android-自定义view创建概述

 1 public class myview extends View{
 2 
 3     public myview(Context context, AttributeSet attrs) {  //构造器
 4         super(context, attrs);
 5         // TODO Auto-generated constructor stub
 6     }
 7     
 8     protected void onDraw(Canvas canvas)
 9     {
10         super.onDraw(canvas);            
11         canvas.drawColor(Color.BLACK);            //绘制黑色背景
12         Paint paint=new Paint();                  //创建画笔
13         paint.setColor(Color.RED);
14         canvas.drawRect(10,10,110,110, paint);    //画矩形
15         canvas.drawText("这是字符串", 10, 130, paint);//写字
16         RectF rf1=new RectF(10,130,110,230);     //定义一个矩形
17         canvas.drawArc(rf1, 0, 45, true, paint);//画弧，顺时针
18         canvas.drawLine(150, 10, 250, 110, paint);//画线
19         RectF rf2=new RectF(150,130,250,230);
20         canvas.drawOval(rf2, paint);          //画圆
21         
22     }
23 
24 }

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
    <com.example.myview.myview
        android:id="@+id/myview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        />

</RelativeLayout>

 1 package com.example.myview;
 2 
 3 import android.content.Context;
 4 import android.graphics.Bitmap;
 5 import android.graphics.BitmapFactory;
 6 import android.graphics.Canvas;
 7 import android.graphics.Color;
 8 import android.graphics.Paint;
 9 import android.util.AttributeSet;
10 import android.view.View;
11 
12 public class myview_picture extends View{
13     Bitmap mb;
14     Paint paint;
15 
16     public myview_picture(Context context, AttributeSet attrs) {
17         super(context, attrs);
18         // TODO Auto-generated constructor stub
19         this.initBitmap();              //初始化图片
20     }
21     
22     public void initBitmap()
23     {
24         paint=new Paint();
25         mb=BitmapFactory.decodeResource(getResources(), R.drawable.indexgundom);
26     }
27     @Override
28     protected void onDraw(Canvas canvas)
29     {
30         super.onDraw(canvas);
31         paint.setAntiAlias(true);               //打开抗锯齿
32         paint.setColor(Color.WHITE);            //设置画笔颜色
33         paint.setTextSize(15);                 //我猜是设置字体大小
34         canvas.drawBitmap(mb, 10,10, paint);     //画图
35         canvas.drawText("图片的宽度："+mb.getWidth(), 20, 220, paint); //写字
36         canvas.drawText("图片的高度"+mb.getHeight(), 150, 220, paint);
37     }
38     
39 
40 }