1.分解步骤

• 1.分析效果
• 2.确定自定义属性，编写attrs.xml
• 3.在布局中使用
• 4.在自定义view中获取属性
• 5.onMeacher()
• 5.ondraw（）画图 画外圆弧 画内圆弧 画文字
• 6.其他处理（动画效果）

2.具体步骤

• attrs.xml文件 定义需要的控件内部属性变量

<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="QQsetView">
    <attr name="outerColor" format="color"/>
    <attr name="innerColor" format="color"/>
    <attr name="borderWidth" format="dimension"/>
    <attr name="stepTextSize" format="dimension"/>
    <attr name="stepTextColor" format="color"/>
</declare-styleable>
</resources>

• 在layout布局中使用

<com.incall.apps.qqsetview.QQsetView
    android:id="@+id/step"
    app:outerColor="@color/blue"
    app:innerColor="@color/red"
    app:stepTextSize="50sp"
    app:stepTextColor="@color/red"
    app:borderWidth="6dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

• 编写控件类QQsetView.class

public class QQsetView extends View {

    private int mOuterColor = Color.BLUE;//外圆环颜色
    private int mInnerColor = Color.RED;//内圆环颜色
    private int mBorderWidth = 20;//圆环宽度
    private int mStepTextSize = 16;//文字字体大小
    private int mStepTextColor = Color.RED;//文字颜色
    private Paint mOutPaint, mInnerPaint, mTextPaint;//外圆环，内圆环，文字画笔

    private int mCurrentStep = 0;//当前步数
    private int mStepMax = 0;//最大（总共）步数

    public QQsetView(Context context) {
        this(context, null);
    }

    public QQsetView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public QQsetView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public QQsetView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);


        //4.在自定义view中获取属性
        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.QQsetView);
        mOuterColor = array.getColor(R.styleable.QQsetView_outerColor, mOuterColor);
        mInnerColor = array.getColor(R.styleable.QQsetView_innerColor, mInnerColor);
        mBorderWidth = (int) array.getDimension(R.styleable.QQsetView_borderWidth, mBorderWidth);
        mStepTextSize = array.getDimensionPixelSize(R.styleable.QQsetView_stepTextSize, mStepTextSize);
        mStepTextColor = array.getColor(R.styleable.QQsetView_stepTextColor, mStepTextColor);

        //定义外弧画笔
        mOutPaint = new Paint();
        mOutPaint.setColor(mOuterColor);
        mOutPaint.setAntiAlias(true);
        mOutPaint.setStrokeWidth(mBorderWidth);
        mOutPaint.setStrokeCap(Paint.Cap.ROUND);
        mOutPaint.setStyle(Paint.Style.STROKE);//画笔空心

        //定义内弧画笔
        mInnerPaint = new Paint();
        mInnerPaint.setColor(mInnerColor);
        mInnerPaint.setAntiAlias(true);
        mInnerPaint.setStrokeWidth(mBorderWidth);
        mInnerPaint.setStrokeCap(Paint.Cap.ROUND);
        mInnerPaint.setStyle(Paint.Style.STROKE);//画笔空心

        //定义文字画笔
        mTextPaint = new Paint();
        mTextPaint.setColor(mStepTextColor);
        mTextPaint.setAntiAlias(true);
        mTextPaint.setTextSize(mStepTextSize);
        //回收
        array.recycle();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //判断设置的何种模式
        //获取模式AT_MOST 40dp
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        //高度不一致，取最小值，以确保为正方形
        setMeasuredDimension(width > height ? height : width, width > height ? height : width);
    }

    //5.画图 画外圆弧 画内圆弧 画文字
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        //定义圆心 半径
        int center = getWidth() / 2;
        int radius = getWidth() / 2 - mBorderWidth / 2;
        RectF rectF = new RectF(center - radius, center - radius, center + radius, center + radius);
        //外弧
        canvas.drawArc(rectF, 135, 270, false, mOutPaint);
        //内弧
        float sweepAngle = (float) mCurrentStep / mStepMax;
        if (sweepAngle == 0) {
            return;
        }
        canvas.drawArc(rectF, 135, sweepAngle * 270, false, mInnerPaint);
        //文字
        //dx 文字左侧偏移量
        String stepText = mCurrentStep + "";
        Rect textBounds = new Rect();
        mTextPaint.getTextBounds(stepText, 0, stepText.length(), textBounds);
        int dx = getWidth() / 2 - textBounds.width() / 2;
        //基线baseline
        Paint.FontMetricsInt fontMetricsInt = mTextPaint.getFontMetricsInt();
        int dy = (fontMetricsInt.bottom - fontMetricsInt.top) / 2 - fontMetricsInt.bottom;
        int baseLine = getHeight() / 2 + dy;
        canvas.drawText(stepText, dx, baseLine, mTextPaint);
    }

    //其他，设置动画

    public synchronized void setmCurrentStep(int mCurrentStep) {
        this.mCurrentStep = mCurrentStep;
        invalidate();
    }

    public synchronized void setmStepMax(int mStepMax) {
        this.mStepMax = mStepMax;
        invalidate();
    }
}

• MainActivity类

        QQsetView qQsetstep = findViewById(R.id.step);
        qQsetstep.setmStepMax(4000);
        //属性动画
        ValueAnimator valueAnimator = ObjectAnimator.ofFloat(0, 3000);
        valueAnimator.setDuration(1000);
        valueAnimator.setInterpolator(new DecelerateInterpolator());//插值器
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                float currentStep =  (float)animation.getAnimatedValue();
                qQsetstep.setmCurrentStep((int) currentStep);
            }
        });
        valueAnimator.start();

3.效果图

进度圆环.gif