連接確實完成接收數據后，如何更改ios視圖？

Question

在此應用程序中，當用戶按下按鈕時，URL請求將被發送到服務器，並且一些相應的數據將被應用程序接收。

我的問題是我想完全從服務器接收數據，並且當連接完成接收數據時，請更改視圖並將接收到的數據傳遞給另一個視圖。

數據轉換后，我收到錯誤消息，應用崩潰。

我嘗試了這種方法，但不知道該怎么做。
解決問題並編輯代碼

 #import "ViewController.h"
@interface ViewController ()
//@property (nonatomic, strong) NSMutableData *responseData;

@end

@implementation ViewController
@synthesize responseData;
@synthesize myTableView;
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(@"viewdidload");
}
- (void)didReceiveMemoryWarning
{
  [super didReceiveMemoryWarning];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

   NSLog(@"Response received From the server.");
  [self.responseData setLength:0];
}
  - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

  NSLog(@"appending data to the response object.");
  [self.responseData appendData:data];

}
 - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {

   NSLog(@"didFailWithError");
   NSLog([NSString stringWithFormat:@"Connection failed: %@", [error description]]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
     NSLog(@"Loading data succeeded! Received %d bytes of data", 
       [self.responseData length]);
     //call the converter to convert the received 
     //Data to Json Packet and save to variable
     [self convertDataToJson];
      [self changePage];

 }
 -(void)changePage {
      resultsTableViewController *myTableView = [[resultsTableViewController  alloc]init];
       myTableView.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
        myTableView=[myTableView init];
        [self presentViewController:myTableView animated:YES completion:NULL];

 }


-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
  {
   resultsTableViewController *mytable = [segue destinationViewController];
   NSMutableArray * response = self.responseArray;
   mytable.responseArray = response;

   }

- (IBAction)get:(id)sender {


  //making an instance of data query object and passing the word and dictionary selection to it.
   if ( ![[searchField text]isEqualToString:@""] )
   {
       word = @”test”
       [self makeRequestForWord:word withDictionaryName:@""];
       // NSData *query = [word dataUsingEncoding:NSUTF8StringEncoding];
  }
 }



-(void)makeRequestForWord:(NSString*)word withDictionaryName:(NSString*)dicSelect;
{

    //creating URL Request Object using given URL object.
    //It requests data using nsConnection

}


- (void)convertDataToJson
{
// some conversion and save into responseDATA
}

- (void)viewDidUnload {
   [super viewDidUnload];
}
@end

然后在與segue相關的功能中，將對象發送到下一個視圖。

Answer 1

您不應該在connectionDidFinishLoading中顯示視圖控制器：因為似乎已經為控制器設置了segue －因為您尚未創建myTable（在.h文件中聲明未創建，所以它在那里崩潰了）它）。 segue將創建您的控制器的實例，因此您應該在connectionDidFinishLoading中調用performSegueWithIdentifier：sender :：

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
     NSLog(@"Loading data succeeded! Received %d bytes of data", 
       [self.responseData length]);
     //call the converter to convert the received 
     //Data to Json Packet and save to variable
     [self convertDataToJson];

     [self performSegueWithIdentifier:@"MyIdentifier" sender:self];
 }