Android编程实现canvas绘制饼状统计图功能示例【自动适应条目数量与大小】

概述本文实例讲述了Android编程实现canvas绘制饼状统计图功能。分享给大家供大家参考，具体如下：

本文实例讲述了AndroID编程实现canvas绘制饼状统计图功能。分享给大家供大家参考，具体如下：

本例的目的是实现一个简单的饼状统计图，效果如下：

 

 

特点：

1.使用非常方便，可放在xml布局文件中，然后在代码中设置内容，即：

PIEChartVIEw pIEChartVIEw = (PIEChartVIEw) findVIEwByID(R.ID.pIE_chart);PIEChartVIEw.PIEItemBean[] items = new PIEChartVIEw.PIEItemBean[]{    new PIEChartVIEw.PIEItemBean("娱乐",200),new PIEChartVIEw.PIEItemBean("旅行",100),new PIEChartVIEw.PIEItemBean("学习",120),new PIEChartVIEw.PIEItemBean("人际关系",160),new PIEChartVIEw.PIEItemBean("交通",new PIEChartVIEw.PIEItemBean("餐饮",480)};pIEChartVIEw.setPIEItems(items);

2.条目数量，大小及折线位置，长度均自适应。左侧条目往左侧划线，右侧条目往右侧划线，文字描述与百分比居中对齐，并且文字“下划线”与文字长度自适应。对于很小的条目，将自动将折线延长以尽可能避免文字遮盖

核心代码：PIEChartVIEw.Java:

public class PIEChartVIEw extends VIEw {  private int screenW,screenH;  /**   * The paint to draw text,pIE and line.   */  private Paint textPaint,pIEPaint,linePaint;  /**   * The center and the radius of the pIE.   */  private int pIECenterX,pIECenterY,pIERadius;  /**   * The oval to draw the oval in.   */  private RectF pIEoval;  private float smallmargin;  private int[] mPIEcolors = new int[]{color.RED,color.GREEN,color.BLUE,color.YELLOW,color.magenta,color.CYAN};  private PIEItemBean[] mPIEItems;  private float totalValue;  public PIEChartVIEw(Context context) {    super(context);    init(context);  }  public PIEChartVIEw(Context context,AttributeSet attrs) {    super(context,attrs);    init(context);  }  public PIEChartVIEw(Context context,AttributeSet attrs,int defStyleAttr) {    super(context,attrs,defStyleAttr);    init(context);  }  private voID init(Context context) {    //init screen    screenW = ScreenUtils.getScreenW(context);    screenH = ScreenUtils.getScreenH(context);    pIECenterX = screenW / 2;    pIECenterY = screenH / 3;    pIERadius = screenW / 4;    smallmargin = ScreenUtils.dp2px(context,5);    pIEoval = new RectF();    pIEoval.left = pIECenterX - pIERadius;    pIEoval.top = pIECenterY - pIERadius;    pIEoval.right = pIECenterX + pIERadius;    pIEoval.bottom = pIECenterY + pIERadius;    //The paint to draw text.    textPaint = new Paint();    textPaint.setAntiAlias(true);    textPaint.setTextSize(ScreenUtils.dp2px(context,16));    //The paint to draw circle.    pIEPaint = new Paint();    pIEPaint.setAntiAlias(true);    pIEPaint.setStyle(Paint.Style.FILL);    //The paint to draw line to show the concrete text    linePaint = new Paint();    linePaint.setAntiAlias(true);    linePaint.setstrokeWIDth(ScreenUtils.dp2px(context,1));  }  //The degree position of the last item arc's center.  private float lastDegree = 0;  //The count of the continues 'small' item.  private int addTimes = 0;  @OverrIDe  protected voID onDraw(Canvas canvas) {    super.onDraw(canvas);    if (mPIEItems != null && mPIEItems.length > 0) {      float start = 0.0f;      for (int i = 0; i < mPIEItems.length; i++) {        //draw pIE        pIEPaint.setcolor(mPIEcolors[i % mPIEcolors.length]);        float sweep = mPIEItems[i].getItemValue() / totalValue * 360;        canvas.drawArc(pIEoval,start,sweep,true,pIEPaint);        //draw line away from the pIE        float radians = (float) ((start + sweep / 2) / 180 * Math.PI);        float linestartX = pIECenterX + pIERadius * 0.7f * (float) (Math.cos(radians));        float linestartY = pIECenterY + pIERadius * 0.7f * (float) (Math.sin(radians));        float linestopX,linestopY;        float rate;        if (getoffset(start + sweep / 2) > 60) {          rate = 1.3f;        } else if (getoffset(start + sweep / 2) > 30) {          rate = 1.2f;        } else {          rate = 1.1f;        }        //If the item is very small,make the text further away from the pIE to avoID being hIDed by other text.        if (start + sweep / 2 - lastDegree < 30) {          addTimes++;          rate += 0.2f * addTimes;        } else {          addTimes = 0;        }        linestopX = pIECenterX + pIERadius * rate * (float) (Math.cos(radians));        linestopY = pIECenterY + pIERadius * rate * (float) (Math.sin(radians));        canvas.drawline(linestartX,linestartY,linestopX,linestopY,linePaint);        //write text        String itemTypeText = mPIEItems[i].getItemType();        String itemPercentText = Utility.formatfloat(mPIEItems[i].getItemValue() / totalValue * 100) + "%";        float itemTypeTextLen = textPaint.measureText(itemTypeText);        float itemPercentTextLen = textPaint.measureText(itemPercentText);        float lineTextWIDth = Math.max(itemTypeTextLen,itemPercentTextLen);        float textStartX = linestopX;        float textStartY = linestopY - smallmargin;        float percentStartX = linestopX;        float percentStartY = linestopY + textPaint.getTextSize();        if (linestartX > pIECenterX) {          textStartX += (smallmargin + Math.abs(itemTypeTextLen - lineTextWIDth) / 2);          percentStartX += (smallmargin + Math.abs(itemPercentTextLen - lineTextWIDth) / 2);        } else {          textStartX -= (smallmargin + lineTextWIDth - Math.abs(itemTypeTextLen - lineTextWIDth) / 2);          percentStartX -= (smallmargin + lineTextWIDth - Math.abs(itemPercentTextLen - lineTextWIDth) / 2);        }        canvas.drawText(itemTypeText,textStartX,textStartY,textPaint);        //draw percent text        canvas.drawText(itemPercentText,percentStartX,percentStartY,textPaint);        //draw text underline        float textlinestopX = linestopX;        if (linestartX > pIECenterX) {          textlinestopX += (lineTextWIDth + smallmargin * 2);        } else {          textlinestopX -= (lineTextWIDth + smallmargin * 2);        }        canvas.drawline(linestopX,textlinestopX,linePaint);        lastDegree = start + sweep / 2;        start += sweep;      }    }  }  public PIEItemBean[] getPIEItems() {    return mPIEItems;  }  public voID setPIEItems(PIEItemBean[] pIEItems) {    this.mPIEItems = pIEItems;    totalValue = 0;    for (PIEItemBean item : mPIEItems) {      totalValue += item.getItemValue();    }    invalIDate();  }  private float getoffset(float radius) {    int a = (int) (radius % 360 / 90);    switch (a) {      case 0:        return radius;      case 1:        return 180 - radius;      case 2:        return radius - 180;      case 3:        return 360 - radius;    }    return radius;  }  static class PIEItemBean {    private String itemType;    private float itemValue;    PIEItemBean(String itemType,float itemValue) {      this.itemType = itemType;      this.itemValue = itemValue;    }    public String getItemType() {      return itemType;    }    public voID setItemType(String itemType) {      this.itemType = itemType;    }    public float getItemValue() {      return itemValue;    }    public voID setItemValue(float itemValue) {      this.itemValue = itemValue;    }  }}

完整实例代码点击此处本站下载。

更多关于AndroID相关内容感兴趣的读者可查看本站专题：《Android图形与图像处理技巧总结》、《Android开发入门与进阶教程》、《Android调试技巧与常见问题解决方法汇总》、《Android基本组件用法总结》、《Android视图View技巧总结》、《Android布局layout技巧总结》及《Android控件用法总结》

希望本文所述对大家AndroID程序设计有所帮助。

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