Android中自定义属性的使用

private void init(Context context, AttributeSet attributeSet) {  
       if (attributeSet != null) {  
           TypedArray a = context.obtainStyledAttributes(attributeSet, R.styleable.RoundAngleImageView);  
           assert a != null;  
           roundWidth = a.getDimensionPixelSize(R.styleable.RoundAngleImageView_roundWidth, roundWidth);  
           roundHeight = a.getDimensionPixelSize(R.styleable.RoundAngleImageView_roundHeight, roundHeight);  
       } else {  
           float density = context.getResources().getDisplayMetrics().density;  
           roundWidth = (int) (roundWidth * density);  
           roundHeight = (int) (roundHeight * density);  
       }  
  
       paint = new Paint();  
       paint.setColor(Color.WHITE);  
       paint.setAntiAlias(true);  
       paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));  
  
       paint2 = new Paint();  
       paint2.setXfermode(null);  
      a.recycle();//为了保持以后使用的一致性，需要回收  

注意最后调用TypedArray的recycle方法。

以上三步，搞定。

attrs.xml format属性说明：

    "reference" //引用
    "color" //颜色
    "boolean" //布尔值
    "dimension" //尺寸值
    "float" //浮点值
    "integer" //整型值
    "string" //字符串
    "fraction" //百分数,比如200%

枚举型的格式：
<attr name="orientation">
  <enum name="horizontal" value="0" />
  <enum name="vertical" value="1" />
</attr>

XML文件中使用：  
android:orientation = "vertical"

标志位、位或运算，格式如下：
<attr name="windowSoftInputMode">
  <flag name = "stateUnspecified" value = "0" />
  <flag name = "stateUnchanged" value = "1" />
  <flag name = "stateHidden" value = "2" />
  <flag name = "stateAlwaysHidden" value = "3" />
  <flag name = "stateVisible" value = "4" />
  <flag name = "stateAlwaysVisible" value = "5" />
  <flag name = "adjustUnspecified" value = "0x00" />
  <flag name = "adjustResize" value = "0x10" />
  <flag name = "adjustPan" value = "0x20" />
  <flag name = "adjustNothing" value = "0x30" />
</attr>

XML文件中使用：
android:windowSoftInputMode = "stateUnspecified | stateUnchanged | stateHidden"> &nbsp;

属性定义可以指定多种类型：
<attr name = "background" format = "reference|color" /> &nbsp;

XML文件中使用：
android:background = "@drawable/图片ID|#00FF00"

1. reference：参考某一资源ID。
    （1）属性定义：
           <declare-styleable name = "名称">
                  <attr name = "background" format = "reference" />
           </declare-styleable>
    （2）属性使用：
            <ImageView
                    android:layout_width = "42dip"
                    android:layout_height = "42dip"
                    android:background = "@drawable/图片ID"
                    />
2. color：颜色值。
    （1）属性定义：
           <declare-styleable name = "名称">
                  <attr name = "textColor" format = "color" />
           </declare-styleable>
    （2）属性使用：
            <TextView
                    android:layout_width = "42dip"
                    android:layout_height = "42dip"
                    android:textColor = "#00FF00"
                    />
3. boolean：布尔值。
    （1）属性定义：
           <declare-styleable name = "名称">
                  <attr name = "focusable" format = "boolean" />
           </declare-styleable>
    （2）属性使用：
            <Button
                   android:layout_width = "42dip"
                   android:layout_height = "42dip"
                   android:focusable = "true"
                   />
4. dimension：尺寸值。
    （1）属性定义：
           <declare-styleable name = "名称">
                  <attr name = "layout_width" format = "dimension" />
           </declare-styleable>
    （2）属性使用：
            <Button
                   android:layout_width = "42dip"
                   android:layout_height = "42dip"
                   />
5. float：浮点值。
    （1）属性定义：
           <declare-styleable name = "AlphaAnimation">
                  <attr name = "fromAlpha" format = "float" />
                  <attr name = "toAlpha" format = "float" />
           </declare-styleable>
    （2）属性使用：
            <alpha
                  android:fromAlpha = "1.0"
                  android:toAlpha = "0.7"
                  />
6. integer：整型值。
    （1）属性定义：
           <declare-styleable name = "AnimatedRotateDrawable">
                  <attr name = "visible" />
                  <attr name = "frameDuration" format="integer" />
                  <attr name = "framesCount" format="integer" />
                  <attr name = "pivotX" />
                  <attr name = "pivotY" />
                  <attr name = "drawable" />
           </declare-styleable>
    （2）属性使用：
           <animated-rotate
                  xmlns:android = "http://schemas.android.com/apk/res/android" 
                  android:drawable = "@drawable/图片ID" 
                  android:pivotX = "50%" 
                  android:pivotY = "50%" 
                  android:framesCount = "12" 
                  android:frameDuration = "100"
                  />
7. string：字符串。
    （1）属性定义：
           <declare-styleable name = "MapView">
                  <attr name = "apiKey" format = "string" />
           </declare-styleable>
    （2）属性使用：
           <com.google.android.maps.MapView
                   android:layout_width = "fill_parent"
                   android:layout_height = "fill_parent"
                   android:apiKey = "0jOkQ80oD1JL9C6HAja99uGXCRiS2CGjKO_bc_g"
                   />
8. fraction：百分数。
    （1）属性定义：
           <declare-styleable name="RotateDrawable">
                  <attr name = "visible" />
                  <attr name = "fromDegrees" format = "float" />
                  <attr name = "toDegrees" format = "float" />
                  <attr name = "pivotX" format = "fraction" />
                  <attr name = "pivotY" format = "fraction" />
                  <attr name = "drawable" />
           </declare-styleable>
    （2）属性使用：
           <rotate  xmlns:android = "http://schemas.android.com/apk/res/android"
　　            android:interpolator = "@anim/动画ID"
                android:fromDegrees = "0"
　　            android:toDegrees = "360"
                android:pivotX = "200%"
                android:pivotY = "300%"
　　            android:duration = "5000"
                android:repeatMode = "restart"
                android:repeatCount = "infinite"
                  />
9. enum：枚举值。
    （1）属性定义：
           <declare-styleable name="名称">
                  <attr name="orientation">
                         <enum name="horizontal" value="0" />
                         <enum name="vertical" value="1" />
                  </attr>           
           </declare-styleable>
    （2）属性使用：
           <LinearLayout
                   xmlns:android = "http://schemas.android.com/apk/res/android"
                   android:orientation = "vertical"
                   android:layout_width = "fill_parent"
                   android:layout_height = "fill_parent"
                   >
           </LinearLayout>
10. flag：位或运算。
     （1）属性定义：
            <declare-styleable name="名称">
                   <attr name="windowSoftInputMode">
                           <flag name = "stateUnspecified" value = "0" />
                           <flag name = "stateUnchanged" value = "1" />
                           <flag name = "stateHidden" value = "2" />
                           <flag name = "stateAlwaysHidden" value = "3" />
                           <flag name = "stateVisible" value = "4" />
                           <flag name = "stateAlwaysVisible" value = "5" />
                           <flag name = "adjustUnspecified" value = "0x00" />
                           <flag name = "adjustResize" value = "0x10" />
                           <flag name = "adjustPan" value = "0x20" />
                           <flag name = "adjustNothing" value = "0x30" />
                    </attr>        
            </declare-styleable>
     （2）属性使用：
            <activity
                  android:name = ".StyleAndThemeActivity"
                  android:label = "@string/app_name"
                  android:windowSoftInputMode = "stateUnspecified | stateUnchanged　|　stateHidden">
                  <intent-filter>
                         <action android:name = "android.intent.action.MAIN" />
                         <category android:name = "android.intent.category.LAUNCHER" />
                  </intent-filter>
            </activity>
     注意：
     属性定义时可以指定多种类型值。
    （1）属性定义：
           <declare-styleable name = "名称">
                  <attr name = "background" format = "reference|color"/>
           </declare-styleable>
    （2）属性使用：
            <ImageView
                    android:layout_width = "42dip"
                    android:layout_height = "42dip"
                    android:background = "@drawable/图片ID|#00FF00"
                    />