iOS開發swift版非同步載入網狀圖片(帶緩衝和預設圖片)

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iOS開發之swift版非同步載入網狀圖片

    與SDWebImage非同步載入網狀圖片的功能相似，只是代碼比較簡單，功能沒有SD的完善與強大，支援預設添加圖片，支援本機快取。

     非同步載入圖片的核心代碼如下：

 func setZYHWebImage(url:NSString?, defaultImage:NSString?, isCache:Bool){        var ZYHImage:UIImage?        if url == nil {            return        }        //設定預設圖片        if defaultImage != nil {            self.image=UIImage(named: defaultImage!)        }        //是否進行緩衝處理        if isCache {        //緩衝管理類            var data:NSData?=ZYHWebImageChcheCenter.readCacheFromUrl(url!)            if data != nil {                ZYHImage=UIImage(data: data!)                self.image=ZYHImage            }else{            //擷取非同步線程               var dispath=dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)                dispatch_async(dispath, { () -> Void in                    var URL:NSURL = NSURL(string: url!)!                    var data:NSData?=NSData(contentsOfURL: URL)                    if data != nil {                        ZYHImage=UIImage(data: data!)                        //寫緩衝                        ZYHWebImageChcheCenter.writeCacheToUrl(url!, data: data!)                        //主線程中重新整理UI                        dispatch_async(dispatch_get_main_queue(), { () -> Void in                            //重新整理主UI                            self.image=ZYHImage                        })                    }                                    })            }        }else{            var dispath=dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)            dispatch_async(dispath, { () -> Void in                var URL:NSURL = NSURL(string: url!)!                var data:NSData?=NSData(contentsOfURL: URL)                if data != nil {                    ZYHImage=UIImage(data: data!)                    //寫緩衝                    dispatch_async(dispatch_get_main_queue(), { () -> Void in                        //重新整理主UI                        self.image=ZYHImage                    })                }                            })        }    }    }

緩衝的處理這裡採用的是寫檔案的方式，通過檔案名稱來對緩衝進行管理，這個架構還不完善，後面會加入緩衝清除等功能。緩衝的核心代碼如下：

class func readCacheFromUrl(url:NSString)->NSData?{        var data:NSData?        var path:NSString=ZYHWebImageChcheCenter.getFullCachePathFromUrl(url)        if NSFileManager.defaultManager().fileExistsAtPath(path) {            data=NSData.dataWithContentsOfMappedFile(path) as? NSData        }        return data    }        class func writeCacheToUrl(url:NSString, data:NSData){        var path:NSString=ZYHWebImageChcheCenter.getFullCachePathFromUrl(url)       println(data.writeToFile(path, atomically: true))    }    //設定緩衝路徑    class func getFullCachePathFromUrl(url:NSString)->NSString{        var chchePath=NSHomeDirectory().stringByAppendingString("/Library/Caches/MyCache")        var fileManager:NSFileManager=NSFileManager.defaultManager()        fileManager.fileExistsAtPath(chchePath)        if !(fileManager.fileExistsAtPath(chchePath)) {            fileManager.createDirectoryAtPath(chchePath, withIntermediateDirectories: true, attributes: nil, error: nil)        }        //進行字串處理        var newURL:NSString        newURL=ZYHWebImageChcheCenter.stringToZYHString(url)        chchePath=chchePath.stringByAppendingFormat("/%@", newURL)        return chchePath    }        class func stringToZYHString(str:NSString)->NSString{        var newStr:NSMutableString=NSMutableString()        for var i:NSInteger=0; i < str.length; i++ {            var c:unichar=str.characterAtIndex(i)            if (c>=48&&c<=57)||(c>=65&&c<=90)||(c>=97&&c<=122){                newStr.appendFormat("%c", c)            }        }        return newStr.copy() as NSString            }

架構的github地址，歡迎指正與擴充：https://github.com/ZYHshao/swift-ZYHWebImage

因xcode的版本不同，swift語言文法隨環境時常會變化，此版本在6.1中可用，更高版本中需要修改少部分即可。

iOS開發swift版非同步載入網狀圖片(帶緩衝和預設圖片)