Android使用继承View类来绘图

添加新类MyView继承View

在MyView中实例化Paint

 1 package com.hu.viewdemo; 2  3 import android.content.Context; 4 import android.graphics.Canvas; 5 import android.graphics.Color; 6 import android.graphics.Paint; 7 import android.graphics.Paint.Style; 8 import android.graphics.Path; 9 import android.view.View;10 11 public class MyView extends View{12 13     private Paint paint;//画笔14     15     public MyView(Context context) {16         super(context);17         // TODO Auto-generated constructor stub18         paint = new Paint();19         paint.setColor(Color.RED);//设置画笔颜色20         paint.setAntiAlias(true);//设置抗锯齿21         paint.setStyle(Style.STROKE);//设置为空心22         paint.setStrokeWidth(1);//设置空心边距为123         paint.setTextSize(40);//设置字符串高24     }25 26     @Override27     protected void onDraw(Canvas canvas) {28         // TODO Auto-generated method stub29         super.onDraw(canvas);30         canvas.drawCircle(100, 100, 20, paint);//画个圆31         canvas.drawText("这是字符串", 0, 40, paint);//写字,指定左下角位置32         canvas.drawRect(100, 200, 200, 300, paint);//画矩形33         Path path=new Path();//创建路径34         path.moveTo(300, 200);35         path.lineTo(300, 300);36         path.lineTo(200, 400);//指定路径37         canvas.drawPath(path, paint);//沿路径绘图38     }39 40 }

然后在activity类中将MyView的实例设为ContentView

 1 package com.hu.viewdemo; 2  3 import android.app.Activity; 4 import android.os.Bundle; 5  6 public class ViewDemoActivity extends Activity { 7     /** Called when the activity is first created. */ 8     @Override 9     public void onCreate(Bundle savedInstanceState) {10         super.onCreate(savedInstanceState);11         MyView mv=new MyView(this);12         setContentView(mv);13     }14 }