Android编程实现canvas绘制柱状统计图功能【自动计算宽高及分度值、可左右滑动】

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

这里实现了一个简单的柱状统计图，如下：

 

特点：

1.根据数据源自动计算每个条目的高度、宽度、间距，自动计算分度值。

2.当条目数较多时，可左右滑动查看全部内容，图形、文字同步滑动，并且松手后会渐渐的停下来（而不是立刻停下来）。

代码：

（1）核心代码：barChartVIEw.Java

package com.sina.appbarchart;import androID.app.Activity;import androID.content.Context;import androID.graphics.Bitmap;import androID.graphics.BitmapFactory;import androID.graphics.Canvas;import androID.graphics.color;import androID.graphics.Paint;import androID.graphics.Path;import androID.graphics.Rect;import androID.support.annotation.NonNull;import androID.support.v7.app.Actionbar;import androID.support.v7.app.ActionBaractivity;import androID.util.AttributeSet;import androID.vIEw.MotionEvent;import androID.vIEw.VIEw;/** * 自定义组件：条形统计图 * Created by hanj on 14-12-30. */public class barChartVIEw extends VIEw { private int screenW,screenH; private barChartItemBean[] mItems; //max value in mItems. private float maxValue; //max height of the bar private int maxHeight; private int[] mbarcolors = new int[]{color.RED,color.GREEN,color.BLUE,color.YELLOW,color.magenta,color.CYAN}; private Paint barPaint,linePaint,textPaint; private Rect barRect,leftWhiteRect,rightWhiteRect; private Path textPath; private int leftmargin,topmargin,smallmargin; //the wIDth of one bar item private int barItemWIDth; //the spacing between two bar items. private int barSpace; //the wIDth of the line. private int linestrokeWIDth; /**  * The x-position of y-index and the y-position of the x-index..  */ private float x_index_startY,y_index_startX; private Bitmap arrowBmp; private Rect x_index_arrowRect,y_index_arrowRect; private static final int BG_color = color.parsecolor("#E5E5E5"); public barChartVIEw(Context context,AttributeSet attrs) {  super(context,attrs);  init(context); } private voID init(Context context) {  screenW = ScreenUtils.getScreenW(context);  screenH = ScreenUtils.getScreenH(context);  leftmargin = ScreenUtils.dp2px(context,16);  topmargin = ScreenUtils.dp2px(context,40);  smallmargin = ScreenUtils.dp2px(context,6);  barPaint = new Paint();  barPaint.setcolor(mbarcolors[0]);  linePaint = new Paint();  linestrokeWIDth = ScreenUtils.dp2px(context,1);  linePaint.setstrokeWIDth(linestrokeWIDth);  textPaint = new Paint();  textPaint.setAntiAlias(true);  barRect = new Rect(0,0);  textPath = new Path();  leftWhiteRect = new Rect(0,screenH);  rightWhiteRect = new Rect(screenW - leftmargin,screenW,screenH);  arrowBmp = BitmapFactory.decodeResource(context.getResources(),R.drawable.arrow_up); } //标记是否已经获取过状态拉的高度 private boolean statusHeightHasGet; @OverrIDe protected voID onDraw(Canvas canvas) {  super.onDraw(canvas);  if (!statusHeightHasGet) {   subStatusbarHeight();   statusHeightHasGet = true;  }  //draw background  canvas.drawcolor(BG_color);  //bounds  checkleftMoving();  textPaint.setTextSize(ScreenUtils.dp2px(getContext(),16));  for (int i = 0; i < mItems.length; i++) {   //draw bar rect   barRect.left = (int) y_index_startX + barItemWIDth * i + barSpace * (i + 1) - (int) leftMoving;   barRect.top = topmargin * 2 + (int) (maxHeight * (1.0f - mItems[i].itemValue / maxValue));   barRect.right = barRect.left + barItemWIDth;   barPaint.setcolor(mbarcolors[i % mbarcolors.length]);   canvas.drawRect(barRect,barPaint);   //draw type text   String typeText = mItems[i].itemType;   float textPathStartX = barRect.left + barItemWIDth / 2 -     (float) (Math.sin(Math.PI / 6)) * textPaint.measureText("好") / 2;   float textPathStartY = barRect.bottom;   textPath.reset();   textPath.moveto(textPathStartX,textPathStartY);   textPath.lineto(textPathStartX + (float) (1000 * Math.tan(Math.PI / 6)),textPathStartY + 1000);   canvas.drawTextOnPath(typeText,textPath,smallmargin * 1.5f,smallmargin * 2,textPaint);   //draw value text   String valueText = String.valueOf(mItems[i].itemValue);   canvas.drawText(valueText,barRect.left - (textPaint.measureText(valueText) - barItemWIDth) / 2,barRect.top - smallmargin,textPaint);  }  //draw left white space and right white space  int c = barPaint.getcolor();  barPaint.setcolor(BG_color);  leftWhiteRect.right = (int) y_index_startX;  canvas.drawRect(leftWhiteRect,barPaint);  canvas.drawRect(rightWhiteRect,barPaint);  barPaint.setcolor(c);  //draw x-index line.  canvas.drawline(    y_index_startX - linestrokeWIDth / 2,x_index_startY,screenW - leftmargin,linePaint);  //draw y-index line.  canvas.drawline(    y_index_startX,x_index_startY + linestrokeWIDth / 2,y_index_startX,topmargin / 2,linePaint);  canvas.drawBitmap(arrowBmp,null,y_index_arrowRect,null);  canvas.save();  canvas.rotate(90,(x_index_arrowRect.left + x_index_arrowRect.right) / 2,(x_index_arrowRect.top + x_index_arrowRect.bottom) / 2);  canvas.drawBitmap(arrowBmp,x_index_arrowRect,null);  canvas.restore();  //draw division value  int maxdivisionValueHeight = (int) (maxHeight * 1.0f / maxValue * maxdivisionValue);  textPaint.setTextSize(ScreenUtils.dp2px(getContext(),10));  for (int i = 1; i <= 10; i++) {   float startY = barRect.bottom - maxdivisionValueHeight * 0.1f * i;   if (startY < topmargin / 2) {    break;   }   canvas.drawline(y_index_startX,startY,y_index_startX + 10,linePaint);   String text = String.valueOf(maxdivisionValue * 0.1f * i);   canvas.drawText(text,y_index_startX - textPaint.measureText(text) - 5,startY + textPaint.measureText("0") / 2,textPaint);  } } private float leftMoving; private float lastPointX; private float movingleftThisTime = 0.0f; @OverrIDe public boolean ontouchEvent(@NonNull MotionEvent event) {  int type = event.getAction();  switch (type) {   case MotionEvent.ACTION_DOWN:    lastPointX = event.getRawX();    break;   case MotionEvent.ACTION_MOVE:    float x = event.getRawX();    movingleftThisTime = lastPointX - x;    leftMoving += movingleftThisTime;    lastPointX = x;    invalIDate();    break;   case MotionEvent.ACTION_UP:    //smooth scroll    new Thread(new SmoothScrollThread(movingleftThisTime)).start();    break;   default:    return super.ontouchEvent(event);  }  return true; } /**  * Check the value of leftMoving to ensure that the vIEw is not out of the screen.  */ private voID checkleftMoving() {  if (leftMoving < 0) {   leftMoving = 0;  }  if (leftMoving > (maxRight - minRight)) {   leftMoving = maxRight - minRight;  } } public barChartItemBean[] getItems() {  return mItems; } public voID setItems(barChartItemBean[] items) {  if (items == null) {   throw new RuntimeException("barChartVIEw.setItems(): the param items cannot be null.");  }  if (items.length == 0) {   return;  }  this.mItems = items;  //Calculate the max value.  maxValue = items[0].itemValue;  for (barChartItemBean bean : items) {   if (bean.itemValue > maxValue) {    maxValue = bean.itemValue;   }  }  //Calculate the max division value.  getRange(maxValue,0);  //Get the wIDth of each bar.  getbarItemWIDth(screenW,items.length);  //Refresh the vIEw.  invalIDate(); } private int maxRight,minRight; /**  * Get the wIDth of each bar which is depended on the screenW and item count.  */ private voID getbarItemWIDth(int screenW,int itemCount) {  //The min wIDth of the bar is 50dp.  int minbarWIDth = ScreenUtils.dp2px(getContext(),40);  //The min wIDth of spacing.  int minbarSpacing = ScreenUtils.dp2px(getContext(),30);  barItemWIDth = (screenW - leftmargin * 2) / (itemCount + 3);  barSpace = (screenW - leftmargin * 2 - barItemWIDth * itemCount) / (itemCount + 1);  if (barItemWIDth < minbarWIDth || barSpace < minbarSpacing) {   barItemWIDth = minbarWIDth;   barSpace = minbarSpacing;  }  maxRight = (int) y_index_startX + linestrokeWIDth + (barSpace + barItemWIDth) * mItems.length;  minRight = screenW - leftmargin - barSpace; } /**  * Sub the height of status bar and action bar to get the accurate height of screen.  */ private voID subStatusbarHeight() {  //The height of the status bar  int statusHeight = ScreenUtils.getStatusbarHeight((Activity) getContext());  //The height of the actionbar  Actionbar ab = ((ActionBaractivity) getContext()).getSupportActionbar();  int abHeight = ab == null ? 0 : ab.getHeight();  screenH -= (statusHeight + abHeight);  barRect.top = topmargin * 2;  barRect.bottom = screenH - topmargin * 3;  maxHeight = barRect.bottom - barRect.top;  x_index_startY = barRect.bottom;  x_index_arrowRect = new Rect(screenW - leftmargin,(int) (x_index_startY - 10),screenW - leftmargin + 10,(int) (x_index_startY + 10)); } //The max and min division value. private float maxdivisionValue,mindivisionValue; //Get the max and min division value by the max and min value in mItems. private voID getRange(float maxValue,float minValue) {  //max  int scale = Utility.getScale(maxValue);  float unscaledValue = (float) (maxValue / Math.pow(10,scale));  maxdivisionValue = (float) (getRangetop(unscaledValue) * Math.pow(10,scale));  y_index_startX = getdivisionTextMaxWIDth(maxdivisionValue) + 10;  y_index_arrowRect = new Rect((int) (y_index_startX - 5),topmargin / 2 - 20,(int) (y_index_startX + 5),topmargin / 2); } private float getRangetop(float value) {  //value: [1,10)  if (value < 1.2) {   return 1.2f;  }  if (value < 1.5) {   return 1.5f;  }  if (value < 2.0) {   return 2.0f;  }  if (value < 3.0) {   return 3.0f;  }  if (value < 4.0) {   return 4.0f;  }  if (value < 5.0) {   return 5.0f;  }  if (value < 6.0) {   return 6.0f;  }  if (value < 8.0) {   return 8.0f;  }  return 10.0f; } /**  * Get the max wIDth of the division value text.  */ private float getdivisionTextMaxWIDth(float maxdivisionValue) {  Paint textPaint = new Paint();  textPaint.setTextSize(ScreenUtils.dp2px(getContext(),10));  float max = textPaint.measureText(String.valueOf(maxdivisionValue * 0.1f));  for (int i = 2; i <= 10; i++) {   float w = textPaint.measureText(String.valueOf(maxdivisionValue * 0.1f * i));   if (w > max) {    max = w;   }  }  return max; } /**  * Use this thread to create a smooth scroll after ACTION_UP.  */ private class SmoothScrollThread implements Runnable {  float lastMoving;  boolean scrolling = true;  private SmoothScrollThread(float lastMoving) {   this.lastMoving = lastMoving;   scrolling = true;  }  @OverrIDe  public voID run() {   while (scrolling) {    long start = System.currentTimeMillis();    lastMoving = (int) (0.9f * lastMoving);    leftMoving += lastMoving;    checkleftMoving();    postInvalIDate();    if (Math.abs(lastMoving) < 5) {     scrolling = false;    }    long end = System.currentTimeMillis();    if (end - start < 20) {     try {      Thread.sleep(20 - (end - start));     } catch (InterruptedException e) {      e.printstacktrace();     }    }   }  } } /**  * A model class to keep the bar item info.  */ static class barChartItemBean {  private String itemType;  private float itemValue;  public barChartItemBean(String itemType,float itemValue) {   this.itemType = itemType;   this.itemValue = itemValue;  } }}

（2）该自定义组件的使用：

package com.sina.appbarchart;import androID.support.v7.app.ActionBaractivity;import androID.os.Bundle;public class MainActivity extends ActionBaractivity { @OverrIDe protected voID onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentVIEw(R.layout.activity_main);  barChartVIEw barChartVIEw = (barChartVIEw) findVIEwByID(R.ID.bar_chart);  barChartVIEw.barChartItemBean[] items = new barChartVIEw.barChartItemBean[]{    new barChartVIEw.barChartItemBean("餐饮",300),new barChartVIEw.barChartItemBean("学习",200),new barChartVIEw.barChartItemBean("旅行",270),new barChartVIEw.barChartItemBean("购物",110),new barChartVIEw.barChartItemBean("人际关系",120),new barChartVIEw.barChartItemBean("娱乐",80),new barChartVIEw.barChartItemBean("投资",new barChartVIEw.barChartItemBean("教育",280)  };  barChartVIEw.setItems(items); }}

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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