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：