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sprite:
java -Xdebug -Xrunjdwp:transpor ...
izpack 调试 -
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这里有一套非常不错的 SparkSkin 主题皮肤,更新很频 ...
Flex Skin (Spark) -
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在windows 7下,需要用admin权限去运行cmd窗口, ...
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其实对于非常简单的背景色设置已经够用了……
Flex4 背景设置 -
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还有一个非主流的方式,直接设置opaqueBackground ...
Flex4 背景设置
1. Dictionary 与 Object的区别在帮助文档中说的很清楚了:
Dictionary 类用于创建属性的动态集合,该集合使用全等运算符 (===
)
进行键比较。将对象用作键时,会使用对象的标识来查找对象,而不是使用在对象上调用 toString()
所返回的值。Dictionary
集合中的原始(内置)对象(例如 Number)的行为方式与它们作为常规对象的属性时的行为方式相同。
并给出了例子:
var dict:Dictionary = new Dictionary(); var obj:Object = new Object(); var key:Object = new Object(); key.toString = function() { return "key" } dict[key] = "Letters"; obj["key"] = "Letters"; dict[key] == "Letters"; // true obj["key"] == "Letters"; // true obj[key] == "Letters"; // true because key == "key" is true because key.toString == "key" dict["key"] == "Letters"; // false because "key" === key is false delete dict[key]; //removes the key
2. 在这里,你还要理解 == 和 === 有何区别
在帮助文档中也做了很好的说明:
测试两个表达式是否相等,但不执行自动数据转换。如果两个表达式(包括它们的数据类型)相等,则结果为 true
。
全等运算符 (===
) 与等于运算符 (==
) 在以下三个方面相同:
- 数字和布尔值按值进行比较,如果它们具有相同的值,则视为相等。
- 如果字符串表达式具有相同的字符数,而且这些字符都相同,则这些字符串表达式相等。
- 表示对象、数组和函数的变量按引用进行比较。如果两个这样的变量引用同一个对象、数组或函数,则它们相等。而两个单独的数组即使具有相同数量的元素,也永远不会被视为相等。
全等运算符 (===
) 与等于运算符 (==
) 仅在下列两个方面不同:
- 全等运算符仅针对数字类型(Number、int 和 uint)执行自动数据转换,而等于运算符 () 针对所有的原始数据类型执行自动数据转换。
- 当比较
null
和undefined
时,全等运算符将返回false
。
并给出了例子:
//下例说明当值和数据类型都匹配时,全等运算符 (===) 与等于运算符 (==) 相同: var string1:String = "5"; var string2:String = "5"; trace(string1 == string2); // true trace(string1 === string2); // true //下例说明全等运算符不将 String 类型的数据转换为 Number 类型的数据,但是等于运算符 (==) 却进行这样的转换: // The equality (==) operator converts 5 to "5", but the strict equality operator does not var string1:String = "5"; var num:Number = 5; trace(string1 == num); // true trace(string1 === num); // false //下例说明全等运算符不将布尔值转换为数字,但是等于运算符却进行这样的转换: var num:Number = 1; var bool:Boolean = true; trace(num == bool); // true trace(num === bool); // false下例说明全等运算符确实转换 int 和 uint 数据类型: var num1:Number = 1; var num2:int = 1; var num3:uint = 1; trace(num1 === num2); // true trace(num1 === num3); // true下例说明全等运算符将 null 和 undefined 视为不相等,但是等于运算符却将它们视为相等: trace(null == undefined); // true trace(null === undefined); // false
3. 还要注意的是 hasOwnProperty() 方法
指示对象是否已经定义了指定的属性。如果目标对象具有与
name
参数指定的字符串匹配的属性,则此方法返回
true
;否则返回 false
。(在这里,你出入进去的是string 类型的值,即使你传入的是一个对象,它也会调用对象的toString()方法转化为string 然后进行比较.)
所以,如果你的dictionary的key值是对象,你怎么查找是否拥有此key值呢?
public function containsKey(key:*):Boolean { for(var k:* in dict) { if(k === key) { return true; } } return dict.hasOwnProperty(key); }
4.As3 中没有Map 类,不过可以自己模拟一个。
package { import flash.utils.Dictionary; public class DictCache implements ICache { /** * * Defines the underlying object which contains the key / value * mappings of an <code>ICache</code> implementation. * * @see http://livedocs.adobe.com/flex/3/langref/flash/utils/Dictionary.html * */ protected var dict:Dictionary; /** * * Creates a new DictCache instance. By default, weak key * references are used in order to ensure that objects are * eligible for Garbage Collection immediatly after they * are no longer being referenced, if the only reference to * an object is in the specified Dictionary object, the key is * eligible for garbage collection and is removed from the * table when the object is collected * * * @example * * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache( false ); * * </listing> * * @param specifies if weak key references should be used * */ public function DictCache(weakReferences:Boolean=true) { dict = new Dictionary(weakReferences); } /** * * Adds a key and value to the DictCache instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "user", userVO ); * * </listing> * * @param the key to add to the cache * @param the value of the specified key * */ public function put(key:*, value:*):void { dict[key] = value; } /** * * Places all name / value pairs into the current * <code>IMap</code> instance. * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var table:Object = {a: "foo", b: "bar"}; * var cache:ICache = new DictCache(); * cache.putAll( table ); * * trace( cache.getValues() ); * // foo, bar * * </listing> * * @param an <code>Object</code> of name / value pairs * */ public function putAll(table:Dictionary):void { for (var prop:String in table) { put(prop, table[prop]); } } /** * * Removes a key and value from the DictCache instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.remove( "admin" ); * * </listing> * * @param the key to remove from the cache * */ public function remove(key:*):void { delete dict[key]; } /** * * Determines if a key exists in the DictCache instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * * trace( cache.containsKey( "admin" ) ); //true * * </listing> * * @param the key in which to determine existance in the cache * @return true if the key exisits, false if not * */ public function containsKey(key:*):Boolean { for(var k:* in dict) { if(k === key) { return true; } } return dict.hasOwnProperty(key); } /** * * Determines if a value exists in the DictCache instance * * <p> * If multiple keys exists in the map with the same value, * the first key located which is mapped to the specified * key will be returned. * </p> * * @example * * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * * trace( cache.containsValue( adminVO ) ); //true * * </listing> * * @param the value in which to determine existance in the cache * @return true if the value exisits, false if not * */ public function containsValue(value:*):Boolean { var result:Boolean=false; for (var key:* in dict) { if (dict[key] == value) { result=true; break; } } return result; } /** * * Returns the value of the specified key from the DictCache * instance. * * <p> * If multiple keys exists in the map with the same value, * the first key located which is mapped to the specified * value will be returned. * </p> * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * * trace( cache.getKey( adminVO ) ); //admin * * </listing> * * @param the key in which to retrieve the value of * @return the value of the specified key * */ public function getKey(value:*):* { var id:String=null; for (var key:*in dict) { if (dict[key] == value) { id=key; break; } } return id; } /** * * Returns each key added to the HashMap instance * * @example * * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * * trace( cache.getKeys() ); //admin, editor * * </listing> * * @return Array of key identifiers * */ public function getKeys():Array { var keys:Array=[]; for (var key:* in dict) { keys.push(key); } return keys; } /** * * Retrieves the value of the specified key from the DictCache instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * * trace( cache.getValue( "editor" ) ); //[object, editorVO] * * </listing> * * @param the key in which to retrieve the value of * @return the value of the specified key, otherwise returns undefined * */ public function getValue(key:*):* { return dict[key]; } /** * * Retrieves each value assigned to each key in the DictCache instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * * trace( cache.getValues() ); //[object, adminVO],[object, editorVO] * * </listing> * * @return Array of values assigned for all keys in the cache * */ public function getValues():Array { var values:Array=[]; for (var key:* in dict) { values.push(dict[key]); } return values; } /** * * Determines the size of the HashMap instance * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * * trace( cache.size() ); //2 * * </listing> * * @return the current size of the cache instance * */ public function size():int { var length:int=0; for (var key:*in dict) { length++; } return length; } /** * * Determines if the current DictCache instance is empty * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var map:IMap = new HashMap(); * trace( map.isEmpty() ); //true * * map.put( "admin", adminVO ); * trace( map.isEmpty() ); //false * * </listing> * * @return true if the current map is empty, false if not * */ public function isEmpty():Boolean { return size() <= 0; } /** * * Resets all key value assignments in the DictCache instance to null * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * cache.reset(); * * trace( cache.getValues() ); //null, null * * </listing> * */ public function reset():void { for (var key:* in dict) { dict[key]=undefined; } } /** * * Resets all key / values defined in the DictCache instance to null * with the exception of the specified key * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * * trace( cache.getValues() ); //[object, adminVO],[object, editorVO] * * cache.resetAllExcept( "editor", editorVO ); * trace( cache.getValues() ); //null,[object, editorVO] * * </listing> * * @param the key which is not to be cleared from the cache * */ public function resetAllExcept(keyId:*):void { for (var key:* in dict) { if (key != keyId) { dict[key]=undefined; } } } /** * * Resets all key / values in the DictCache instance to null * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * trace( cache.size() ); //2 * * cache.clear(); * trace( cache.size() ); //0 * * </listing> * */ public function clear():void { for (var key:* in dict) { remove(key); } } /** * * Clears all key / values defined in the DictCache instance * with the exception of the specified key * * @example * <listing version="3.0"> * * import com.lombardrisk.utils.DictCache; * import com.lombardrisk.utils.ICache; * * var cache:ICache = new DictCache(); * cache.put( "admin", adminVO ); * cache.put( "editor", editorVO ); * trace( cache.size() ); //2 * * cache.clearAllExcept( "editor", editorVO ); * trace( cache.getValues() ); //[object, editorVO] * trace( cache.size() ); //1 * * </listing> * * @param the key which is not to be cleared from the cache * */ public function clearAllExcept(keyId:*):void { for (var key:* in dict) { if (key != keyId) { remove(key); } } } } }
ICache 类:
package { import flash.utils.Dictionary; /** * * Defines the contract for lightweight Cache implementations * which are to expose an API into a managed collection of key * value pairs * */ public interface ICache { /** * * Adds a key / value pair to the current cache * * @param the key to add to the cache * @param the value of the specified key * */ function put(key:*, value:*) : void; /** * * Places all name / value pairs into the current * <code>ICache</code> instance. * * @param an <code>Object</code> of name / value pairs * */ function putAll(table:Dictionary) : void; /** * * Removes a key / value from the ICache instance * * @param key to remove from the cache * */ function remove(key:*) : void; /** * * Determines if a key exists in the HashMap instance * * @param the key in which to determine existance in the map * @return true if the key exisits, false if not * */ function containsKey(key:*) : Boolean; /** * * Determines if a value exists in the ICache instance * * @param the value in which to determine existance in the cache * @return true if the value exisits, false if not * */ function containsValue(value:*) : Boolean; /** * * Returns a key value from the ICache instance * * @param the key in which to retrieve the value of * @return the value of the specified key * */ function getKey(value:*) : *; /** * * Returns a key value from the ICache instance * * @param the key in which to retrieve the value of * @return the value of the specified key * */ function getValue(key:*) : *; /** * * Returns each key added to the ICache instance * * @return String Array of key identifiers * */ function getKeys() : Array; /** * * Returns each value assigned to each key in the ICache instance * * @return Array of values assigned for all keys in the cache * */ function getValues() : Array; /** * * Retrieves the size of the ICache instance * * @return the current size of the cache instance * */ function size() : int; /** * * Determines if the HashMap instance is empty * * @return true if the current map is empty, false if not * */ function isEmpty() : Boolean; /** * * Resets all key value assignments in the ICache instance to null * */ function reset() : void; /** * * Resets all key / values defined in the ICache instance to null * */ function resetAllExcept(key:*) : void; /** * * Clears all key / values defined in the ICache instance * */ function clear() : void; /** * * Clears all key / values defined in the ICache instance * with the exception of the specified key * */ function clearAllExcept(key:*) : void; } }
发表评论
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AS3 int uint Number
2013-07-19 16:55 38481) int 类可使用表示为 32 位带符号整数的数据类型。 ... -
AS3 显示对象类继承关系&类结构图
2012-12-24 14:58 1439AS3 的显示对象类的继承关系可以归纳为一个统一,两个层次. ... -
stopImmediatePropagation&stopPropagation 区别
2012-12-19 17:51 5025stopImmediatePropagation 与 stop ... -
AS3 抽象类
2012-11-22 17:21 1731AS3 是没有抽象类的,如果非要用抽象类的话,可以模拟出抽象类 ...
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