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      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 android.support.wearable.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 
     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 
     89     public void setRingColor(int color) {
     90         mCircleBorderColor = color;
     91     }
     92 
     93     public void setRingWidth(float width) {
     94         mCircleBorderWidth = width;
     95     }
     96 
     97     public void startAnimation() {
     98         mAnimator.start();
     99     }
    100 
    101     public void stopAnimation() {
    102         mAnimator.cancel();
    103     }
    104 
    105     @Override
    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