显示图片加载时的进度条

#import "ViewController.h"

#import "UIImageView+WebCache.h"

@interface ViewController ()

@property (nonatomic,strong) UIImageView *imv;

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.imv = [[UIImageView alloc]initWithFrame:self.view.bounds];

[self.view addSubview:self.imv];

__block UIProgressView *pv;

[self.imv sd_setImageWithURL:[NSURL URLWithString:@"http://p1.pichost.me/i/40/1639665.png"] placeholderImage:nil options:SDWebImageCacheMemoryOnly  progress:^(NSInteger receivedSize, NSInteger expectedSize) {

pv = [[UIProgressView alloc]initWithProgressViewStyle:(UIProgressViewStyleDefault)];

pv.frame = CGRectMake(0, 0, 400, 20);

pv.center = self.view.center;

NSLog(@"%ld,%ld",receivedSize,expectedSize);

float currentProgress = (float)receivedSize/(float)expectedSize;

pv.progress = currentProgress;

[self.imv addSubview:pv];

} completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {

[pv removeFromSuperview];

}];

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}