air 下载然后缓存文件

gistfile1.as

public static function HasCache(CacheKey:String):Boolean {
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    return f.exists;
    
    f = null;
}
 
public static function PutInCache(CacheKey:String, data:ByteArray):void {
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    var fs:FileStream = new FileStream();
    fs.open(f, FileMode.WRITE);
    fs.writeBytes(data, 0, data.bytesAvailable);
    fs.close();
    
    f = null;
    fs = null;
}
 
public static function PutInCacheUTF(CacheKey:String, data:String):void {
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    var fs:FileStream = new FileStream();
    fs.open(f, FileMode.WRITE);
    fs.writeUTFBytes(data);
    fs.close();
    
    f = null;
    fs = null;
}
 
public static function PutInCacheEncodedImage(CacheKey:String, bitmapData:BitmapData, quality:uint=80):void {
    var data:ByteArray = new JPGEncoder(quality).encode(bitmapData);
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    var fs:FileStream = new FileStream();
    fs.open(f, FileMode.WRITE);
    fs.writeBytes(data, 0, data.bytesAvailable);
    fs.close();
 
    data = null;
    f = null;
    fs = null;
}
 
public static function GetFromCache(CacheKey:String):ByteArray {
    var data:ByteArray = new ByteArray();
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    trace("Getting from cache: " + f.url);
    var fs:FileStream = new FileStream();
    fs.open(f, FileMode.READ);
    fs.readBytes(data, 0, fs.bytesAvailable);
    fs.close();
    
    f = null;
    fs = null;
    
    return data;
}
 
public static function GetFromCacheUTF(CacheKey:String):String {
    var data:String = "";
    var f:File = File.applicationStorageDirectory.resolvePath("cache/" + CacheKey);
    trace("Getting from cache: " + f.url);
    var fs:FileStream = new FileStream();
    fs.open(f, FileMode.READ);
    data = fs.readUTFBytes(fs.bytesAvailable);
    fs.close();
    
    f = null;
    fs = null;
    
    return data;
}