public class ColorProgressBar extends View{  //下面這兩行在本demo中沒什么用，只是前幾天看別人的代碼時學到的按一定尺寸，設置其他尺寸的方式，自動忽略或者學習一下也不錯//  private int defaultStepIndicatorNum= (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,40,getResources().getDisplayMetrics());//  int mCircleRadius=0.28f*defaultStepIndicatorNum;  //布局的寬高  private int mWidth;  private int mHeight;  //直徑  private int mDiameter=500;  //底層圓畫筆  private Paint mPaintbg;  //頂層圓的畫筆  private Paint mPaintft;  //周圍線的畫筆  private Paint mPaintLine;  //外層線條的長度  private int mLongItem=dip2px(20);  //線條與圓的間距  private int mDistanceItem=dip2px(10);  //進度條的最大寬度（取底層進度條與頂層進度條寬度最大的）  private int mProgressWidth;  //底層圓的顏色  private int mBackColor;  //頂層圓的顏色  private int mFrontColor;  //底層圓、頂層圓的寬度  private float mBackWidth;  private float mFrontWidth;  //設置進度  private float currentvalue;  //通過動畫演示進度  private ValueAnimator animator;  private int curvalue;  public ColorProgressBar(Context context) {    this(context,null,0);  }  public ColorProgressBar(Context context, AttributeSet attrs) {    this(context, attrs,0);  }  public ColorProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    TypedArray ta=context.obtainStyledAttributes(attrs, R.styleable.ColorProgressBar);    mBackColor= ta.getColor(R.styleable.ColorProgressBar_back_color, Color.BLACK);    mFrontColor=ta.getColor(R.styleable.ColorProgressBar_front_color,mBackColor);    mBackWidth=ta.getDimension(R.styleable.ColorProgressBar_back_width,dip2px(10));    mFrontWidth=ta.getDimension(R.styleable.ColorProgressBar_front_width,dip2px(10));    mProgressWidth=mBackWidth>mFrontWidth?(int)mBackWidth:(int)mFrontWidth;    //注意釋放資源    ta.recycle();    init();  }  /**   * 都是畫筆初始化   */  private void init() {    mPaintbg=new Paint(Paint.ANTI_ALIAS_FLAG);    mPaintbg.setStrokeWidth(mProgressWidth);    mPaintbg.setColor(mBackColor);    mPaintbg.setStrokeCap(Paint.Cap.ROUND);    mPaintbg.setStyle(Paint.Style.STROKE);    mPaintft=new Paint(Paint.ANTI_ALIAS_FLAG);    mPaintft.setColor(mFrontColor);    mPaintft.setStyle(Paint.Style.STROKE);    mPaintft.setStrokeWidth(mFrontWidth);    mPaintft.setStrokeCap(Paint.Cap.ROUND);    mPaintLine=new Paint(Paint.ANTI_ALIAS_FLAG);    mPaintLine.setColor(Color.BLACK);    mPaintLine.setStrokeWidth(5);  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);//   寬度=高度=（長指針+指針與圓盤的間距+進度條的粗細+半徑）*2    Log.e("測量數據","LongItem："+mLongItem+"mDistanceItem:"+mDistanceItem+"mProgressWidth:"+mProgressWidth+"mDiameter:"+mDiameter/2);    mWidth=(int)2*(mLongItem+mDistanceItem+mProgressWidth*2+mDiameter/2);    mHeight=(int)2*(mLongItem+mDistanceItem+mProgressWidth*2+mDiameter/2);    Log.e("自定義View","高度"+mHeight+"寬度"+mWidth);    setMeasuredDimension(mWidth,mHeight);  }  @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    //繪制底層圓弧，矩形的具體計算見圖片    canvas.drawArc(new RectF(mProgressWidth/2+mDistanceItem+mLongItem,mProgressWidth/2+mDistanceItem+mLongItem,mWidth-mProgressWidth/2-mDistanceItem-mLongItem,mHeight-mProgressWidth/2-mDistanceItem-mLongItem),0,360,true,mPaintbg);//    SweepGradient gradient=new SweepGradient();    //繪制邊緣線    canvas.save();    canvas.rotate(144,mWidth/2,mHeight/2);    for(int i=0;i<=30;i++){      canvas.rotate(-9,mWidth/2,mHeight/2);      if(i%5==0){        canvas.drawLine(mWidth/2,5,mWidth/2,mLongItem,mPaintbg);      }else {        canvas.drawLine(mWidth/2,25,mWidth/2,mLongItem,mPaintLine);      }    }    canvas.restore();    //給畫筆設置漸變    SweepGradient sweepGradient=new SweepGradient(mWidth/2,mHeight/2,Color.RED,Color.YELLOW);    mPaintft.setShader(sweepGradient);    //繪制頂層圓弧，currentvalue在改變時呈現動態效果    canvas.drawArc(new RectF(mProgressWidth/2+mDistanceItem+mLongItem,mProgressWidth/2+mDistanceItem+mLongItem,mWidth-mProgressWidth/2-mDistanceItem-mLongItem,mHeight-mProgressWidth/2-mDistanceItem-mLongItem),135,currentvalue,false,mPaintft);    mPaintft.setTextSize(100);    mPaintft.setTextAlign(Paint.Align.CENTER);    //繪制文本    canvas.drawText(String.format("%.0f",currentvalue),mWidth/2,mHeight/2+50,mPaintft);    invalidate();  }  /**   * 設置動畫   * @param value   */  public void setCurrentValue(float value){//    currentvalue=value;    animator=ValueAnimator.ofFloat(currentvalue,value);    animator.setDuration(3000);    animator.setTarget(currentvalue);    animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {      @Override      public void onAnimationUpdate(ValueAnimator valueAnimator) {        currentvalue= (float) valueAnimator.getAnimatedValue();        curvalue=curvalue/10;      }    });    animator.start();  }  private int dip2px(float dip){    float density=getContext().getResources().getDisplayMetrics().density;    return (int)(dip*density+0.5f);  }}

 @Override  protected void onCreate(@Nullable Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.colorprogressbar);    mBtStart1= (Button) findViewById(R.id.bt1);    bar1= (ColorProgressBar) findViewById(R.id.cp1);    mBtStart1.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        bar1.setCurrentValue(270);      }    });  }

 <declare-styleable name="ColorProgressBar">    <attr name="back_color" format="color"></attr>    <attr name="front_color" format="color"></attr>    <attr name="back_width" format="dimension"></attr>    <attr name="front_width" format="dimension"></attr>  </declare-styleable>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="vertical">    <Button      android:id="@+id/bt1"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:text="start1"/>    <com.demo.demo.networkdemo.colorprogressbar.widget.ColorProgressBar      android:id="@+id/cp1"      android:layout_width="232dp"      android:layout_height="match_parent"      android:layout_gravity="center_horizontal"      app:back_color="@color/colorPrimary"      app:front_color="@color/colorAccent"      android:background="@mipmap/ic_launcher"/>  </LinearLayout>