Android实现渐变圆环、圆形进度条效果

package com.jky.mobile_xmxt.view; import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.graphics.SweepGradient;import android.util.AttributeSet;import android.view.View;import android.view.animation.Animation;import android.view.animation.Transformation; import com.jky.mobile_xmxt.R; import java.text.DecimalFormat; /** * 圆盘计步图表 */public class CircleProgressBar extends View {  private RectF mWheelRect = new RectF(); private Paint mDefaultWheelPaint; private Paint mFinishWheelPaint; private Paint mCenterWheelPaint; private Paint mTitlePaint, mStepPaint, mTargetPaint; private float mCircleStrokeWidth; private float mSweepAnglePer; private float mPercent; private int mStepNum, mCurrStepNum; private float pressExtraStrokeWidth; private BarAnimation mAnim; private int mMaxStepNum;// 默认最大步数 private float mTitleY, mStepY, mTargetY; private DecimalFormat mDecimalFormat = new DecimalFormat("#.0");// 格式为保留小数点后一位 public static String GOAL_STEP; public static String PERCENT;  public CircleProgressBar(Context context) { super(context); init(null, 0); }  public CircleProgressBar(Context context, AttributeSet attrs) { super(context, attrs); init(attrs, 0); }  public CircleProgressBar(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(attrs, defStyle); }  private void init(AttributeSet attrs, int defStyle) {  mFinishWheelPaint = new Paint(); mFinishWheelPaint.setColor(Color.rgb(100, 113, 205)); mFinishWheelPaint.setStyle(Paint.Style.STROKE);// 空心 mFinishWheelPaint.setStrokeCap(Paint.Cap.ROUND);// 圆角画笔 mFinishWheelPaint.setAntiAlias(true);// 去锯齿  mCenterWheelPaint = new Paint(); mCenterWheelPaint.setColor(Color.rgb(243, 243, 243)); mCenterWheelPaint.setStyle(Paint.Style.STROKE); mCenterWheelPaint.setStrokeCap(Paint.Cap.ROUND); mCenterWheelPaint.setAntiAlias(true);  mDefaultWheelPaint = new Paint(); mDefaultWheelPaint.setColor(Color.rgb(127, 127, 127)); mDefaultWheelPaint.setStyle(Paint.Style.STROKE); mDefaultWheelPaint.setStrokeCap(Paint.Cap.ROUND); mDefaultWheelPaint.setAntiAlias(true);  mTitlePaint = new Paint(); mTitlePaint.setAntiAlias(true); mTitlePaint.setColor(Color.WHITE);  mStepPaint = new Paint(); mStepPaint.setAntiAlias(true); mStepPaint.setColor(Color.WHITE);  mTargetPaint = new Paint(); mTargetPaint.setAntiAlias(true); mTargetPaint.setColor(Color.WHITE); mAnim = new BarAnimation(); }  @Override protected void onDraw(Canvas canvas) { canvas.drawArc(mWheelRect, 0, 359, false, mDefaultWheelPaint); canvas.drawArc(mWheelRect, 0, 359, false, mCenterWheelPaint); canvas.drawArc(mWheelRect, 90, mSweepAnglePer, false, mFinishWheelPaint);// canvas.drawText("步数", mWheelRect.centerX() - (mTitlePaint.measureText("步数") / 2), mTitleY,// mTitlePaint); canvas.drawText(mCurrStepNum + "",  mWheelRect.centerX() - (mStepPaint.measureText(String.valueOf(mCurrStepNum)) / 2), mStepY,  mStepPaint); String description = ""; float percent = getPercent(); if(percent > 0.5){  description ="严重污染"; }else if(percent<0.5){  description ="中等污染"; }else{  description ="普通污染"; }  canvas.drawText(description , mWheelRect.centerX() -  (mTargetPaint.measureText(description) / 2), mTargetY, mTargetPaint); SweepGradient sweepGradient = new SweepGradient(mWheelRect.centerX(), mWheelRect.centerY(),  new int[]{getResources().getColor(R.color.color_environment_severe), getResources().getColor(R.color.color_environment_serious),   getResources().getColor(R.color.color_environment_excellent),   getResources().getColor(R.color.color_environment_good), getResources().getColor(R.color.color_environment_mild),   getResources().getColor(R.color.color_environment_moderate)}, null); mFinishWheelPaint.setShader(sweepGradient); }  @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int height = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec); int width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec); int min = Math.min(width, height);// 获取View最短边的长度 setMeasuredDimension(min, min);// 强制改View为以最短边为长度的正方形 mCircleStrokeWidth = getTextScale(15, min);// 圆弧的宽度 pressExtraStrokeWidth = getTextScale(10, min);// 圆弧离矩形的距离 mWheelRect.set(mCircleStrokeWidth + pressExtraStrokeWidth, mCircleStrokeWidth + pressExtraStrokeWidth,  min - mCircleStrokeWidth - pressExtraStrokeWidth, min - mCircleStrokeWidth - pressExtraStrokeWidth);// 设置矩形 mTitlePaint.setTextSize(getTextScale(60, min)); mStepPaint.setTextSize(getTextScale(120, min)); mTargetPaint.setTextSize(getTextScale(40, min)); mTitleY = getTextScale(170, min); mStepY = getTextScale(300, min); mTargetY = getTextScale(380, min); mFinishWheelPaint.setStrokeWidth(mCircleStrokeWidth); mCenterWheelPaint.setStrokeWidth(mCircleStrokeWidth); mDefaultWheelPaint.setStrokeWidth(mCircleStrokeWidth - getTextScale(2, min)); mDefaultWheelPaint.setShadowLayer(getTextScale(10, min), 0, 0, Color.rgb(127, 127, 127));// 设置阴影 }  /** * 进度条动画 * * @author Administrator */ public class BarAnimation extends Animation {  /**  * 每次系统调用这个方法时， 改变mSweepAnglePer，mPercent，stepnumbernow的值，  * 然后调用postInvalidate()不停的绘制view。  */ @Override protected void applyTransformation(float interpolatedTime, Transformation t) {// if (interpolatedTime < 1.0f) {// mPercent = Float.parseFloat(mDecimalFormat.format(interpolatedTime * mStepNum * 100f / mMaxStepNum));// 将浮点值四舍五入保留一位小数// mSweepAnglePer = interpolatedTime * mStepNum * 360 / mMaxStepNum;// mCurrStepNum = (int) (interpolatedTime * mStepNum);// } else {  mPercent = Float.parseFloat(mDecimalFormat.format(mStepNum * 100f / mMaxStepNum));// 将浮点值四舍五入保留一位小数  if (mPercent > 100.0f) {  mPercent = 100.0f;  }  PERCENT = String.valueOf(mPercent);  mSweepAnglePer = mStepNum * 360 / mMaxStepNum;  mCurrStepNum = mStepNum;// }   requestLayout(); } }  public float getPercent() { return mPercent; }  /** * 根据控件的大小改变绝对位置的比例 * * @param n * @param m * @return */ public float getTextScale(float n, float m) { return n / 500 * m; }  /** * 更新步数和设置一圈动画时间 * * @param stepCount * @param time */ public void update(int stepCount, int time) { this.mStepNum = stepCount; mAnim.setDuration(time); // setAnimationTime(time); this.startAnimation(mAnim); }  /** * @param stepNum */ public void setMaxStepNum(int stepNum) { mMaxStepNum = stepNum; GOAL_STEP = String.valueOf(mMaxStepNum); }  public void setColor(int color) { mFinishWheelPaint.setColor(color); mStepPaint.setColor(color); }  /** * 设置动画时间 * * @param time */ public void setAnimationTime(int time) { mAnim.setDuration(time * mStepNum / mMaxStepNum);// 按照比例设置动画执行时间 } }

<com.jky.mobile_xmxt.view.CircleProgressBar android:id="@+id/color_progress_view" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="6" />

color_progress_view = (CircleProgressBar)view.findViewById(R.id.color_progress_view);color_progress_view.setMaxStepNum(500);color_progress_view.update(470,1000);