android 画图小例子

package com.xw.android; import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.RectF; import android.graphics.Paint.Style; import android.os.Bundle; import android.view.View; public class Draw extends Activity { /**画简单的图形：点、直线、三角形、四边形、圆、弧 * */ //编写一类继承View，并重写其onDraw方法 class MyView extends View{ //定义了6个Paint属性实例 private Paint paint1=new Paint(); private Paint paint2=new Paint(); private Paint paint3=new Paint(); private Paint paint4=new Paint(); private Paint paint5=new Paint(); private Paint paint6=new Paint(); public MyView(Context context) { super(context); setBackgroundColor(Color.WHITE); // 在构造函数中，设置Paint属性实例:颜色,大小 paint1.setColor(Color.BLUE); paint1.setStrokeWidth(8); paint2.setColor(Color.RED); paint2.setStrokeWidth(2); paint3.setColor(Color.GREEN); paint3.setStrokeWidth(5); paint4.setColor(Color.YELLOW); paint4.setStrokeWidth(2); paint5.setColor(Color.BLUE); paint5.setStrokeWidth(4); paint6.setColor(Color.DKGRAY); paint6.setStrokeWidth(2); } @Override protected void onDraw(Canvas canvas) { //画点 canvas.drawPoint(10, 10, paint1); canvas.drawPoints(new float[] { 20, 20, 20, 35, 20, 50 }, paint1); //画直线 canvas.drawLine(20, 60, 300, 60, paint2); //画多条直线：三角形 canvas.drawLines(new float[] { 70, 70, 70, 170, 70, 170,170,170,170,170,70,70}, paint2); //画四条直线：四过形 canvas.drawLines(new float[] { 70, 200, 70, 300, 70, 300,170,300,170,300,170,200,170,200,70,200}, paint3); //画圆 canvas.drawCircle(230, 150, 45, paint4); //默认是实心圆，要画空心的需设置Style为STROKE paint5.setStyle(Style.STROKE); canvas.drawCircle(230, 150, 50, paint5); //画弧 RectF rectF = new RectF();//外切矩形左上角，右下角坐标，共四个值 rectF.left = 30; rectF.top = 250; rectF.right = 120; rectF.bottom = 380; boolean useCenter=true;//是设是否过圆心连线 canvas.drawArc(rectF, 0, 200, useCenter, paint6); RectF rectF2 = new RectF();//外切矩形左上角，右下角坐标，共四个值 rectF2.left = 20; rectF2.top = 260; rectF2.right = 130; rectF2.bottom = 390; boolean useCenter2=false;//是设是否过圆心连线 paint6.setStyle(Style.STROKE); canvas.drawArc(rectF2, 0, 200, useCenter2, paint6); } } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new MyView(this)); } }