block about basic

1.转载 

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{ 

// Show the HUD in the main tread

dispatch_async(dispatch_get_main_queue(), ^{ 

// No need to hod onto (retain)

MBProgressHUD *mbp = [MBProgressHUD showHUDAddedTo:self animated:YES];

mbp.labelText = @"   解压中,请等待...   ";

});

//解压代码 

dispatch_async(dispatch_get_main_queue(), ^{

[MBProgressHUD hideHUDForView:self animated:YES];

});

});