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。

先来看看源码：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>

最终的效果

项目结构图：