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。