1 import android.annotation.TargetApi;  2 import android.content.Context;  3 import android.content.res.Resources;  4 import android.content.res.TypedArray;  5 import android.graphics.Canvas;  6 import android.graphics.Paint;  7 import android.graphics.RectF;  8 import android.os.Build;  9 import android.util.AttributeSet; 10 import android.view.View; 11  12 /** 13  * 类似螺纹的加载view 14  * 可以自定义的属性：颜色、旋转速度（X弧度/s） 15  */ 16 public class WhorlView extends View { 17     private static final int CIRCLE_NUM = 3; 18  19     public static final int FAST = 1; 20     public static final int MEDIUM = 0; 21     public static final int SLOW = 2; 22  23     private static final int PARALLAX_FAST = 60; 24     private static final int PARALLAX_MEDIUM = 72; 25     private static final int PARALLAX_SLOW = 90; 26  27     private static final float SWEEP_ANGLE = 90f; 28     private static final float STOKE_WIDTH = 5f; 29     private static final long REFRESH_DURATION = 16L; 30  31     private long mCircleTime; 32     private int[] mLayerColors = new int[CIRCLE_NUM]; 33     private int mCircleSpeed; 34     private int mParallaxSpeed; 35  36     public WhorlView(Context context) { 37         this(context, null, 0); 38     } 39  40     public WhorlView(Context context, AttributeSet attrs) { 41         this(context, attrs, 0); 42     } 43  44     public WhorlView(Context context, AttributeSet attrs, int defStyleAttr) { 45         super(context, attrs, defStyleAttr); 46         Resources res = getResources(); 47         final int defaultSmallColor = res.getColor(R.color.material_red); 48         final int defaultMiddleColor = res.getColor(R.color.material_green); 49         final int defaultBigColor = res.getColor(R.color.material_blue); 50         //默认外层最慢180度/s 51         final int defaultCircleSpeed = 270; 52         if (attrs != null) { 53             final TypedArray typedArray = context.obtainStyledAttributes( 54                     attrs, R.styleable.WhorlView_Style); 55          mLayerColors[0] = typedArray.getColor(R.styleable.WhorlView_Style_WhorlView_SmallWhorlColor, defaultSmallColor); 56             mLayerColors[1] = typedArray.getColor(R.styleable.WhorlView_Style_WhorlView_MiddleWhorlColor, defaultMiddleColor); 57             mLayerColors[2] = typedArray.getColor(R.styleable.WhorlView_Style_WhorlView_BigWhorlColor, defaultBigColor); 58             mCircleSpeed = typedArray.getInt(R.styleable.WhorlView_Style_WhorlView_CircleSpeed, defaultCircleSpeed); 59             int index = typedArray.getInt(R.styleable.WhorlView_Style_WhorlView_Parallax, 0); 60             setParallax(index); 61             typedArray.recycle(); 62         } else { 63             mLayerColors[0] = defaultSmallColor; 64             mLayerColors[1] = defaultMiddleColor; 65             mLayerColors[2] = defaultBigColor; 66             mCircleSpeed = defaultCircleSpeed; 67             mParallaxSpeed = PARALLAX_MEDIUM; 68         } 69     } 70  72     private void setParallax(int index) { 73         switch (index) { 74             case FAST: 75                 mParallaxSpeed = PARALLAX_FAST; 76                 break; 77             case MEDIUM: 78                 mParallaxSpeed = PARALLAX_MEDIUM; 79                 break; 80             case SLOW: 81                 mParallaxSpeed = PARALLAX_SLOW; 82                 break; 83             default: 84                 throw new IllegalStateException("no such parallax type"); 85         } 86     } 87  88     @Override 89     protected void onDraw(Canvas canvas) { 90         super.onDraw(canvas); 91         for (int i = 0; i < CIRCLE_NUM; i++) { 92             float angle = (mCircleSpeed + mParallaxSpeed * (CIRCLE_NUM - i - 1)) * mCircleTime * 0.001f; 93             drawArc(canvas, i, angle); 94         } 95     } 96  97     private boolean mIsCircling = false; 98  99     /**100      * 旋转开始 
     <功能简述>
      101      */102     public void start() {103         mIsCircling = true;104         new Thread(new Runnable() {105 106             @Override107             public void run() {108                 mCircleTime = 0L;109                 while (mIsCircling) {110                     invalidateWrap();111                     mCircleTime = mCircleTime + REFRESH_DURATION;112                     try {113                         Thread.sleep(REFRESH_DURATION);114                     } catch (InterruptedException e) {115                         e.printStackTrace();116                     }117                 }118             }119         }).start();120     }121 122     public void stop() {123         mIsCircling = false;124         mCircleTime = 0L;125         invalidateWrap();126     }127 128     public boolean isCircling(){129         return mIsCircling;130     }131 132     @TargetApi(Build.VERSION_CODES.JELLY_BEAN)133     private void invalidateWrap() {134         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {135             postInvalidateOnAnimation();136         } else {137             postInvalidate();138         }139     }140 141     /**142      * 画弧143      *144      * @param canvas145      * @param index      由内而外146      * @param startAngle147      */148     private void drawArc(Canvas canvas, int index, float startAngle) {149         Paint paint = checkArcPaint(index);150         //最大圆是view的边界151         RectF oval = checkRectF(calcuRadiusRatio(index));152         canvas.drawArc(oval, startAngle, SWEEP_ANGLE, false, paint);153     }154 155     private Paint mArcPaint;156 157     private Paint checkArcPaint(int index) {158         if (mArcPaint == null) {159             mArcPaint = new Paint();160         } else {161             mArcPaint.reset();162         }163         mArcPaint.setColor(mLayerColors[index]);164         mArcPaint.setStyle(Paint.Style.STROKE);165         mArcPaint.setStrokeWidth(STOKE_WIDTH);166         mArcPaint.setAntiAlias(true);167         return mArcPaint;168     }169 170     private RectF mOval;171 172     private RectF checkRectF(float radiusRatio) {173         if (mOval == null) {174             mOval = new RectF();175         }176         float start = getMinLength() * 0.5f * (1 - radiusRatio) + STOKE_WIDTH;177         float end = getMinLength() - start;178         mOval.set(start, start, end, end);179         return mOval;180     }181 182     private static final float RADIUS_RATIO_P = 0.2f;183 184     /**185      * 计算每一圈的半径比例186      *187      * @param index188      * @return189      */190     private float calcuRadiusRatio(int index) {191         return 1f - (CIRCLE_NUM - index - 1) * RADIUS_RATIO_P;192     }193 194     private int getMinLength() {195         return Math.min(getWidth(), getHeight());196     }197 198     @Override199     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {200         int minSize = (int) (STOKE_WIDTH * 4 * CIRCLE_NUM);201         int wantSize = (int) (STOKE_WIDTH * 8 * CIRCLE_NUM);202         int size = measureSize(widthMeasureSpec, wantSize, minSize);203         setMeasuredDimension(size, size);204     }205 206     /**207      * 测量view的宽高208      *209      * @param measureSpec210      * @param wantSize211      * @param minSize212      * @return213      */214     public static int measureSize(int measureSpec, int wantSize, int minSize) {215         int result = 0;216         int specMode = MeasureSpec.getMode(measureSpec);217         int specSize = MeasureSpec.getSize(measureSpec);218 219         if (specMode == MeasureSpec.EXACTLY) {220             // 父布局想要view的大小221             result = specSize;222         } else {223             result = wantSize;224             if (specMode == MeasureSpec.AT_MOST) {225                 // wrap_content226                 result = Math.min(result, specSize);227             }228         }229         //测量的尺寸和最小尺寸取大230         return Math.max(result, minSize);231     }232 }
     

values/attrs.xml

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       3     
      
        4         
        5         
        6         
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        8         
       
         9             
        10             
        11             
        12         
       13     
      14 
     

 

以上是自定义控件代码和资源文件。下面是如何使用自定义控件。

1 public class MainActivity extends Activity { 2     @Override 3     protected void onCreate(Bundle savedInstanceState) { 4         super.onCreate(savedInstanceState); 5         setContentView(R.layout.activity_main); 6         final WhorlView whorlView = (WhorlView) this.findViewById(R.id.whorl); 8         whorlView.setOnClickListener(new View.OnClickListener() { 9             @Override10             public void onClick(View v) {11                 if (whorlView.isCircling()) {12                     whorlView.stop();13                 } else {14                     whorlView.start();15                 }16             }17         });18     }19 }

values/color.xml

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     2 
     
      3     
      
       #F44336
      4     
      
       #4CAF50
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       #5677fc
      6