UIImageView加载网络图片，NSOperationQueue来异步加载图片

#import "newDetailViewController.h"#import "Common.h"#import "newObject.h"#import "NetRequest.h"#import <UIKit/UIKitDefines.h>@interface newDetailViewController ()<UIWebViewDelegate>{    UILabel *GWDetailTitleText;    UILabel *GWDetailTitleText1;    UITextView *GWDetailContentText;        UIImageView *imageview;    NSURL *url;        UIView *opaqueview;    UIActivityIndicatorView *activityIndicator;    }@end@implementation newDetailViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7) {            self.view.bounds = CGRectMake(0, -20, self.view.frame.size.width, self.view.frame.size.height );        }    }    return self;}- (void)viewDidLoad{         [UIApplication sharedApplication].statusBarHidden = YES;    [super viewDidLoad];    //[self initView];}-(void)initView{        UIButton *loginButton = [[UIButton alloc]initWithFrame:CGRectMake(SCREEN_WIDTH - 40, 0, 40, 30)];    [loginButton setTitle:@"返回" forState:UIControlStateNormal];    loginButton.titleLabel.textColor =[UIColor blackColor];    [loginButton addTarget:self action:@selector(backtofather) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:loginButton];        GWDetailTitleText = [[UILabel alloc]initWithFrame:CGRectMake(10, 30, SCREEN_WIDTH - 20, 40)];    GWDetailTitleText.textAlignment = NSTextAlignmentCenter;    GWDetailTitleText.numberOfLines = 0;    GWDetailTitleText.lineBreakMode = UILineBreakModeCharacterWrap;    [self.view addSubview:GWDetailTitleText];                GWDetailTitleText1 = [[UILabel alloc]initWithFrame:CGRectMake(10, 70, SCREEN_WIDTH - 20, 20)];    GWDetailTitleText1.textAlignment = NSTextAlignmentLeft;    [self.view addSubview:GWDetailTitleText1];            web = [[UIWebView alloc]initWithFrame:CGRectMake(10, 100, SCREEN_WIDTH - 20, self.view.bounds.origin.y + self.view.bounds.size.height - 110)];    web.scalesPageToFit = YES;    web.delegate = self;    [[web layer] setCornerRadius:10];    [web setClipsToBounds:YES];    web.scalesPageToFit = NO;    for (id subview in web.subviews)    {        if ([[subview class] isSubclassOfClass: [UIScrollView class]])        {            ((UIScrollView *)subview).bounces = NO;        }    }    web.backgroundColor = [UIColor whiteColor];    [self.view addSubview:web];            //    GWDetailContentText = [[UITextView alloc]initWithFrame:CGRectMake(10, 100, SCREEN_WIDTH - 20, self.view.bounds.origin.y + self.view.bounds.size.height - 110)];//    GWDetailContentText.layer.borderWidth = 1;//    GWDetailContentText.editable = NO;//    [self.view addSubview:GWDetailContentText];}-(void)setchoicedDate:(newObject *)myarray{    [self initView];     MyLog(@"%@  ", myarray );    //MyLog(@"%@", myarray[0]);//[@"rel_title"]    GWDetailTitleText.text = myarray.rel_title;        NSString *date =[[NSString alloc]initWithString:myarray.rel_date];    date = [date substringToIndex:10];    NSString *mystring = [NSString stringWithFormat:@"发布人:%@ 日期:%@",myarray.rel_user,date];    GWDetailTitleText1.text = mystring;    MyLog(@"%@",myarray.rel_picpath);    if (![myarray.rel_picpath isEqualToString:@"null"]) {        url = [NSURL URLWithString:[NSString stringWithFormat:@"%@%@",@"http://www.xf0573.com",myarray.rel_picpath]];        imageview = [[UIImageView alloc]initWithFrame:CGRectMake(80, 0, 160, 120)];        imageview.layer.masksToBounds = YES;        imageview.layer.cornerRadius = 5.0f;        [imageview setBackgroundColor:[UIColor grayColor]];        imageview.image = [UIImage imageNamed:@"moren.png"];        [web addSubview:imageview];                opaqueview = [[ UIView   alloc]  initWithFrame: CGRectMake(0, 0,  160, 120)];        activityIndicator  = [[UIActivityIndicatorView   alloc]  initWithFrame: CGRectMake( 0, 0,  160, 120)];        [ opaqueview setBackgroundColor:[UIColor blackColor]];        [ opaqueview setAlpha:0.6 ];        [ imageview addSubview: opaqueview];        [ opaqueview addSubview: activityIndicator];        [ activityIndicator startAnimating ];        opaqueview.hidden  = NO ;                web1 = [[UIWebView alloc]initWithFrame:CGRectMake(10, 120, SCREEN_WIDTH - 20, self.view.bounds.origin.y + self.view.bounds.size.height - web.frame.origin.y - 130)];        web1.scalesPageToFit = YES;        web1.delegate = self;        [[web1 layer] setCornerRadius:10];        [web1 setClipsToBounds:YES];        web1.scalesPageToFit = NO;        for (id subview in web1.subviews)        {            if ([[subview class] isSubclassOfClass: [UIScrollView class]])            {                ((UIScrollView *)subview).bounces = NO;            }        }        web1.backgroundColor = [UIColor whiteColor];        [web1 loadHTMLString:myarray.rel_content baseURL:nil];        [web addSubview:web1];                        NSOperationQueue *operationQueue = [[NSOperationQueue alloc] init];        NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(downloadImage) object:nil];        [operationQueue addOperation:op];                                //[web loadRequest:req];    }else if ([myarray.rel_picpath isEqualToString:@"null"])    {        [web loadHTMLString:myarray.rel_content baseURL:nil];    //GWDetailContentText.text = myarray.rel_content;    }}- (void)downloadImage{        UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];    imageview.image = image;        [activityIndicator stopAnimating];    opaqueview.hidden  = YES ;}-(void)backtofather{    [self dismissModalViewControllerAnimated:YES];}@end