详解Android自定义控件属性TypedArray以及attrs

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
 
 <attr name="titleText" format="string" /> 
 <attr name="titleTextColor" format="color" /> 
 <attr name="titleTextSize" format="dimension" /> 
 
 <declare-styleable name="AuthCodeView"> 
 <attr name="titleText" /> 
 <attr name="titleTextColor" /> 
 <attr name="titleTextSize" /> 
 </declare-styleable> 
 
</resources> 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:tools="http://schemas.android.com/tools" 
 xmlns:authcodeview="http://schemas.android.com/apk/res/com.example.authcodeview" 
 android:id="@+id/LinearLayout1" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:orientation="vertical" > 
 
 <LinearLayout 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content" > 
 
 <com.example.authcodeview.view.AuthCodeView 
  android:id="@+id/AuthCodeView" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:padding="10dp" 
  authcodeview:titleText="3712" 
  authcodeview:titleTextColor="#00ffff" 
  authcodeview:titleTextSize="40sp" /> 
 
 <TextView 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:text="点击验证码，换一张" /> 
 </LinearLayout> 
 
 <LinearLayout 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content" > 
 
 <TextView 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:text="输入验证码" /> 
 
 <EditText 
  android:id="@+id/editText1" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:ems="10" 
  android:inputType="number" > 
 
  <requestFocus /> 
 </EditText> 
 </LinearLayout> 
 
 <Button 
 android:id="@+id/button1" 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content" 
 android:text="验证" /> 
 
</LinearLayout> 

/** 
 * 获得我自定义的样式属性 
 * 
 * @param context 
 * @param attrs 
 * @param defStyle 
 */ 
public AuthCodeView(Context context, AttributeSet attrs, int defStyle) 
{ 
 super(context, attrs, defStyle); 
 /** 
 * 获得我们所定义的自定义样式属性 
 */ 
 TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.AuthCodeView, defStyle, 0); 
 
 //获取在attr文件下，名字为AuthCodeView的declare-styleable属性有几个 
 int n = a.getIndexCount(); 
 for (int i = 0; i < n; i++) 
 { 
 int attr = a.getIndex(i); 
 switch (attr) 
 { 
 //这个属性可以不要，因为都是随机产生 
 case R.styleable.AuthCodeView_titleText: 
  mTitleText = a.getString(attr); 
  break; 
 case R.styleable.AuthCodeView_titleTextColor: 
  // 默认颜色设置为黑色 
  mTitleTextColor = a.getColor(attr, Color.BLACK); 
  break; 
 case R.styleable.AuthCodeView_titleTextSize: 
  // 默认设置为16sp，TypeValue也可以把sp转化为px 
  mTitleTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension( 
   TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics())); 
  break; 
 
 } 
 
 } 
 a.recycle(); 
 }