CircularProgressBar.java

package com.lqr.wechat.widget;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;

/**
 * 环形的进度条
 * 
 * @author lwz <lwz0316@gmail.com>
 */
public class CircularProgressBar extends View {
	
	private int mDuration = 100;
	private int mProgress = 30;
	
	private Paint mPaint = new Paint();
	private RectF mRectF = new RectF();
	
	private int mBackgroundColor = Color.LTGRAY;
	private int mPrimaryColor = Color.parseColor("#6DCAEC");
	private float mStrokeWidth = 10F;
	
	/**
	 * 进度条改变监听
	 * 
	 * {@link #onChange( int duration, int progress, float rate)}
	 */
	public interface OnProgressChangeListener {
		/**
		 * 进度改变事件，当进度条进度改变，就会调用该方法
		 * @param duration 总进度
		 * @param progress 当前进度
		 * @param rate 当前进度与总进度的商 即：rate = (float)progress / duration
		 */
		public void onChange(int duration, int progress, float rate);
	}
	
	private OnProgressChangeListener mOnChangeListener;
	
	/**
	 * 设置进度条改变监听
	 * @param l
	 */
	public void setOnProgressChangeListener(OnProgressChangeListener l) {
		mOnChangeListener = l;
	}
	
	public CircularProgressBar(Context context) {
		super(context);
	}
	
	public CircularProgressBar(Context context, AttributeSet attrs) {
		super(context, attrs);
	}
	
	/**
	 * 设置进度条的最大值, 该值要 大于 0
	 * @param max
	 */
	public void setMax( int max ) {
		if( max < 0 ) {
			max = 0;
		}
		mDuration = max;
	}
	
	/**
	 * 得到进度条的最大值
	 * @return
	 */
	public int getMax() {
		return mDuration;
	}
	
	/**
	 * 设置进度条的当前的值
	 * @param progress 
	 */
	public void setProgress( int progress ) {
		if( progress > mDuration ) {
			progress = mDuration;
		}
		mProgress = progress;
		if( mOnChangeListener != null ) {
			mOnChangeListener.onChange(mDuration, progress, getRateOfProgress());
		}
		invalidate();
	}
	
	/**
	 * 得到进度条当前的值
	 * @return
	 */
	public int getProgress() {
		return mProgress;
	}
	
	/**
	 * 设置进度条背景的颜色
	 */
	public void setBackgroundColor( int color ) {
		mBackgroundColor = color;
	}
	
	/**
	 * 设置进度条进度的颜色
	 */
	public void setPrimaryColor( int color ) {
		mPrimaryColor = color;
	}
	
	/**
	 * 设置环形的宽度
	 * @param width
	 */
	public void setCircleWidth(float width) {
		mStrokeWidth = width;
		
	}

	@Override
	protected synchronized void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		
		int halfWidth = getWidth() / 2;
		int halfHeight = getHeight() /2;
		int radius = halfWidth < halfHeight ? halfWidth : halfHeight;
		float halfStrokeWidth = mStrokeWidth / 2;
		
		// 设置画笔
		mPaint.setColor(mBackgroundColor);
		mPaint.setDither(true);
		mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
		mPaint.setAntiAlias(true);
		mPaint.setStrokeWidth(mStrokeWidth);
		mPaint.setStyle(Paint.Style.STROKE);	//设置图形为空心
		
		// 画背景
		canvas.drawCircle(halfWidth, halfHeight, radius - halfStrokeWidth, mPaint);
		
		// 画当前进度的圆环
		mPaint.setColor(mPrimaryColor);	// 改变画笔颜色
		mRectF.top = halfHeight - radius + halfStrokeWidth;
		mRectF.bottom = halfHeight + radius - halfStrokeWidth;
		mRectF.left = halfWidth - radius + halfStrokeWidth;
		mRectF.right = halfWidth + radius - halfStrokeWidth;
		canvas.drawArc(mRectF, -90, getRateOfProgress() * 360, false, mPaint);
		canvas.save();
	}
	
	/**
	 * 得到当前的进度的比率
	 * <p> 用进度条当前的值 与 进度条的最大值求商 </p>
	 * @return
	 */
	private float getRateOfProgress() {
		return (float)mProgress / mDuration;
	}
	
}