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 
17 package androidx.wear.ble.view;
18 
19 import android.animation.ObjectAnimator;
20 import android.animation.TimeInterpolator;
21 import android.animation.ValueAnimator;
22 import android.annotation.TargetApi;
23 import android.graphics.Canvas;
24 import android.graphics.ColorFilter;
25 import android.graphics.Paint;
26 import android.graphics.PixelFormat;
27 import android.graphics.RectF;
28 import android.graphics.drawable.Drawable;
29 import android.os.Build;
30 import android.util.Property;
31 import android.view.animation.LinearInterpolator;
32 
33 /**
34  * Drawable for showing an indeterminate progress indicator.
35  *
36  * TODO: When Material progress drawable is available in the support library stop using this.
37  *
38  * @hide
39  */
40 @TargetApi(Build.VERSION_CODES.KITKAT_WATCH)
41 class ProgressDrawable extends Drawable {
42 
43     private static Property<ProgressDrawable, Integer> LEVEL =
44             new Property<ProgressDrawable, Integer>(Integer.class, "level") {
45         @Override
46         public Integer get(ProgressDrawable drawable) {
47             return drawable.getLevel();
48         }
49 
50         @Override
51         public void set(ProgressDrawable drawable, Integer value) {
52             drawable.setLevel(value);
53             drawable.invalidateSelf();
54         }
55     };
56     /** Max level for a level drawable, as specified in developer docs for {@link Drawable}. */
57     private static final int MAX_LEVEL = 10000;
58 
59     /** How many different sections are there, five gives us the material style star. **/
60     private static final int NUMBER_OF_SEGMENTS = 5;
61 
62     private static final int LEVELS_PER_SEGMENT = MAX_LEVEL / NUMBER_OF_SEGMENTS;
63     private static final float STARTING_ANGLE = -90f;
64     private static final long ANIMATION_DURATION = 6000;
65     private static final int FULL_CIRCLE = 360;
66     private static final int MAX_SWEEP = 306;
67     private static final int CORRECTION_ANGLE = FULL_CIRCLE - MAX_SWEEP;
68     /** How far through each cycle does the bar stop growing and start shrinking, half way. **/
69     private static final float GROW_SHRINK_RATIO = 0.5f;
70     // TODO: replace this with BakedBezierInterpolator when its available in support library.
71     private static final TimeInterpolator mInterpolator = Gusterpolator.INSTANCE;
72 
73     private final RectF mInnerCircleBounds = new RectF();
74     private final Paint mPaint = new Paint();
75     private final ObjectAnimator mAnimator;
76     private float mCircleBorderWidth;
77     private int mCircleBorderColor;
78 
ProgressDrawable()79     public ProgressDrawable() {
80         mPaint.setAntiAlias(true);
81         mPaint.setStyle(Paint.Style.STROKE);
82         mAnimator = ObjectAnimator.ofInt(this, LEVEL, 0, MAX_LEVEL);
83         mAnimator.setRepeatCount(ValueAnimator.INFINITE);
84         mAnimator.setRepeatMode(ValueAnimator.RESTART);
85         mAnimator.setDuration(ANIMATION_DURATION);
86         mAnimator.setInterpolator(new LinearInterpolator());
87     }
88 
setRingColor(int color)89     public void setRingColor(int color) {
90         mCircleBorderColor = color;
91     }
92 
setRingWidth(float width)93     public void setRingWidth(float width) {
94         mCircleBorderWidth = width;
95     }
96 
startAnimation()97     public void startAnimation() {
98         mAnimator.start();
99     }
100 
stopAnimation()101     public void stopAnimation() {
102         mAnimator.cancel();
103     }
104 
105     @Override
draw(Canvas canvas)106     public void draw(Canvas canvas) {
107         canvas.save();
108         mInnerCircleBounds.set(getBounds());
109         mInnerCircleBounds.inset(mCircleBorderWidth / 2.0f, mCircleBorderWidth / 2.0f);
110         mPaint.setStrokeWidth(mCircleBorderWidth);
111         mPaint.setColor(mCircleBorderColor);
112 
113         float sweepAngle = FULL_CIRCLE;
114         boolean growing = false;
115         float correctionAngle = 0;
116         int level = getLevel();
117 
118         int currentSegment = level / LEVELS_PER_SEGMENT;
119         int offset = currentSegment * LEVELS_PER_SEGMENT;
120         float progress = (level - offset) / (float) LEVELS_PER_SEGMENT;
121 
122         growing = progress < GROW_SHRINK_RATIO;
123         correctionAngle = CORRECTION_ANGLE * progress;
124 
125         if (growing) {
126             sweepAngle = MAX_SWEEP * mInterpolator.getInterpolation(
127                     lerpInv(0f, GROW_SHRINK_RATIO, progress));
128         } else {
129             sweepAngle = MAX_SWEEP * (1.0f - mInterpolator.getInterpolation(
130                     lerpInv(GROW_SHRINK_RATIO, 1.0f, progress)));
131         }
132 
133         sweepAngle = Math.max(1, sweepAngle);
134 
135         canvas.rotate(
136                 level * (1.0f / MAX_LEVEL) * 2 * FULL_CIRCLE + STARTING_ANGLE + correctionAngle,
137                 mInnerCircleBounds.centerX(),
138                 mInnerCircleBounds.centerY());
139         canvas.drawArc(mInnerCircleBounds,
140                 growing ? 0 : MAX_SWEEP - sweepAngle,
141                 sweepAngle,
142                 false,
143                 mPaint);
144         canvas.restore();
145     }
146 
147     @Override
148     public void setAlpha(int i) {
149         // Not supported.
150     }
151 
152     @Override
153     public void setColorFilter(ColorFilter colorFilter) {
154         // Not supported.
155     }
156 
157     @Override
158     public int getOpacity() {
159         return PixelFormat.OPAQUE;
160     }
161 
162     @Override
163     protected boolean onLevelChange(int level) {
164         return true; // Changing the level of this drawable does change its appearance.
165     }
166 
167     /**
168      * Returns the interpolation scalar (s) that satisfies the equation:
169      * {@code value = }lerp(a, b, s)
170      *
171      * <p>If {@code a == b}, then this function will return 0.
172      */
173     private static float lerpInv(float a, float b, float value) {
174         return a != b ? ((value - a) / (b - a)) : 0.0f;
175     }
176 }
177