Android中自定义属性（attrs.xml，TypedArray）的使用

该实例是在自定义View上使用自定义属性的。

MyView.java 

package com.adnroid.test;  

import com.adnroid.test.R;  

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 myPaint;  
    private static final String myString = "Welcome to our Zoon!";  

    public MyView(Context context) {  
        super(context);  
        // TODO Auto-generated constructor stub  
     }  

    public MyView(Context context, AttributeSet attr) {  
        super(context, attr);  
         myPaint = new Paint();  
         TypedArray a = context.obtainStyledAttributes(attr, R.styleable.myView);//TypedArray是一个数组容器  
        float textSize = a.getDimension(R.styleable.myView_textSize, 30);//防止在XML文件里没有定义，就加上了默认值30  
        int textColor = a.getColor(R.styleable.myView_textColor, 0xFFFFFFFF);//同上,这里的属性是:名字_属性名  
         myPaint.setTextSize(textSize);  
         myPaint.setColor(textColor);  
         a.recycle();//我的理解是：返回以前取回的属性，供以后使用。以前取回的可能就是textSize和textColor初始化的那段  
     }  
    @Override 
    protected void onDraw(Canvas canvas) {  
        // TODO Auto-generated method stub  
        super.onDraw(canvas);  
        //myPaint = new Paint();  
         myPaint.setColor(Color.RED);  
         myPaint.setStyle(Style.FILL);  

         canvas.drawRect(new Rect(10,10,100,100), myPaint);  
         myPaint.setColor(Color.WHITE);  
         canvas.drawText(myString, 10, 100, myPaint);  
     }  

}  

attrs.xml

<?xml version="1.0" encoding="utf-8"?>  
<resources>  
    <declare-styleable name="myView">  
        <attr name="textColor" format="color"/>  
        <attr name="textSize" format="dimension"/>  
    </declare-styleable>  
</resources>

main.xml 

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:test="http://schemas.android.com/apk/res/com.adnroid.test" 
    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" 
    />  
<com.adnroid.test.MyView 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    test:textSize="10px" 
    test:textColor="#fff" 
    />  
</LinearLayout>