Android开发自定义控件实现一个圆形进度条【带数值和动画】

实现一个如下图所示的自定义控件，可以直观地展示某个球队在某个赛季的积分数和胜场、负场、平局数

首先对画布进行区域划分，整个控件分上下两部分

上边是个大的圆环，圆环中间两行文字，没什么难度，选好圆心坐标和半径后直接绘制即可，绘制文字也是如此。

下部分是三个小的圆弧进度条，弧的末端绘制一个小的实心圆

首先选好坐标和半径，然后先绘制三个圆环作为弧形进度条的背景

之后从12点钟开始绘制进度弧，知道了圆环的圆心和半径，也知道了弧对应于12点钟和圆环圆心的偏移角度

通过三角函数可以计算出进度弧终点坐标，以进度弧终点坐标为圆心绘制一个小的实心圆即可

动画效果通过Handler的postDelayed方法触发重绘即可实现

在项目中的效果如图所示：

测试代码如下：

final Random random=new Random();final ScoreBoardView myView=(ScoreBoardView)findViewById(R.id.custom_view);myView.setOnClickListener(new View.OnClickListener(){    @Override    public void onClick(View v){        myView.setColor(Color.BLUE);        myView.setScore(random.nextInt(28));        myView.setWinDrawLose(random.nextInt(12),random.nextInt(15),random.nextInt(26));    }});

完整代码如下:

public class ScoreBoardView extends View {    private Context context;    /*弧的颜色*/    private int mColor;    /*积分数，胜场数，平局数，负场数*/    private int mScore, mWinNumber, mDrawNumber, mLoseNumber;    /*传入数字的最大值*/    private final int FULL_SCORE = 30;    /*动画插值器*/    DecelerateInterpolator mDecelerateInterpolator = new DecelerateInterpolator();    /*动画持续时间（刷新次数）*/    private int mDuration = 10;    /*动画刷新过程中的当前值*/    private int mCurrentTime = 0;    private TypedValue typedValue;    private TypedValue typedValue1;    private Handler mHandler = new Handler();    private Runnable mAnimation = new Runnable() {        @Override        public void run() {            if (mCurrentTime < mDuration) {                mCurrentTime++;                /*导致重绘调用onDraw，onDraw最后再次postDelay执行此动画，直到达到指定的次数*/                ScoreBoardView.this.invalidate();            }        }    };    /*绘制图形*/    private Paint paint = new Paint();    /*绘制文字*/    private Paint paintText = new Paint();    public ScoreBoardView(Context context) {        super(context);        this.context=context;        init();    }    public ScoreBoardView(Context context, AttributeSet attrs) {        super(context, attrs);        this.context=context;        init();    }    public ScoreBoardView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        this.context=context;        init();    }        private void init() {        /*数据初始化，默认属性*/        mColor = Color.rgb(95, 112, 72);        mScore = 0;        mWinNumber = 0;        mDrawNumber = 0;        mLoseNumber = 0;        typedValue=new TypedValue();        typedValue1=new TypedValue();        context.getTheme().resolveAttribute(R.attr.maintextclor, typedValue, true);        context.getTheme().resolveAttribute(R.attr.maintextclor_reverse,typedValue1,true);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        /*获取控件总的宽高*/        float totalWidth = getWidth();        float totalHeight = getHeight();        /*        * DecelerateInterpolator：动画从开始到结束，变化率是一个减速的过程。        * AccelerateInterpolator：动画从开始到结束，变化率是一个加速的过程。        * CycleInterpolator：动画从开始到结束，变化率是循环给定次数的正弦曲线        * AccelerateDecelerateInterpolator：动画从开始到结束，变化率是先加速后减速的过程。        * LinearInterpolator：动画从开始到结束，变化率是线性变化。        * */        /*计算当前时刻动画进度值*/        float AnimCurrentValue =mDecelerateInterpolator.getInterpolation(1.0f * mCurrentTime / mDuration);        /*图形画笔设置*/        paint.setAntiAlias(true);        paint.setStyle(Paint.Style.STROKE);        /*积分数，上边的大圆*/        paint.setStrokeWidth(4);        paint.setColor(mColor);        /*积分大圆的中心坐标和半径*/        float score_radius = totalHeight * 1 / 5, score_circle_x = totalWidth / 2, score_circle_y = totalHeight / 3;        /*绘制圆弧*/        canvas.drawCircle(score_circle_x, score_circle_y, score_radius, paint);        /*文字画笔基本设置*/        paintText.setAntiAlias(true);        paintText.setStyle(Paint.Style.STROKE);        /*文字从中间开始绘制*/        /*Paint.Align.CENTER：The text is drawn centered horizontally on the x,y origin*/        paintText.setTextAlign(Paint.Align.CENTER);        /*文字画笔大小和颜色设置*/        paintText.setTextSize(score_radius * 3 / 4);        paintText.setColor(getResources().getColor(typedValue.resourceId));        /*圆心位置绘制积分数值*/        canvas.drawText("" + mScore, score_circle_x, score_circle_y, paintText);        /*缩小字体绘制文本信息*/        paintText.setTextSize(score_radius * 1 / 4);        paintText.setAlpha(80);        /*圆心下边绘制文本*/        canvas.drawText("积分", score_circle_x, score_circle_y + score_radius / 2, paintText);        /*设置画笔，画下边的三个小圆*/        paint.setStrokeWidth(4);        paint.setAlpha(255);        /*下边三个小圆的半径*/        float small_radius = totalHeight / 10;        /*三个小圆的圆心的x坐标*/        float[] circleXs = new float[]{totalWidth / 2 - score_radius * 3 / 2,                                        totalWidth / 2,                                        totalWidth / 2 + score_radius * 3 / 2};        /*三个小圆的圆心的y坐标*/        float circleY = totalHeight * 3 / 4;        /*计算三个小圆弧扫过的角度*/        float[] theta_values = new float[]{360 * mWinNumber / FULL_SCORE* AnimCurrentValue,                                            360 * mDrawNumber / FULL_SCORE* AnimCurrentValue,                                            360 * mLoseNumber / FULL_SCORE* AnimCurrentValue};        /*设置画笔颜色，绘制外围圆环*/        paint.setColor(getResources().getColor(typedValue1.resourceId));        /*分别绘制三个外围圆环*/        canvas.drawCircle(circleXs[0], circleY, small_radius, paint);//画WIN背景圆        canvas.drawCircle(circleXs[1], circleY, small_radius, paint);//画DRAW背景圆        canvas.drawCircle(circleXs[2], circleY, small_radius, paint);//画LOSE背景圆        /*更改画笔颜色，绘制圆弧进度条*/        paint.setColor(mColor);        /*drawArc的起始角度是3点钟方向，因此要从12点钟方向开始绘制，起始角度为270度*/        canvas.drawArc(new RectF(circleXs[0] - small_radius,                                 circleY - small_radius,                                 circleXs[0] + small_radius,                                 circleY + small_radius),                        270, theta_values[0], false, paint);//画WIN圆形进度条        canvas.drawArc(new RectF(circleXs[1] - small_radius,                                 circleY - small_radius,                                 circleXs[1] + small_radius,                                 circleY + small_radius),                        270, theta_values[1], false, paint);//画DRAW圆形进度条        canvas.drawArc(new RectF(circleXs[2] - small_radius,                                 circleY - small_radius,                                 circleXs[2] + small_radius,                                 circleY + small_radius),                        270, theta_values[2], false, paint);//画LOSE圆形进度条        /*绘制圆弧结束处的小圆点，实心圆*/        paint.setStyle(Paint.Style.FILL);        /*已知半径、圆心位置、便宜角度，根据三角函数很方便计算出小实心圆圆心坐标*/        canvas.drawCircle(circleXs[0] + small_radius * (float) Math.sin(theta_values[0] * Math.PI / 180),                circleY - small_radius * (float) Math.cos(theta_values[0] * Math.PI / 180), 6, paint);//画WIN末尾小圆点        canvas.drawCircle(circleXs[1] + small_radius * (float) Math.sin(theta_values[1] * Math.PI / 180),                circleY - small_radius * (float) Math.cos(theta_values[1] * Math.PI / 180), 6, paint);//画DRAW末尾小圆点        canvas.drawCircle(circleXs[2] + small_radius * (float) Math.sin(theta_values[2] * Math.PI / 180),                circleY - small_radius * (float) Math.cos(theta_values[2] * Math.PI / 180), 6, paint);//画LOSE末尾小圆点        /*绘制文字*/        paintText.setColor(getResources().getColor(typedValue.resourceId));        paintText.setTextSize(small_radius * 2 / 3);        /*测量文字大小，确定绘制文字时垂直方向的位置*/        Paint.FontMetrics fontMetrics = paint.getFontMetrics();        float textBaseLineOffset = (fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom;        /*在三个小圆的正中心位置绘制相应的数字*/        canvas.drawText("" + (int)(mWinNumber * AnimCurrentValue), circleXs[0], circleY + textBaseLineOffset, paintText);        canvas.drawText("" + (int)(mDrawNumber * AnimCurrentValue), circleXs[1], circleY + textBaseLineOffset, paintText);        canvas.drawText("" + (int)(mLoseNumber * AnimCurrentValue), circleXs[2], circleY + textBaseLineOffset, paintText);        /*调整字体大小，绘制文本信息*/        paintText.setTextSize(small_radius * 4 / 9);        canvas.drawText("胜场", circleXs[0], circleY - small_radius*4/3, paintText);        canvas.drawText("平局", circleXs[1], circleY - small_radius*4/3, paintText);        canvas.drawText("负场", circleXs[2], circleY - small_radius*4/3, paintText);        /*20ms刷新一次数据*/        mHandler.postDelayed(mAnimation, 20);//启动动画    }    public void setColor(int mColor) {        this.mColor = mColor;        invalidate();    }    public void setScore(int score) {        this.mScore = score;        invalidate();    }    public void setWinDrawLose(int win,int draw,int lose) {        this.mWinNumber = win;        this.mDrawNumber = draw;        this.mLoseNumber = lose;        mCurrentTime =0;        invalidate();    }}