1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.launcher3;
17 
18 import android.animation.Animator;
19 import android.animation.ObjectAnimator;
20 import android.content.res.Resources;
21 import android.graphics.Canvas;
22 import android.graphics.Color;
23 import android.graphics.Paint;
24 import android.graphics.Rect;
25 import android.graphics.drawable.Drawable;
26 
27 /**
28  * The fast scroller popup that shows the section name the list will jump to.
29  */
30 public class BaseRecyclerViewFastScrollPopup {
31 
32     private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;
33 
34     private Resources mRes;
35     private BaseRecyclerView mRv;
36 
37     private Drawable mBg;
38     // The absolute bounds of the fast scroller bg
39     private Rect mBgBounds = new Rect();
40     private int mBgOriginalSize;
41     private Rect mInvalidateRect = new Rect();
42     private Rect mTmpRect = new Rect();
43 
44     private String mSectionName;
45     private Paint mTextPaint;
46     private Rect mTextBounds = new Rect();
47     private float mAlpha;
48 
49     private Animator mAlphaAnimator;
50     private boolean mVisible;
51 
BaseRecyclerViewFastScrollPopup(BaseRecyclerView rv, Resources res)52     public BaseRecyclerViewFastScrollPopup(BaseRecyclerView rv, Resources res) {
53         mRes = res;
54         mRv = rv;
55         mBgOriginalSize = res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_size);
56         mBg = res.getDrawable(R.drawable.container_fastscroll_popup_bg);
57         mBg.setBounds(0, 0, mBgOriginalSize, mBgOriginalSize);
58         mTextPaint = new Paint();
59         mTextPaint.setColor(Color.WHITE);
60         mTextPaint.setAntiAlias(true);
61         mTextPaint.setTextSize(res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_text_size));
62     }
63 
64     /**
65      * Sets the section name.
66      */
setSectionName(String sectionName)67     public void setSectionName(String sectionName) {
68         if (!sectionName.equals(mSectionName)) {
69             mSectionName = sectionName;
70             mTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTextBounds);
71             // Update the width to use measureText since that is more accurate
72             mTextBounds.right = (int) (mTextBounds.left + mTextPaint.measureText(sectionName));
73         }
74     }
75 
76     /**
77      * Updates the bounds for the fast scroller.
78      * @return the invalidation rect for this update.
79      */
updateFastScrollerBounds(int lastTouchY)80     public Rect updateFastScrollerBounds(int lastTouchY) {
81         mInvalidateRect.set(mBgBounds);
82 
83         if (isVisible()) {
84             // Calculate the dimensions and position of the fast scroller popup
85             int edgePadding = mRv.getMaxScrollbarWidth();
86             int bgPadding = (mBgOriginalSize - mTextBounds.height()) / 2;
87             int bgHeight = mBgOriginalSize;
88             int bgWidth = Math.max(mBgOriginalSize, mTextBounds.width() + (2 * bgPadding));
89             if (Utilities.isRtl(mRes)) {
90                 mBgBounds.left = mRv.getBackgroundPadding().left + (2 * mRv.getMaxScrollbarWidth());
91                 mBgBounds.right = mBgBounds.left + bgWidth;
92             } else {
93                 mBgBounds.right = mRv.getWidth() - mRv.getBackgroundPadding().right -
94                         (2 * mRv.getMaxScrollbarWidth());
95                 mBgBounds.left = mBgBounds.right - bgWidth;
96             }
97             mBgBounds.top = lastTouchY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgHeight);
98             mBgBounds.top = Math.max(edgePadding,
99                     Math.min(mBgBounds.top, mRv.getHeight() - edgePadding - bgHeight));
100             mBgBounds.bottom = mBgBounds.top + bgHeight;
101         } else {
102             mBgBounds.setEmpty();
103         }
104 
105         // Combine the old and new fast scroller bounds to create the full invalidate rect
106         mInvalidateRect.union(mBgBounds);
107         return mInvalidateRect;
108     }
109 
110     /**
111      * Animates the visibility of the fast scroller popup.
112      */
animateVisibility(boolean visible)113     public void animateVisibility(boolean visible) {
114         if (mVisible != visible) {
115             mVisible = visible;
116             if (mAlphaAnimator != null) {
117                 mAlphaAnimator.cancel();
118             }
119             mAlphaAnimator = ObjectAnimator.ofFloat(this, "alpha", visible ? 1f : 0f);
120             mAlphaAnimator.setDuration(visible ? 200 : 150);
121             mAlphaAnimator.start();
122         }
123     }
124 
125     // Setter/getter for the popup alpha for animations
setAlpha(float alpha)126     public void setAlpha(float alpha) {
127         mAlpha = alpha;
128         mRv.invalidate(mBgBounds);
129     }
130 
getAlpha()131     public float getAlpha() {
132         return mAlpha;
133     }
134 
getHeight()135     public int getHeight() {
136         return mBgOriginalSize;
137     }
138 
draw(Canvas c)139     public void draw(Canvas c) {
140         if (isVisible()) {
141             // Draw the fast scroller popup
142             int restoreCount = c.save(Canvas.MATRIX_SAVE_FLAG);
143             c.translate(mBgBounds.left, mBgBounds.top);
144             mTmpRect.set(mBgBounds);
145             mTmpRect.offsetTo(0, 0);
146             mBg.setBounds(mTmpRect);
147             mBg.setAlpha((int) (mAlpha * 255));
148             mBg.draw(c);
149             mTextPaint.setAlpha((int) (mAlpha * 255));
150             c.drawText(mSectionName, (mBgBounds.width() - mTextBounds.width()) / 2,
151                     mBgBounds.height() - (mBgBounds.height() - mTextBounds.height()) / 2,
152                     mTextPaint);
153             c.restoreToCount(restoreCount);
154         }
155     }
156 
isVisible()157     public boolean isVisible() {
158         return (mAlpha > 0f) && (mSectionName != null);
159     }
160 }
161