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Android自定义View圆形进度条控件的方法

这篇文章主要讲解了Android自定义View圆形进度条控件的方法，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。

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继续练习自定义View，这次带来的圆形进度条控件与之前的圆形百分比控件大同小异，这次涉及到了渐变渲染以及画布旋转等知识点，效果如下：

Android自定义View圆形进度条控件的方法

虽然步骤类似，但是我还是要写，毕竟基础的东西就是要多练

1、在res/values文件夹下新建attrs.xml文件，编写自定义属性：

<?xml version="1.0" encoding="utf-8"?>

2、新建CircleProgressView继承View，重写构造方法：

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

 public CircleProgressView(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
 }

 public CircleProgressView(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 }

3、在第三个构造方法中获取自定义属性的值：

 TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CircleProgressView, defStyleAttr, 0);
 mArcWidth = ta.getDimension(R.styleable.CircleProgressView_arcWidth, DensityUtils.dp2px(context, 8));
 mScaleCount = ta.getInteger(R.styleable.CircleProgressView_scaleCount, 24);
 mStartColor = ta.getColor(R.styleable.CircleProgressView_startColor, Color.parseColor("#3FC199"));
 mEndColor = ta.getColor(R.styleable.CircleProgressView_endColor, Color.parseColor("#3294C1"));
 mColorArray = new int[]{mStartColor, mEndColor};
 mLabelText = ta.getString(R.styleable.CircleProgressView_labelText);
 mTextColor = ta.getColor(R.styleable.CircleProgressView_textColor, Color.parseColor("#4F5F6F"));
 mProgressTextSize = ta.getDimension(R.styleable.CircleProgressView_progressTextSize, 160);
 mLabelTextSize = ta.getDimension(R.styleable.CircleProgressView_labelTextSize, 64);
 ta.recycle();

4、创建画图所使用的对象，如Paint、Rect、RectF：

 mArcBackPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mArcBackPaint.setStyle(Paint.Style.STROKE);
 mArcBackPaint.setStrokeWidth(mArcWidth);
 mArcBackPaint.setColor(Color.LTGRAY);

 mArcForePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mArcForePaint.setStyle(Paint.Style.STROKE);
 mArcForePaint.setStrokeWidth(mArcWidth);

 mArcRectF = new RectF();

 mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mLinePaint.setStyle(Paint.Style.STROKE);
 mLinePaint.setColor(Color.WHITE);
 mLinePaint.setStrokeWidth(DensityUtils.dp2px(context, 2));

 mProgressTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mProgressTextPaint.setStyle(Paint.Style.FILL);
 mProgressTextPaint.setColor(mTextColor);
 mProgressTextPaint.setTextSize(mProgressTextSize);

 mLabelTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mLabelTextPaint.setStyle(Paint.Style.FILL);
 mLabelTextPaint.setColor(mTextColor);
 mLabelTextPaint.setTextSize(mLabelTextSize);

 mTextRect = new Rect();

5、重写onMeasure()方法，计算自定义View的宽高：

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 setMeasuredDimension(measuredDimension(widthMeasureSpec), measuredDimension(heightMeasureSpec));
 }

 private int measuredDimension(int measureSpec) {
 int result;
 int mode = MeasureSpec.getMode(measureSpec);
 int size = MeasureSpec.getSize(measureSpec);
 if (mode == MeasureSpec.EXACTLY) {
 result = size;
 } else {
 result = 800;
 if (mode == MeasureSpec.AT_MOST) {
 result = Math.min(result, size);
 }
 }
 return result;
 }

6、重写onDraw()方法，绘制圆弧、刻度线和百分比文本、标签说明文本，注意坐标的计算：

 @Override
 protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 mArcRectF.set(mArcWidth / 2, mArcWidth / 2, getWidth() - mArcWidth / 2, getHeight() - mArcWidth / 2);
 //画背景弧线
 canvas.drawArc(mArcRectF, -90, 360, false, mArcBackPaint);
 //设置渐变渲染
 LinearGradient linearGradient = new LinearGradient(getWidth() / 2, 0, getWidth() / 2, getHeight(), mColorArray, null, Shader.TileMode.CLAMP);
 mArcForePaint.setShader(linearGradient);
 //画百分比值弧线
 canvas.drawArc(mArcRectF, -90, mSweepAngle, false, mArcForePaint);
 //画刻度线
 for (int i = 0; i < mScaleCount; i++) {
 canvas.drawLine(getWidth() / 2, 0, getWidth() / 2, mArcWidth, mLinePaint);
 //旋转画布
 canvas.rotate(360 / mScaleCount, getWidth() / 2, getHeight() / 2);
 }
 //画百分比文本
 String progressText = mProgress + "%";
 mProgressTextPaint.getTextBounds(progressText, 0, progressText.length(), mTextRect);
 float progressTextWidth = mTextRect.width();
 float progressTextHeight = mTextRect.height();
 canvas.drawText(progressText, getWidth() / 2 - progressTextWidth / 2,
 getHeight() / 2 + progressTextHeight / 2, mProgressTextPaint);
 //画标签说明文本
 mLabelTextPaint.getTextBounds(mLabelText, 0, mLabelText.length(), mTextRect);
 canvas.drawText(mLabelText, getWidth() / 2 - mTextRect.width() / 2,
 getHeight() / 2 - progressTextHeight / 2 - mTextRect.height(), mLabelTextPaint);
 }

7、暴露一个动态设置百分比的方法：

 public void setProgress(float progress) {
 Log.e("--> ", progress + "");
 ValueAnimator anim = ValueAnimator.ofFloat(mProgress, progress);
 anim.setDuration((long) (Math.abs(mProgress - progress) * 20));
 anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
 @Override
 public void onAnimationUpdate(ValueAnimator animation) {
 mProgress = (float) animation.getAnimatedValue();
 mSweepAngle = mProgress * 360 / 100;
 mProgress = (float) (Math.round(mProgress * 10)) / 10;//四舍五入保留到小数点后两位
 invalidate();
 }
 });
 anim.start();
 }

8、在activity_main.xml布局文件中使用该View：

<?xml version="1.0" encoding="utf-8"?>

9、在MainActivity中设置监听，传入百分比：

 final CircleProgressView view = (CircleProgressView) findViewById(R.id.circle_progress_view);
 view.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 float progress = (float) (Math.random() * 100);
 view.setProgress(progress);
 }
 });

看完上述内容，是不是对Android自定义View圆形进度条控件的方法有进一步的了解，如果还想学习更多内容，欢迎关注创新互联行业资讯频道。


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