安卓用canvas畫曲線圖

1.新建一個常變量類Constant.java

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

public class Constant {
	
	public static Point point;//獲取屏幕的大小
	
}

　　

2.新建一個函數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=40;    //原點的X坐標
    public int YPoint=Constant.point.y/2;     //原點的Y坐標
    public int XScale=55;     //X的刻度長度
    public int YScale=40;     //Y的刻度長度
    public int XLength=Constant.point.x-100;        //X軸的長度
    public int YLength=Constant.point.y/2-100;        //Y軸的長度
    public String[] XLabel;    //X的刻度
    public String[] YLabel;    //Y的刻度
    public String[] Data;      //數據
    public String Title;    //顯示的標題
    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;//實際X的刻度長度
        YScale=YLength/YLabels.length;
    }
    @Override
    protected void onDraw(Canvas canvas){
        super.onDraw(canvas);//重寫onDraw方法

        //canvas.drawColor(Color.WHITE);//設置背景顏色
        Paint paint= new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setAntiAlias(true);//去鋸齒
        paint.setColor(Color.BLACK);//顏色
        Paint paint1=new Paint();
        paint1.setStyle(Paint.Style.STROKE);
        paint1.setAntiAlias(true);//去鋸齒
        paint1.setColor(Color.DKGRAY);
        paint.setTextSize(12);  //設置軸文字大小
        //設置Y軸
        canvas.drawLine(XPoint, YPoint-YLength, XPoint, YPoint, paint);   //軸線
        for(int i=0;i*YScale<YLength ;i++)               
        {
            canvas.drawLine(XPoint,YPoint-i*YScale, XPoint+5, YPoint-i*YScale, paint);  //刻度
            try
            {
                canvas.drawText(YLabel[i] , XPoint-30, YPoint-i*YScale+5, paint);  //文字
            }
            catch(Exception e)
            {
            }
        }
        canvas.drawLine(XPoint,YPoint-YLength,XPoint-3,YPoint-YLength+6,paint);  //箭頭
        canvas.drawLine(XPoint,YPoint-YLength,XPoint+3,YPoint-YLength+6,paint);
        //設置字體的大小角度等
        paint.setTextSize(20);
        drawText(canvas,"單位:kWh", XPoint-5, YPoint-YLength+YScale-5, paint,-90);
        
        //設置X軸
        paint.setTextSize(12);
        canvas.drawLine(XPoint,YPoint,XPoint+XLength,YPoint,paint);   //軸線
        for(int i=0;i*XScale<XLength;i++)   
        {
            canvas.drawLine(XPoint+i*XScale, YPoint, XPoint+i*XScale, YPoint-5, 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 + 40, paint,-45); // 文字
                // 數據值
                if (i > 0 && YCoord(Data[i - 1]) != -999
                        && YCoord(Data[i]) != -999) // 保證有效數據
                    canvas.drawLine(XPoint + (i - 1) * XScale,
                            YCoord(Data[i - 1]), XPoint + i * XScale,
                            YCoord(Data[i]), paint);
                canvas.drawCircle(XPoint + i * XScale, YCoord(Data[i]), 2,
                        paint);
            } catch (Exception e) {
            }
        }
        canvas.drawLine(XPoint+XLength,YPoint,XPoint+XLength-6,YPoint-3,paint);    //箭頭
        canvas.drawLine(XPoint+XLength,YPoint,XPoint+XLength-6,YPoint+3,paint); 
        //設置標題位置
        paint.setTextSize(28);
        canvas.drawText(Title, XLength/2-28, 50, paint);
    }
    //設置文字顯示方向
    void drawText(Canvas canvas ,String text , float x ,float y,Paint paint ,float angle){  
        if(angle != 0){  
            canvas.rotate(angle, x, y);   
        }  
        canvas.drawText(text, x, y, paint);  
        if(angle != 0){  
            canvas.rotate(-angle, x, y);   
        }  
    } 
    
    private int YCoord(String y0)  //計算繪制時的Y坐標，無數據時返回-999
    {
        int y;
        try
        {
            y=Integer.parseInt(y0);
        }
        catch(Exception e)
        {
            return -999;    //出錯則返回-999
        }
        try
        {
            return YPoint-y*YScale/Integer.parseInt(YLabel[1]);
        }
        catch(Exception e)
        {
        }
        return y;
    }
}

3.在需要的地方調用ChartView.java，這里在nibianqi_zt.java中調用

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);        

        /* 顯示App icon左側的back鍵 */
        ActionBar actionBar = getActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);

　　　　 Constant.point = new Point();        
　　　　 getWindowManager().getDefaultDisplay().getSize(Constant.point);//獲取屏幕分辨率
                
        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軸刻度
                new String[] { "", "50", "100", "150", "200", "250" }, // Y軸刻度
                new String[] { "15", "23", "10", "36", "45", "40", "12" }, // 數據
                "圖標的標題");

    }

    // 頂部返回鍵
    @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：