安卓用canvas画曲线图

1.新建一个常变量类Constant.java

package com.rain.db;
import android.graphics.Point;

public class Constant {

	public static Point point;//获取屏幕的大小

}

　　

2.新建一个函数ChartView.java

 package com.rain.kongjian;

 import com.rain.db.Constant;

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

 public class ChartView extends View{
     public int XPoint=;    //原点的X坐标
     public int YPoint=Constant.point.y/;     //原点的Y坐标
     public int XScale=;     //X的刻度长度
     public int YScale=;     //Y的刻度长度
     public int XLength=Constant.point.x-;        //X轴的长度
     public int YLength=Constant.point.y/-;        //Y轴的长度
     public String[] XLabel;    //X的刻度
     public String[] YLabel;    //Y的刻度
     public String[] Data;      //数据
     public String Title;    //显示的标题
     public ChartView(Context context)
     {
         super(context);
     }
     public void SetInfo(String[] XLabels,String[] YLabels,String[] AllData,String strTitle)
     {
         XLabel=XLabels;
         YLabel=YLabels;
         Data=AllData;
         Title=strTitle;
         XScale=XLength/AllData.length;//实际X的刻度长度
         YScale=YLength/YLabels.length;
     }
     @Override
     protected void onDraw(Canvas canvas){
         super.onDraw(canvas);//重写onDraw方法

         //canvas.drawColor(Color.WHITE);//设置背景颜色
         Paint paint= new Paint();
         paint.setStyle(Paint.Style.STROKE);
         paint.setAntiAlias(true);//去锯齿
         paint.setColor(Color.BLACK);//颜色
         Paint paint1=new Paint();
         paint1.setStyle(Paint.Style.STROKE);
         paint1.setAntiAlias(true);//去锯齿
         paint1.setColor(Color.DKGRAY);
         paint.setTextSize();  //设置轴文字大小
         //设置Y轴
         canvas.drawLine(XPoint, YPoint-YLength, XPoint, YPoint, paint);   //轴线
         for(int i=;i*YScale<YLength ;i++)
         {
             canvas.drawLine(XPoint,YPoint-i*YScale, XPoint+, YPoint-i*YScale, paint);  //刻度
             try
             {
                 canvas.drawText(YLabel[i] , XPoint-, YPoint-i*YScale+, paint);  //文字
             }
             catch(Exception e)
             {
             }
         }
         canvas.drawLine(XPoint,YPoint-YLength,XPoint-,YPoint-YLength+,paint);  //箭头
         canvas.drawLine(XPoint,YPoint-YLength,XPoint+,YPoint-YLength+,paint);
         //设置字体的大小角度等
         paint.setTextSize();
         drawText(canvas,"单位:kWh", XPoint-, YPoint-YLength+YScale-, paint,-);

         //设置X轴
         paint.setTextSize();
         canvas.drawLine(XPoint,YPoint,XPoint+XLength,YPoint,paint);   //轴线
         for(int i=;i*XScale<XLength;i++)
         {
             canvas.drawLine(XPoint+i*XScale, YPoint, XPoint+i*XScale, YPoint-, paint);  //刻度
             try
             {
 //                canvas.drawText(XLabel[i], XPoint + i * XScale - 10,
 //                        YPoint + 20, paint); // 文字
                 drawText(canvas,XLabel[i], XPoint + i * XScale,
                         YPoint + , paint,-); // 文字
                 // 数据值
                 if (i >  && YCoord(Data[i - ]) != -
                         && YCoord(Data[i]) != -) // 保证有效数据
                     canvas.drawLine(XPoint + (i - ) * XScale,
                             YCoord(Data[i - ]), XPoint + i * XScale,
                             YCoord(Data[i]), paint);
                 canvas.drawCircle(XPoint + i * XScale, YCoord(Data[i]), ,
                         paint);
             } catch (Exception e) {
             }
         }
         canvas.drawLine(XPoint+XLength,YPoint,XPoint+XLength-,YPoint-,paint);    //箭头
         canvas.drawLine(XPoint+XLength,YPoint,XPoint+XLength-,YPoint+,paint);
         //设置标题位置
         paint.setTextSize();
         canvas.drawText(Title, XLength/-, , paint);
     }
     //设置文字显示方向
     void drawText(Canvas canvas ,String text , float x ,float y,Paint paint ,float angle){
         if(angle != ){
             canvas.rotate(angle, x, y);
         }
         canvas.drawText(text, x, y, paint);
         if(angle != ){
             canvas.rotate(-angle, x, y);
         }
     } 

     private int YCoord(String y0)  //计算绘制时的Y坐标，无数据时返回-999
     {
         int y;
         try
         {
             y=Integer.parseInt(y0);
         }
         catch(Exception e)
         {
             return -;    //出错则返回-999
         }
         try
         {
             return YPoint-y*YScale/Integer.parseInt(YLabel[]);
         }
         catch(Exception e)
         {
         }
         return y;
     }
 }

3.在需要的地方调用ChartView.java，这里在nibianqi_zt.java中调用

package com.example.myfragment;

import com.rain.kongjian.ChartView;

import com.rain.db.Constant;

import android.app.ActionBar;
import android.app.Activity;
import android.os.Bundle;
import android.view.MenuItem;

public class nibianqi_zt extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.nibianqi_zt);        

        /* 显示App icon左侧的back键 */
        ActionBar actionBar = getActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);

　　　　 Constant.point = new Point();        
　　　　 getWindowManager().getDefaultDisplay().getSize(Constant.point);//获取屏幕分辨率

        ChartView myView=new ChartView(this);
        setContentView(myView);
        myView.SetInfo(new String[] { "7-11", "7-12", "7-13", "7-14", "7-15",
                "7-16", "7-17" }, // X轴刻度
                new String[] { "", "", "", "", "", "" }, // Y轴刻度
                new String[] { "", "", "", "", "", "", "" }, // 数据
                "图标的标题");

    }

    // 顶部返回键
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case android.R.id.home:
            finish();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

}

效果演示如下：