterRtl, rowCenter, mDaySelectorRadius, mDaySelectorPaint);
-            } else if (mTouchedItem == day) {
+                final Paint paint = isDayHighlighted ? mDayHighlightSelectorPaint :
+                        mDaySelectorPaint;
+                canvas.drawCircle(colCenterRtl, rowCenter, mDaySelectorRadius, paint);
+            } else if (isDayHighlighted) {
                 stateMask |= StateSet.VIEW_STATE_PRESSED;
 
                 if (isDayEnabled) {