第三方的等待指示器，MBProgressHUD就是第三方提供的等待指示器框架。下面是MBProgressHUD提供的等待指示器样式，它们基 本可以分为：未知结束时间和已知结束时间两大类等待指示器，在MBProgressHUD中可以为等待指示器添加标签和详细标签
MBProgressHUD的下载地址是https://github.com/matej/MBProgressHUD，我们将下载的源 文件中的MBProgressHUD.h和MBProgressHUD.m拷贝到自己的工程中，MBProgressHUD依赖的框架 有：Foundation.framework、UIKit.framework和CoreGraphics.framework，我们需要将这些框架添 加到工程中。
我们为应用添加MBProgressHUD等待指示器，修改主视图控制器MasterViewController.m的startRequest方法代码如下，注意加粗部分：
-(void)startRequest
{
//初始化MBProgressHUD
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
hud.mode = MBProgressHUDModeCustomView;
hud.labelText = @”Loading”;
NSString *strURL = [[NSString alloc]
initWithFormat:@”http://iosbook3/mynotes/webservice.php”];
NSURL *url = [NSURL URLWithString:[strURL URLEncodedString]];
NSString *post;
if (action == ACTION_QUERY) {//查询处理
post = [NSString stringWithFormat:@"email=%@&type=%@&action=%@",
@"<你的iosbook1.com用户邮箱>",@"JSON",@"query"];
} else if (action == ACTION_REMOVE) {//删除处理
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
NSMutableDictionary* dict = self.listData[indexPath.row];
post = [NSString stringWithFormat:@"email=%@&type=%@&action=%@&id=%@",
@"<你的iosbook1.com用户邮箱>",@"JSON",@"remove",[dict objectForKey:@"ID"]];
}
NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
[request setHTTPBody:postData];
NSURLConnection *connection = [[NSURLConnection alloc]
initWithRequest:request delegate:self];
if (connection) {
_datas = [NSMutableData new];
}
}
-(void) connection:(NSURLConnection *)connection didFailWithError: (NSError *)error {
NSLog(@”%@”,[error localizedDescription]);
[MBProgressHUD hideHUDForView:self.view animated:YES];
}
- (void) connectionDidFinishLoading: (NSURLConnection*) connection {
NSLog(@”请求完成…”);
NSDictionary* dict = [NSJSONSerialization JSONObjectWithData:_datas
options:NSJSONReadingAllowFragments error:nil];
if (action == ACTION_QUERY) {//查询处理
[self reloadView:dict];
} else if (action == ACTION_REMOVE) {//删除处理
NSString *message = @”操作成功。”;
NSNumber *resultCodeObj = [dict objectForKey:@"ResultCode"];
if ([resultCodeObj integerValue] < 0) {
message = [resultCodeObj errorMessage];
}
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@”提示信息”
message:message
delegate:nil
cancelButtonTitle:@”OK”
otherButtonTitles: nil];
[alertView show];
//重新查询
action = ACTION_QUERY;
[self startRequest];
}
[MBProgressHUD hideHUDForView:self.view animated:YES];
}