Android编程开发之在Canvas中利用Path绘制基本图形(圆形,矩形,椭圆,三角形等)

本文实例讲述了android编程开发之在canvas中利用path绘制基本图形的方法。分享给大家供大家参考，具体如下：

在android中绘制基本的集合图形，本程序就是自定义一个view组件，程序重写该view组件的ondraw(canvase)方法，然后在该canvas上绘制大量的基本的集合图形。

直接上代码：

1.自定义的view组件代码：

package com.infy.configuration;
import android.content.context;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.lineargradient;
import android.graphics.paint;
import android.graphics.path;
import android.graphics.rectf;
import android.graphics.shader;
import android.util.attributeset;
import android.view.view;
public class myview extends view{
    public myview(context context, attributeset attrs) {
      super(context, attrs);
    }
    @override
    protected void ondraw(canvas canvas) {
      // todo auto-generated method stub
      super.ondraw(canvas);
      //把整张画布绘制成白色
      canvas.drawcolor(color.white);
      paint paint = new paint();
      //去锯齿
      paint.setantialias(true);
      paint.setcolor(color.blue);
      paint.setstyle(paint.style.stroke);
      paint.setstrokewidth(3);
      //绘制圆形
      canvas.drawcircle(40, 40, 30, paint);
      //绘制正方形
      canvas.drawrect(10, 80, 70, 140, paint);
      //绘制矩形
      canvas.drawrect(10, 150, 70, 190, paint);
      rectf rel = new rectf(10,240,70,270);
      //绘制椭圆
      canvas.drawoval(rel, paint);
      //定义一个path对象，封闭一个三角形
      path path1 = new path();
      path1.moveto(10, 340);
      path1.lineto(70, 340);
      path1.lineto(40, 290);
      path1.close();
      //根据path进行绘制，绘制三角形
      canvas.drawpath(path1, paint);
      //定义一个path对象，封闭一个五角星
      path path2 = new path();
      path2.moveto(27, 360);
      path2.lineto(54, 360);
      path2.lineto(70, 392);
      path2.lineto(40, 420);
      path2.lineto(10, 392);
      path2.close();
      //根据path进行绘制，绘制五角星
      canvas.drawpath(path2, paint);
      //设置填丛风格后进行绘制
      paint.setstyle(paint.style.fill);
      paint.setcolor(color.red);
      canvas.drawcircle(120, 40, 30, paint);
      //绘制正方形
      canvas.drawrect(90, 80, 150, 140, paint);
      //绘制矩形
      canvas.drawrect(90, 150, 150, 190, paint);
      //绘制圆角矩形
      rectf re2 = new rectf(90,200,150,230);
      canvas.drawroundrect(re2, 15, 15, paint);
      //绘制椭圆
      rectf re21 = new rectf(90, 240, 150, 270);
      canvas.drawoval(re21, paint);
      path path3 = new path();
      path3.moveto(90, 340);
      path3.lineto(150, 340);
      path3.lineto(120, 290);
      path3.close();
      //绘制三角形
      canvas.drawpath(path3,paint);
      //绘制五角形
      path path4 = new path();
      path4.moveto(106, 360);
      path4.lineto(134, 360);
      path4.lineto(150, 392);
      path4.lineto(120, 420);
      path4.lineto(90, 392);
      path4.close();
      canvas.drawpath(path4, paint);
      //设置渐变器后绘制
      //为paint设置渐变器
      shader mshasder = new lineargradient(0, 0, 40, 60, new int[]{color.red,color.green,color.blue,color.yellow}, null, shader.tilemode.repeat);
      paint.setshader(mshasder);
      //设置阴影
      paint.setshadowlayer(45, 10, 10, color.gray);
      //绘制圆形
      canvas.drawcircle(200, 40, 30, paint);
      //绘制正方形
      canvas.drawrect(170, 80, 230, 140, paint);
      //绘制矩形
      canvas.drawrect(170, 150, 230, 190, paint);
      //绘制圆角的矩形
      rectf re31 = new rectf();
      canvas.drawroundrect(re31, 15, 15, paint);
      //绘制椭圆
      rectf re32 =new rectf();
      canvas.drawoval(re32, paint);
      //根据path,绘制三角形
      path path5 = new path();
      path5.moveto(170, 340);
      path5.lineto(230, 340);
      path5.lineto(200, 290);
      path5.close();
      canvas.drawpath(path5, paint);
      //根据path,进行绘制五角形
      path path6 = new path();
      path6.moveto(186, 360);
      path6.lineto(214, 360);
      path6.lineto(230, 392);
      path6.lineto(200, 420);
      path6.lineto(170, 392);
      path6.close();
      canvas.drawpath(path6, paint);
    }
}

2. 使用一个基本的activity来实现自定义的myview组件，

定义一个zidingyiviewtes的activity：

package com.infy.configuration;
import android.app.activity;
import android.os.bundle;
public class zidingyiviewtes extends activity{
    private myview myview =null;
    @override
    protected void oncreate(bundle savedinstancestate) {
      // todo auto-generated method stub
      super.oncreate(savedinstancestate);
      myview = new myview(this, null);
      setcontentview(myview);
    }
}

android的canvas既可以绘制简单的集合图形，也可以直接将一个bitmap绘制到画布上。
最后附上效果图(多了一个椭圆)：

 

希望本文所述对大家android程序设计有所帮助。