转自http://www.jb51.cc/article/p-okdeplda-sn.html

在xml文件里定义控件的属性，我们已经习惯了android:attrs="",那么我们能不能定义自己的属性能，比如:test:attrs=""呢？答案是肯定的.
好了我就不卖关子了，直接进入主题。大致以下步骤:
一、在res/values文件下定义一个attrs.xml文件.代码如下:

<?xml version="1.0" encoding="utf-8"?>     
    <resources>
        <--注意这里只是声明-->     
        <declare-styleable name="MyView">     
           <attr name="textColor" format="color" />     
           <attr name="textSize" format="dimension" />     
        </declare-styleable>     
    </resources>      

public MyView(Context context,AttributeSet attrs)     
      {     
           super(context,attrs);     
           mPaint = new Paint();     
                 
           TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.MyView);     
           int textColor = a.getColor(R.styleable.MyView_textColor,0XFFFFFFFF);     
           float textSize = a.getDimension(R.styleable.MyView_textSize,36);     
                
           mPaint.setTextSize(textSize);     
           mPaint.setColor(textColor);     
                
           a.recycle();     
       }      

MyView.java全部代码如下:

ackage com.teleca;     
    import android.content.Context;     
    import android.content.res.TypedArray;     
    import android.graphics.Canvas;     
    import android.graphics.Color;     
    import android.graphics.Paint;     
    import android.graphics.Rect;     
    import android.graphics.Paint.Style;     
    import android.util.AttributeSet;     
    import android.view.View;     
    public class MyView extends View {     
    private Paint mPaint;     
    private Context mContext;     
    private static final String mString = "Welcome to Mr Wei's blog";     
       public MyView(Context context) {     【用来在代码中创建控件】
           super(context);     
           mPaint = new Paint();     
       }     
       public MyView(Context context,AttributeSet attrs)//【如果是在布局文件中定义的控件，就会调用该构造函数】
       {     
           super(context,attrs);     
           mPaint = new Paint();     
                
           TypedArray a = context.obtainStyledAttributes(attrs,36);     
                
           mPaint.setTextSize(textSize);     
           mPaint.setColor(textColor);     
                
           a.recycle();     
       }     
       @Override    
       protected void onDraw(Canvas canvas) {     
           // TODO Auto-generated method stub     
           super.onDraw(canvas);     
           //设置填充     
           mPaint.setStyle(Style.FILL);     
                
           //画一个矩形,前俩个是矩形左上角坐标，后面俩个是右下角坐标     
           canvas.drawRect(new Rect(10,10,100,100),mPaint);     
                
           mPaint.setColor(Color.BLUE);     
           //绘制文字     
           canvas.drawText(mString,110,mPaint);     
       }     
   }    

<?xml   
    version="1.0" encoding="utf-8"?>  
    <LinearLayout   
    xmlns:android="http://schemas.android.com/apk/res/android" 
    <--这里相当于声明命名空间吧-->                
    xmlns:test="http://schemas.android.com/apk/res/com.teleca" 
        android:orientation="vertical" 
        android:layout_width="fill_parent" 
        android:layout_height="fill_parent" 
        >  
    <TextView    
        android:layout_width="fill_parent"   
        android:layout_height="wrap_content"   
        android:text="@string/hello" 
        />  
<--注意要加包名哦！-->
    <com.teleca.MyView  
        android:layout_width="fill_parent"   
        android:layout_height="fill_parent"   
        test:textSize="20px" 
        test:textColor="#fff" 
    />  

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.teleca"
      android:versionCode="1"
      android:versionName="1.0">