這裡畫了個餅圖的變種，具有分割突出效果的餅圖(Pie Chart)，就是個切蛋糕效果的餅圖，畫這種圖，其技巧就在於圓心的偏移。

在圓心偏移，半徑不變的基礎上，效果就出來了。

    上圖:

     怎麼樣，效果還是有模有樣的吧。

     程式碼很簡單，附上:

package com.xcl.chart;


/**
 * Canvas練習 
 * 	  自已繪分割突出效果的餅圖(Pie 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 PanelPieChart2 extends View{
	
	private int ScrWidth,ScrHeight;	
	
	 //演示用的百分比例,實際使用中，即為外部傳入的比例引數  
	private final float arrPer[] = new float[]{20f,30f,10f,40f};  
	//RGB顏色陣列
	private final int arrColorRgb[][] = { {77, 83, 97},  
							              {148, 159, 181},  
							              {253, 180, 90},
							              {52, 194, 188}} ;
	 //指定突出哪個塊
	private final int offsetBlock = 2;
	
public PanelPieChart2(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		
		//螢幕資訊
		DisplayMetrics dm = getResources().getDisplayMetrics();
		ScrHeight = dm.heightPixels;
		ScrWidth = dm.widthPixels;
	}

	
	public void onDraw(Canvas canvas){
		//畫布背景
		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);   
        
        //畫筆初始化
		Paint PaintArc = new Paint();  		
		Paint PaintLabel = new Paint();  
		PaintLabel.setColor(Color.WHITE);
		PaintLabel.setTextSize(16);          
                
        //位置計算類  
        XChartCalc xcalc = new XChartCalc();	
		
        float Percentage = 0.0f;
 		float CurrPer = 0.0f;
		int i= 0;  
        for(i=0; i<arrPer.length; i++)   
        {  
            //將百分比轉換為餅圖顯示角度  
            Percentage = 360 * (arrPer[i]/ 100);  
            Percentage = (float)(Math.round(Percentage *100))/100;  
            //分配顏色            
            PaintArc.setARGB(255,arrColorRgb[i][0], arrColorRgb[i][1], arrColorRgb[i][2]);
               
            
            if( i == offsetBlock) //指定突出哪個塊
            {
            	//偏移圓心點位置
            	float newRadius = radius /10;
            	 //計算百分比標籤
	            xcalc.CalcArcEndPointXY(cirX, cirY, newRadius , CurrPer + Percentage/2); 	
	            
	            arcLeft = xcalc.getPosX() - radius;  
	            arcTop  = xcalc.getPosY() - radius ;  
	            arcRight = xcalc.getPosX() + radius ;  
	            arcBottom = xcalc.getPosY() + radius ;  
	            RectF arcRF1 = new RectF(arcLeft ,arcTop,arcRight,arcBottom);   
	            
	          //在餅圖中顯示所佔比例  
	            canvas.drawArc(arcRF1, CurrPer, Percentage, true, PaintArc);     
	            
	            //計算百分比標籤
	            xcalc.CalcArcEndPointXY(xcalc.getPosX(), xcalc.getPosY(), radius - radius/2/2, CurrPer + Percentage/2); 	
				//標識
			    canvas.drawText(Float.toString(arrPer[i])+"%",xcalc.getPosX(), xcalc.getPosY() ,PaintLabel);	
			    
	            
            }else{
	            //在餅圖中顯示所佔比例  
	            canvas.drawArc(arcRF0, CurrPer, Percentage, true, PaintArc);                 
	            //計算百分比標籤
	            xcalc.CalcArcEndPointXY(cirX, cirY, radius - radius/2/2, CurrPer + Percentage/2); 	
				//標識
			    canvas.drawText(Float.toString(arrPer[i])+"%",xcalc.getPosX(), xcalc.getPosY() ,PaintLabel);		
		    
            }
            
            //下次的起始角度  
            CurrPer += Percentage;  
        }  
          
	}

}
 

附上我其它繪製的圖連結:

MAIL: [email protected]

BLOG: http://blog.csdn.net/xcl168