Android Canvas练习(8)自已绘环形图(Dount Chart)

    继续常规图的绘制研究，在这绘制了个环形图(Dount Chart),很简单，大圆套小圆就出来了。呵呵，照例先上猛照:

       

         怎么样，效果还可以吧，实现代码很少，附上:         

package com.xcl.chart;

/**
 * Canvas练习 
 * 	  自已画环形图(Dount Chart)
 *     
 * author:xiongchuanliang
 * date:2014-4-12
 */

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.DisplayMetrics;
import android.view.View;

public class PanelDountChart2 extends View{
	
	private int ScrWidth,ScrHeight;	
	
	 //演示用的百分比例,实际使用中，即为外部传入的比例参数  
	private final float arrPer[] = new float[]{20f,30f,10f,40f};  
	//RGB颜色数组
	private final int arrColorRgb[][] = { {77, 83, 97},  
							              {148, 159, 181},  
							              {253, 180, 90},
							              {52, 194, 188}} ;
	
	
public PanelDountChart2(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		
		//屏幕信息
		DisplayMetrics dm = getResources().getDisplayMetrics();
		ScrHeight = dm.heightPixels;
		ScrWidth = dm.widthPixels;
	}

	
	public void onDraw(Canvas canvas){
		//画布背景
		canvas.drawColor(Color.WHITE);		          
          
        float cirX = ScrWidth / 2;  
        float cirY = ScrHeight / 3 ;  
        float radius = ScrHeight / 5 ;//150;  
                                  
        float arcLeft = cirX - radius;  
        float arcTop  = cirY - radius ;  
        float arcRight = cirX + radius ;  
        float arcBottom = cirY + radius ;  
        RectF arcRF0 = new RectF(arcLeft ,arcTop,arcRight,arcBottom);   
        
        //画笔初始化
		Paint PaintArc = new Paint();  	
		PaintArc.setAntiAlias(true);
		
		Paint PaintLabel = new Paint();  		
		PaintLabel.setTextSize(22);      
		canvas.drawText("author:xiongchuanliang", 50, ScrHeight - 280, PaintLabel); 	
		PaintLabel.setColor(Color.WHITE);
		PaintLabel.setTextSize(16); 
                
        //位置计算类  
        XChartCalc xcalc = new XChartCalc();	
		
        float Percentage = 0.0f;
 		float CurrPer = 0.0f;
		int i= 0;  
        for(i=0; i<arrPer.length; i++)   
        {  
            //将百分比转换为饼图显示角度  
            Percentage = 360 * (arrPer[i]/ 100);  
            Percentage = (float)(Math.round(Percentage *100))/100;  
            //分配颜色            
            PaintArc.setARGB(255,arrColorRgb[i][0], arrColorRgb[i][1], arrColorRgb[i][2]);
               
            //在饼图中显示所占比例  
            canvas.drawArc(arcRF0, CurrPer, Percentage, true, PaintArc);                 
            //计算百分比标签
            xcalc.CalcArcEndPointXY(cirX, cirY, radius - radius/2/2, CurrPer + Percentage/2); 	
			//标识
		    canvas.drawText(Float.toString(arrPer[i])+"%",xcalc.getPosX(), xcalc.getPosY() ,PaintLabel);		    
            //下次的起始角度  
            CurrPer += Percentage;  
        }  
                         
        //画圆心
        PaintArc.setColor(Color.WHITE);
        canvas.drawCircle(cirX,cirY,radius/2,PaintArc);  
        	
	}

	
}

     就这很么点代码就搞定了。 所以说简单的图完全可以不用图表库的。

    代码中用到的类，在我前面的例子中找即可。

   Android Canvas练习(1)画一张报表来玩   

   Android Canvas练习(2)自已绘饼图

   Android Canvas练习(3)自已绘柱形图

   Android Canvas练习(4)自已绘折线图

     Android Canvas练习(5)自已绘面积图(Area Chart)

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