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甚至为了performance，所有的加载操作都在后台完成，一定要重用：
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在iOS开发中利用GCD进行多线程编程
iOS开发中使用NSOperationQueue进行多线程操作
避免后台加载完成多个资源之后集中到达占用UI线程的处理时间太长。
这一点可以通过dispatch或者performSelectorInBackground或者NSOperationQueue来实现。
创建cell一般是很慢的。
重用cell解决办法
主要要做到一下几个方面，且在每个操作完成之后进行强制等待。
这一点可以通过NSOperationQueue来实现。见：
除了UI部分，可以用usleep(int microSeconds)来解决，将资源到UI的展现过程放在队列中逐个执行，可以在view创建之初就创建足够多的cell在重用队列中
，然后把两个MBProgressHUD.h和MBProgressHUD.m放到自己的项目就可以了。这里有一个小Demo可以参考一下。
头文件部分：
#import UIKit/UIKit.h#import "MBProgressHUD.h"@interface ViewController : UIViewController{ MBProgressHUD *HUD;}- (IBAction)showTextDialog:(id)sender; //文本提示框，默认情况下- (IBAction)showProgressOne:(id)sender; //第一种加载提示框- (IBAction)showProgressTwo:(id)sender; //第二种加载提示框- (IBAction)showProgressThree:(id)sender; //第三种加载提示框- (IBAction)showCustomDialog:(id)sender; //自定义提示框，显示打钩效果- (IBAction)showAllTextDialog:(id)sender; //显示纯文本提示框@end
实现文件部分
#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad{ [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning{ [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}- (IBAction)showTextDialog:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.dimBackground = YES; //把当前的view置于后台 HUD.labelText = @"请稍等"; //显示对话框 [HUD showAnimated:YES whileExecutingBlock:^{ sleep(3); } completionBlock:^{ }];}- (IBAction)showProgressOne:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.labelText = @"正在加载"; HUD.mode = MBProgressHUDModeDeterminate; //HUD.mode = MBProgressHUDModeAnnularDeterminate; [HUD showAnimated:YES whileExecutingBlock:^{ float progress = 0.0f; while (progress 1.0f) { progress += 0.01f; HUD.progress = progress; usleep(5000); } } completionBlock:^{ [HUD removeFromSuperview]; [HUD release]; HUD = nil; }];}- (IBAction)showProgressTwo:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.labelText = @"正在加载"; HUD.mode = HUD.mode = MBProgressHUDModeAnnularDeterminate; [HUD showAnimated:YES whileExecutingBlock:^{ float progress = 0.0f; while (progress 1.0f) { progress += 0.01f; HUD.progress = progress; usleep(5000); } } completionBlock:^{ [HUD removeFromSuperview]; [HUD release]; HUD = nil; }];}- (IBAction)showProgressThree:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.labelText = @"正在加载"; HUD.mode = MBProgressHUDModeDeterminateHorizontalBar; [HUD showAnimated:YES whileExecutingBlock:^{ float progress = 0.0f; while (progress 1.0f) { progress += 0.01f; HUD.progress = progress; usleep(5000); } } completionBlock:^{ [HUD removeFromSuperview]; [HUD release]; HUD = nil; }];}- (IBAction)showCustomDialog:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.labelText = @"操作成功"; HUD.mode = MBProgressHUDModeCustomView; HUD.customView = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Checkmark"]] autorelease]; [HUD showAnimated:YES whileExecutingBlock:^{ sleep(2); } completionBlock:^{ [HUD removeFromSuperview]; [HUD release]; HUD = nil; }];}- (IBAction)showAllTextDialog:(id)sender { HUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:HUD]; HUD.labelText = @"操作成功"; HUD.mode = MBProgressHUDModeText; HUD.customView = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Checkmark"]] autorelease]; [HUD showAnimated:YES whileExecutingBlock:^{ sleep(2); } completionBlock:^{ [HUD removeFromSuperview]; [HUD release]; HUD = nil; }]; }- (void)dealloc { [super dealloc];}@end
