添加MessageUI。框架并使用下面的代码

#import <MessageUI/MessageUI.h> 

然后:

if ([MFMessageComposeViewController canSendText]) {
  MFMessageComposeViewController *messageComposer =
  [[MFMessageComposeViewController alloc] init];
  NSString *message = @"Your Message here";
  [messageComposer setBody:message];
  messageComposer.messageComposeDelegate = self;
  [self presentViewController:messageComposer animated:YES completion:nil];
}

以及委托方法-

- (void)messageComposeViewController:(MFMessageComposeViewController *)controller
             didFinishWithResult:(MessageComposeResult)result {
      [self dismissViewControllerAnimated:YES completion:nil];
 }

[[UIApplication sharedApplication]openURL:[NSURL URLWithString:@"sms:number"]] 

这将是最好和最简单的方法。

//Add the Framework in .h file

#import <MessageUI/MessageUI.h>
#import <MessageUI/MFMailComposeViewController.h>

//Set the delegate methods

UIViewController<UINavigationControllerDelegate,MFMessageComposeViewControllerDelegate>

//add the below code in .m file


- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];

    MFMessageComposeViewController *controller = 
    [[[MFMessageComposeViewController alloc] init] autorelease];

    if([MFMessageComposeViewController canSendText])
    { 
        NSString *str= @"Hello";
        controller.body = str;
        controller.recipients = [NSArray arrayWithObjects:
                                 @"", nil];
        controller.delegate = self;
        [self presentModalViewController:controller animated:YES];  
    }


}

- (void)messageComposeViewController:
(MFMessageComposeViewController *)controller
                 didFinishWithResult:(MessageComposeResult)result 
{
    switch (result)
    {
        case MessageComposeResultCancelled:  
            NSLog(@"Cancelled");    
            break; 
        case MessageComposeResultFailed:
            NSLog(@"Failed");
            break;   
        case MessageComposeResultSent:      
            break; 
        default:  
            break;  
    }  
    [self dismissModalViewControllerAnimated:YES]; 
}

这是一个教程，它完全是你正在寻找的:MFMessageComposeViewController。

http://blog.mugunthkumar.com/coding/iphone-tutorial-how-to-send-in-app-sms/

从本质上讲:

MFMessageComposeViewController *controller = [[[MFMessageComposeViewController alloc] init] autorelease];
if([MFMessageComposeViewController canSendText])
{
    controller.body = @"SMS message here";
    controller.recipients = [NSArray arrayWithObjects:@"1(234)567-8910", nil];
    controller.messageComposeDelegate = self;
    [self presentModalViewController:controller animated:YES];
}

还有文档的链接。

https://developer.apple.com/documentation/messageui/mfmessagecomposeviewcontroller

如果你想在你自己的应用程序中显示创建和发送消息，你需要使用MFMessageComposeViewController。

否则，您可以使用sharedApplication方法。

您可以使用sms:[目标电话号码]URL打开sms应用程序，但没有指示如何用文本预填充sms正文。