summaryrefslogtreecommitdiffstats
path: root/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java
blob: 2c4184dc48d74867cac430dc0846eb32cfaa6e58 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.launcher3;

import android.animation.AnimatorSet;
import android.animation.ArgbEvaluator;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.view.MotionEvent;
import android.view.ViewConfiguration;

import com.android.launcher3.util.Thunk;

/**
 * The track and scrollbar that shows when you scroll the list.
 */
public class BaseRecyclerViewFastScrollBar {

    public interface FastScrollFocusableView {
        void setFastScrollFocused(boolean focused, boolean animated);
    }

    private final static int MAX_TRACK_ALPHA = 30;
    private final static int SCROLL_BAR_VIS_DURATION = 150;

    @Thunk BaseRecyclerView mRv;
    private BaseRecyclerViewFastScrollPopup mPopup;

    private AnimatorSet mScrollbarAnimator;

    private int mThumbInactiveColor;
    private int mThumbActiveColor;
    @Thunk Point mThumbOffset = new Point(-1, -1);
    @Thunk Paint mThumbPaint;
    private Paint mTrackPaint;
    private int mThumbMinWidth;
    private int mThumbMaxWidth;
    @Thunk int mThumbWidth;
    @Thunk int mThumbHeight;
    // The inset is the buffer around which a point will still register as a click on the scrollbar
    private int mTouchInset;
    private boolean mIsDragging;

    // This is the offset from the top of the scrollbar when the user first starts touching.  To
    // prevent jumping, this offset is applied as the user scrolls.
    private int mTouchOffset;

    private Rect mInvalidateRect = new Rect();
    private Rect mTmpRect = new Rect();

    public BaseRecyclerViewFastScrollBar(BaseRecyclerView rv, Resources res) {
        mRv = rv;
        mPopup = new BaseRecyclerViewFastScrollPopup(rv, res);
        mTrackPaint = new Paint();
        mTrackPaint.setColor(rv.getFastScrollerTrackColor(Color.BLACK));
        mTrackPaint.setAlpha(0);
        mThumbInactiveColor = rv.getFastScrollerThumbInactiveColor(
                res.getColor(R.color.container_fastscroll_thumb_inactive_color));
        mThumbActiveColor = res.getColor(R.color.container_fastscroll_thumb_active_color);
        mThumbPaint = new Paint();
        mThumbPaint.setColor(mThumbInactiveColor);
        mThumbWidth = mThumbMinWidth = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_min_width);
        mThumbMaxWidth = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_max_width);
        mThumbHeight = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_height);
        mTouchInset = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_touch_inset);
    }

    public void setScrollbarThumbOffset(int x, int y) {
        if (mThumbOffset.x == x && mThumbOffset.y == y) {
            return;
        }
        mInvalidateRect.set(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth, mRv.getHeight());
        mThumbOffset.set(x, y);
        mInvalidateRect.union(new Rect(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth,
                mRv.getHeight()));
        mRv.invalidate(mInvalidateRect);
    }

    // Setter/getter for the search bar width for animations
    public void setWidth(int width) {
        mInvalidateRect.set(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth, mRv.getHeight());
        mThumbWidth = width;
        mInvalidateRect.union(new Rect(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth,
                mRv.getHeight()));
        mRv.invalidate(mInvalidateRect);
    }

    public int getWidth() {
        return mThumbWidth;
    }

    // Setter/getter for the track background alpha for animations
    public void setTrackAlpha(int alpha) {
        mTrackPaint.setAlpha(alpha);
        mInvalidateRect.set(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth, mRv.getHeight());
        mRv.invalidate(mInvalidateRect);
    }

    public int getTrackAlpha() {
        return mTrackPaint.getAlpha();
    }

    public int getThumbHeight() {
        return mThumbHeight;
    }

    public int getThumbMaxWidth() {
        return mThumbMaxWidth;
    }

    public boolean isDragging() {
        return mIsDragging;
    }

    /**
     * Handles the touch event and determines whether to show the fast scroller (or updates it if
     * it is already showing).
     */
    public void handleTouchEvent(MotionEvent ev, int downX, int downY, int lastY) {
        ViewConfiguration config = ViewConfiguration.get(mRv.getContext());

        int action = ev.getAction();
        int y = (int) ev.getY();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                if (isNearPoint(downX, downY)) {
                    mTouchOffset = downY - mThumbOffset.y;
                }
                break;
            case MotionEvent.ACTION_MOVE:
                // Check if we should start scrolling
                if (!mIsDragging && isNearPoint(downX, downY) &&
                        Math.abs(y - downY) > config.getScaledTouchSlop()) {
                    mRv.getParent().requestDisallowInterceptTouchEvent(true);
                    mIsDragging = true;
                    mTouchOffset += (lastY - downY);
                    mPopup.animateVisibility(true);
                    animateScrollbar(true);
                }
                if (mIsDragging) {
                    // Update the fastscroller section name at this touch position
                    int top = mRv.getBackgroundPadding().top;
                    int bottom = mRv.getHeight() - mRv.getBackgroundPadding().bottom - mThumbHeight;
                    float boundedY = (float) Math.max(top, Math.min(bottom, y - mTouchOffset));
                    String sectionName = mRv.scrollToPositionAtProgress((boundedY - top) /
                            (bottom - top));
                    mPopup.setSectionName(sectionName);
                    mPopup.animateVisibility(!sectionName.isEmpty());
                    mRv.invalidate(mPopup.updateFastScrollerBounds(mRv, lastY));
                }
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                mTouchOffset = 0;
                if (mIsDragging) {
                    mIsDragging = false;
                    mPopup.animateVisibility(false);
                    animateScrollbar(false);
                }
                break;
        }
    }

    public void draw(Canvas canvas) {
        if (mThumbOffset.x < 0 || mThumbOffset.y < 0) {
            return;
        }

        // Draw the scroll bar track and thumb
        if (mTrackPaint.getAlpha() > 0) {
            canvas.drawRect(mThumbOffset.x, 0, mThumbOffset.x + mThumbWidth, mRv.getHeight(), mTrackPaint);
        }
        canvas.drawRect(mThumbOffset.x, mThumbOffset.y, mThumbOffset.x + mThumbWidth,
                mThumbOffset.y + mThumbHeight, mThumbPaint);

        // Draw the popup
        mPopup.draw(canvas);
    }

    /**
     * Animates the width and color of the scrollbar.
     */
    private void animateScrollbar(boolean isScrolling) {
        if (mScrollbarAnimator != null) {
            mScrollbarAnimator.cancel();
        }
        ObjectAnimator trackAlphaAnim = ObjectAnimator.ofInt(this, "trackAlpha",
                isScrolling ? MAX_TRACK_ALPHA : 0);
        ObjectAnimator thumbWidthAnim = ObjectAnimator.ofInt(this, "width",
                isScrolling ? mThumbMaxWidth : mThumbMinWidth);
        ValueAnimator colorAnimation = ValueAnimator.ofObject(new ArgbEvaluator(),
                mThumbPaint.getColor(), isScrolling ? mThumbActiveColor : mThumbInactiveColor);
        colorAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animator) {
                mThumbPaint.setColor((Integer) animator.getAnimatedValue());
                mRv.invalidate(mThumbOffset.x, mThumbOffset.y, mThumbOffset.x + mThumbWidth,
                        mThumbOffset.y + mThumbHeight);
            }
        });
        mScrollbarAnimator = new AnimatorSet();
        mScrollbarAnimator.playTogether(trackAlphaAnim, thumbWidthAnim, colorAnimation);
        mScrollbarAnimator.setDuration(SCROLL_BAR_VIS_DURATION);
        mScrollbarAnimator.start();
    }

    /**
     * Returns whether the specified points are near the scroll bar bounds.
     */
    private boolean isNearPoint(int x, int y) {
        mTmpRect.set(mThumbOffset.x, mThumbOffset.y, mThumbOffset.x + mThumbWidth,
                mThumbOffset.y + mThumbHeight);
        mTmpRect.inset(mTouchInset, mTouchInset);
        return mTmpRect.contains(x, y);
    }
}