Android绘制圆形百分比加载圈效果

/**
 * 绘制圆
 * @param cx   圆心x坐标
 * @param cy   圆心y坐标
 * @param radius 圆的半径
 * @param paint 画笔
 */
 public void drawCircle(float cx, float cy, float radius, @NonNull Paint paint) {
 ...
 }


/**
 * 绘制圆弧
 * @param oval    决定圆弧范围的矩形区域
 * @param startAngle 开始角度
 * @param sweepAngle 绘制的角度
 * @param useCenter 是否需要连接圆心,true连接,false不连接
 * @param paint   画笔
 */
 public void drawArc(RectF oval, float startAngle, float sweepAngle, boolean useCenter,Paint paint) {
  ...
 }


 /**
  * 绘制文本
  * @param text 需要绘制的字符串
  * @param x   绘制文本起点x坐标,注意文本比较特殊,它的起点是左下角的x坐标
  * @param y   绘制文本起点y坐标,同样是左下角的y坐标
  * @param paint 画笔
  */
 public void drawText(String text, float x, float y, Paint paint) {
  ...
 }

public class CircleProgressView extends View {
  private int width;//控件宽度
  private int height;//控件高
  private float radius;//半径
  private float pointX;//圆心x坐标
  private float pointY;//圆心y坐标
  private int circleBackgroundColor;//背景颜色
  private int circleBackgroundAlpha; //背景透明度
  private int circleRingColor;//进度颜色
  private int progressTextColor;//进度文本的颜色
  private int progressTextSize;//进度文本的字体大小
  private int circleRingWidth; //进度的宽度
  private Paint mPaint;
  private int progress;//进度值
  private boolean isRingStyle;//是否是空心的圆环进度样式

  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);
    circleBackgroundColor = Color.WHITE;
    circleRingColor = Color.parseColor("#3A91FF");
    progressTextColor = Color.BLACK;
    circleBackgroundAlpha = 128;
    progressTextSize = 32;
    circleRingWidth = 10;
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setStyle(Paint.Style.FILL);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    width = getMeasuredWidth();
    height = getMeasuredHeight();
    radius = Math.min(width, height) / 2.0f;
    pointX = width / 2.0f;
    pointY = height / 2.0f;
  }

  @Override
  protected void onDraw(Canvas canvas) {
    drawBackground(canvas);
    drawCircleRing(canvas);
    drawProgressText(canvas);
  }

  /**
   * 绘制背景色
   *
   * @param canvas
   */
  private void drawBackground(Canvas canvas) {
    mPaint.setColor(circleBackgroundColor);
    mPaint.setAlpha(circleBackgroundAlpha);
    canvas.drawCircle(pointX, pointY, radius, mPaint);
  }

  /**
   * 绘制圆环
   *
   * @param canvas
   */
  private void drawCircleRing(Canvas canvas) {
    mPaint.setColor(circleRingColor);
    RectF oval = new RectF();
    if (isRingStyle) {
      mPaint.setStyle(Paint.Style.STROKE);
      mPaint.setStrokeWidth(circleRingWidth);
      mPaint.setStrokeCap(Paint.Cap.ROUND);
      //注意:定义圆环的矩形区域是需要考虑圆环的宽度
      oval.left = circleRingWidth / 2.0f;
      oval.top = height / 2.0f - radius + circleRingWidth / 2.0f;
      oval.right = 2 * radius - circleRingWidth / 2.0f;
      oval.bottom = height / 2.0f + radius - circleRingWidth / 2.0f;
      canvas.drawArc(oval, 0, 360 * progress / 100, false, mPaint);
    } else {
      mPaint.setStyle(Paint.Style.FILL);
      oval.left = 0;
      oval.top = height / 2.0f - radius;
      oval.right = 2 * radius;
      oval.bottom = height / 2.0f + radius;
      canvas.drawArc(oval, 0, 360 * progress / 100, true, mPaint);
    }

  }

  /**
   * 绘制进度文本
   *
   * @param canvas
   */
  private void drawProgressText(Canvas canvas) {
    mPaint.setColor(progressTextColor);
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setTextSize(progressTextSize);
    Rect textBound = new Rect();
    String text = progress + "%";
    //获取文本的矩形区域到textBound中
    mPaint.getTextBounds(text, 0, text.length(), textBound);
    int textWidth = textBound.width();
    int textHeight = textBound.height();
    float x = pointX - textWidth / 2.0f;
    float y = pointY + textHeight / 2.0f;
    canvas.drawText(text, x, y, mPaint);
  }

  /**
   * 更新进度
   *
   * @param progress
   */
  public void setValue(int progress) {
    this.progress = progress;
    invalidate();
  }

  /**
   * 设置进度圆环的样式
   *
   * @param isRing true是空心的圆环,false表示实心的圆环
   */
  public void setCircleRingStyle(boolean isRing) {
    this.isRingStyle = isRing;
  }

  /**
   * 设置背景透明度
   *
   * @param alpha 0~255
   */
  public void setCircleBackgroundAlpha(int alpha) {
    this.circleBackgroundAlpha = alpha;
  }

  /**
   * 设置进度文本的大小
   * @param progressTextSize
   */
  public void setProgressTextSize(int progressTextSize) {
    this.progressTextSize = progressTextSize;
  }

  /**
   * 设置进度文本的颜色
   * @param progressTextColor
   */
  public void setProgressTextColor(int progressTextColor) {
    this.progressTextColor = progressTextColor;
  }
}

public class MainActivity extends AppCompatActivity {
  private CircleProgressView mCircleProgressView;
  private int progress;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mCircleProgressView = (CircleProgressView) findViewById(R.id.progressView);
    mCircleProgressView.setCircleRingStyle(false);//实心圆
    HandlerThread thread = new HandlerThread("draw-thread");
    thread.start();
    Handler tHandler = new Handler(thread.getLooper()) {
      @Override
      public void handleMessage(Message msg) {
        runOnUiThread(new Runnable() {
          @Override
          public void run() {
            mCircleProgressView.setValue(progress++);

          }
        });
        if (progress <100) {
          sendEmptyMessageDelayed(0, 100);
        }
      }
    };
    tHandler.sendEmptyMessage(0);
  }
}

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