这篇文章主要介绍了android编程开发之在canvas中利用path绘制基本图形的方法,涉及android基本的图形绘制技巧,结合实例分析了绘制圆形,矩形,椭圆,三角形等基本图形的实现方法,需要的朋友可以参考下
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)：
