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相关推荐：ios 多线程之GCD
一、简介 在iOS所有实现多线程的方案中，GCD应该是最有魅力的，因为GCD本身是苹果公司为多核的并行运算提出的解决方案。GCD在工作时会自动利用更多的处理器核心，以充分利用更强大的机器。GCD是Grand Central Dispatch的简称，它是基于C语言的。如果使用GCD，
转载自http://blog.csdn.net/deep_explore/article/details/8144613 通过使用NSOperationQueue实现多线程加载图片，并实现缓存 新建类cc #import <Foundation/Foundation.h>@interface CC : NSOperation{
NSString *url;
NSString *imageName;
UIImage *image;
UIImageView *delegate;}@property (nonatomic,retain) NSString *url;@property (nonatomic,retain)NSString *imageName;@property (nonatomic,retain)UIImage *image;@property (nonatomic,retain)UIImageView *delegate;-(void)main;-(id) initWith:(NSString *)url imageName:(NSString *)imageName delegate:(UIImageView *)delegate;@end@implementation CC@synthesize url,delegate,image,imageName;-(id) initWith:(NSString *)url imageName:(NSString *)imageName delegate:(UIImageView *)delegate{
if (self = [super init]) {
self.url = [url retain];
self.imageName = imageName;
self.delegate = delegate;
}
return self;}-(void) main{
//
NSString *cachefile = [NSTemporaryDirectory() stringByAppendingPathComponent: self.imageName];
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:self.url]];
[data writeToFile:cachefile atomically:YES];
//
self.image = [UIImage imageWithData:data];
[self performSelectorOnMainThread:@selector(ok) withObject:nil waitUntilDone:NO];}-(void)ok{
[self.delegate setImage:self.image]}@end 然后在viewcontroller中调用
//成员对列的初始化
queue=[[NSOperationQueue alloc]init];//图片资源都在数组里面了arry=[NSArray arrayWithObjects:@"http://static2.dmcdn.net/static/video/451/838/44838154:jpeg_preview_small.jpg?20120509163826",
@"http://static2.dmcdn.net/static/video/656/177/44771656:jpeg_preview_small.jpg?20120509154705",
@"http://static2.dmcdn.net/static/video/629/228/44822926:jpeg_preview_small.jpg?20120509181018",
@"http://static2.dmcdn.net/static/video/116/367/44763611:jpeg_preview_small.jpg?20120509101749",
@"http://static2.dmcdn.net/static/video/340/086/44680043:jpeg_preview_small.jpg?20120509180118",
@"http://static2.dmcdn.net/static/video/666/645/43546666:jpeg_preview_small.jpg?20120412153140",
@"http://static2.dmcdn.net/static/video/771/577/44775177:jpeg_preview_small.jpg?20120509183230",
@"http://static2.dmcdn.net/static/video/810/508/44805018:jpeg_preview_small.jpg?20120508125339",
@"http://static2.dmcdn.net/static/video/152/008/44800251:jpeg_preview_small.jpg?20120508103336",
@"http://static2.dmcdn.net/static/video/694/741/35147496:jpeg_preview_small.jpg?20120508111445",
@"http://static2.dmcdn.net/static/video/988/667/44766889:jpeg_preview_small.jpg?20120508130425",
@"http://static2.dmcdn.net/static/video/282/467/44764282:jpeg_preview_small.jpg?20120507130637",
@"http://static2.dmcdn.net/static/video/754/657/44756457:jpeg_preview_small.j
pg?20120507093012",相关推荐：iOS开发 中的 多线程
//程序:可执行文件 //进程:一个正在运行的可执行文件,每个进程都有独立的虚拟内存空间和系统资源,包括端口权限等,并且至少包括一个主线程和任意数量的辅助线程,另外,当一个进程的主线程退出时,这个进程就结束了 //线程:一个独立的代码执行路径(线程是代码执
@"http://static2.dmcdn.net/static/video/831/107/44701138:jpeg_preview_small.jpg?20120506133917",
@"http://static2.dmcdn.net/static/video/411/057/44750114:jpeg_preview_small.jpg?20120507014914",
@"http://static2.dmcdn.net/static/video/894/547/44745498:jpeg_preview_small.jpg?20120509183004",
@"http://static2.dmcdn.net/static/video/082/947/44749280:jpeg_preview_small.jpg?20120507015022",
@"http://static2.dmcdn.net/static/video/833/347/44743338:jpeg_preview_small.jpg?20120509183004",
@"http://static2.dmcdn.net/static/video/683/666/44666386:jpeg_preview_small.jpg?20120505111208",nil］；
在tableview中实现图片的加载-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString *identifity=[NSString
stringWithFormat:@"identify%d%d",indexPath.section,indexPath.row ];
UITableViewCell *cell=(UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:identifity];
if (cell==nil) {
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:identifity];
cell.selectionStyle=UITableViewCellSelectionStyleNone; NSString *filename=[NSString stringWithFormat:@"%d",indexPath.row];
NSLog(@"filename=====%@",filename);
NSString *cachefile=[NSTemporaryDirectory() stringByAppendingPathComponent:filename];
NSLog(@"cachefile=======-----%@",cachefile);
UIImage *Image=[UIImage imageWithContentsOfFile:cachefile];
if (Image) {
cell.imageView.image=Image;
NSLog(@"有缓存，");
}else{
NSLog(@"无缓存，");
NSLog(@"arry===%@",[arry objectAtIndex:indexPath.row]);
CC *o = [[CC alloc] initWith:[[arry retain] objectAtIndex:indexPath.row] imageName:[NSString stringWithFormat:@"%d",indexPath.row] delegate:cell.imageView];
[queue addOperation:o];
cell.imageView.Image=[UIImage imageNamed:@"default.png"];
／／记得arry要retain，要不然滑动时回内存崩溃[[arry retain] objectAtIndex:indexPath.row] 这样写正确｝} 删除图片缓存方法 ＃define K_LOCATION_IMG_COUNT 200+ (void)checkLocationImgAndRemove {
NSString *AppPath=[NSHomeDirectory() stringByAppendingString:@"/Documents/Images/PermanentStore/"];
NSFileManager *manager = [NSFileManager defaultManager];
if([manager fileExistsAtPath:AppPath]) {
NSArray *locationImgArray = [manager contentsOfDirectoryAtPath:AppPath error:nil];
if ([locationImgArray count] > [K_LOCATION_IMG_COUNT intValue]) {
[manager removeItemAtPath:AppPath error:nil];
}
}}@"/Documents/Images/PermanentStore/"自定，是做缓存图片的文件夹路径！ 清除webview中的缓存 http://stackoverflow.com/questions/2523435/how-to-clear-uiwebview-cache
