我正在尝试执行三个不同的 JSON 连接，以使用来自三个不同 MySQL 表的标记填充 mapView。
这是我现在要做的代码。为了测试连接，我记录了 didReceiveData 方法，但编译器光标没有到达该方法，当然，任何标记都显示在 map 上。
恳请您查看我的代码并告诉我我遗漏了什么或做错了什么。谢谢。
- (void)viewDidLoad
{
[super viewDidLoad];
self.title = @"Geolocalización";
//carga de datos JSON
//network activity indicator showed during downloading data
//PROCESSING FIRST CONNECTION
first_connection_url = [NSURL URLWithString:@"http://mujercanariasigloxxi.appgestion.eu/app_php_files/empresastodaslist.php"];
NSURLRequest *first_connection_request = [NSURLRequest requestWithURL:first_connection_url];
NSURLConnection *first_connection=[[NSURLConnection alloc]initWithRequest:first_connection_request delegate:self];
//PROCESSING SECOND CONNECTION
second_connection_url = [NSURL URLWithString:@"http://mujercanariasigloxxi.appgestion.eu/app_php_files/centrostodoslist.php"];
NSURLRequest *second_connection_request = [NSURLRequest requestWithURL:second_connection_url];
NSURLConnection *second_connection=[[NSURLConnection alloc]initWithRequest:second_connection_request delegate:self];
//PROCESSING THIRD CONNECTION
third_connection_url = [NSURL URLWithString:@"http://mujercanariasigloxxi.appgestion.eu/app_php_files/eventostodoslist.php"];
NSURLRequest *thrid_connection_request = [NSURLRequest requestWithURL:third_connection_url];
NSURLConnection *third_connection=[[NSURLConnection alloc]initWithRequest:second_connection_request delegate:self];
}
//methods to perform the connection and population of data
-(void)connection: (NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
if(connection==first_connection){
data_for_first_connection = [[NSMutableData alloc]init];
}
else if(connection==second_connection){
data_for_second_connection = [[NSMutableData alloc]init];
}
else if(connection==third_connection){
data_for_third_connection = [[NSMutableData alloc]init];
}
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)thedata
{
if(connection==first_connection){
[data_for_first_connection appendData:thedata];
NSLog(@"CONEXION 1 AQUI");
}
else if(connection==second_connection){
[data_for_second_connection appendData:thedata];
NSLog(@"CONEXION 2 AQUI");
}
else if(connection==third_connection){
[data_for_third_connection appendData:thedata];
NSLog(@"CONEXION 3 AQUI");
}
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
//if data received network indicator not visible
[UIApplication sharedApplication].networkActivityIndicatorVisible=NO;
if(connection==first_connection) {
categorias_first = [NSJSONSerialization JSONObjectWithData:data_for_first_connection options:0 error:nil];
}
else if(connection==second_connection){
categorias_second = [NSJSONSerialization JSONObjectWithData:data_for_second_connection options:0 error:nil];
}
else if(connection==third_connection){
// PROCESS TO BE DONE FOR SECOND CONNECTION
categorias_third = [NSJSONSerialization JSONObjectWithData:data_for_third_connection options:0 error:nil];
}
// Create a GMSCameraPosition that tells the map to display the
// coordinate -33.86,151.20 at zoom level 6.
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:27.9847
longitude:-15.5953
zoom:9];
mapView_ = [GMSMapView mapWithFrame:CGRectZero camera:camera];
mapView_.myLocationEnabled = YES;
mapView_.delegate = self;
self.view = mapView_;
UISegmentedControl *mainSegment = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Ofertas", @"Cursos", @"Eventos", nil]];
[mainSegment setSegmentedControlStyle:UISegmentedControlStyleBar];
mainSegment.frame = CGRectMake(20,80, 280, 43);
//self.navigationItem.titleView = mainSegment;
//mainSegment.selectedSegmentIndex = nil;
[mainSegment addTarget:self action:@selector(mainSegmentControl:) forControlEvents: UIControlEventValueChanged];
[self.view addSubview:mainSegment];
}
用于测试应用程序的更新代码。
我已经更新了我的代码来测试它，现在我只使用两个连接。在记录结果时，我检测到数组 categoria(在 first_connection)和 categoria2(在 second_connection)是从同一个 JSON 文件(从 first_connection)填充的:
- (void)viewDidLoad
{
[super viewDidLoad];
self.title = @"Geolocalización";
//carga de datos JSON
//network activity indicator showed during downloading data
[UIApplication sharedApplication].networkActivityIndicatorVisible=YES;
//URL definition where php file is hosted
//conexion1
url = [NSURL URLWithString:@"http://mujercanariasigloxxi.appgestion.eu/app_php_files/empresastodaslist.php"];
request = [NSURLRequest requestWithURL:url];
first_connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
//conexion2
url2 = [NSURL URLWithString:@"http://mujercanariasigloxxi.appgestion.eu/app_php_files/centrostodoslist.php"];
request2 = [NSURLRequest requestWithURL:url];
second_connection = [[NSURLConnection alloc] initWithRequest:request2 delegate:self];
}
//methods to perform the connection and population of data
-(void)connection: (NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
if ([connection isEqual:first_connection]){
NSLog(@"FIRST CONNECTION RESPONSE");
data = [[NSMutableData alloc]init];
}
if ([connection isEqual:second_connection]){
NSLog(@"SECOND CONNECTION RESPONSE");
data2 = [[NSMutableData alloc]init];
}
NSLog(@"ESTOY EN DIDRECEIVERESPONSE");
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)thedata
{
if ([connection isEqual:first_connection]){
NSLog(@"FIRST CONNECTION RECEIVED");
[data appendData:thedata];
}
if ([connection isEqual:second_connection]){
NSLog(@"SECOND CONNECTION RECEIVED");
[data2 appendData:thedata];
}
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
//if data received network indicator not visible
[UIApplication sharedApplication].networkActivityIndicatorVisible=NO;
//array waterfalls populated via JSON from database
if ([connection isEqual:first_connection]){
categorias = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
NSLog(@"DATA1 = %@",categorias);
}
if ([connection isEqual:second_connection]){
categorias2 = [NSJSONSerialization JSONObjectWithData:data2 options:0 error:nil];
NSLog(@"DATA2 = %@",categorias2);
}
NSLog(@"NUMERO DE EMPRESAS OPCION1= %lu"
, (unsigned long)[categorias count]);
NSLog(@"NUMERO DE EMPRESAS OPCION2= %lu"
, (unsigned long)[categorias2 count]);
// Create a GMSCameraPosition that tells the map to display the
// coordinate -33.86,151.20 at zoom level 6.
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:27.9847
longitude:-15.5953
zoom:9];
mapView_ = [GMSMapView mapWithFrame:CGRectZero camera:camera];
mapView_.myLocationEnabled = YES;
mapView_.delegate = self;
self.view = mapView_;
UISegmentedControl *mainSegment = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Ofertas", @"Cursos", @"Eventos", nil]];
[mainSegment setSegmentedControlStyle:UISegmentedControlStyleBar];
mainSegment.frame = CGRectMake(20,80, 280, 43);
//self.navigationItem.titleView = mainSegment;
//mainSegment.selectedSegmentIndex = nil;
[mainSegment addTarget:self action:@selector(mainSegmentControl:) forControlEvents: UIControlEventValueChanged];
[self.view addSubview:mainSegment];
}
最佳答案
我看到了几个问题。首先，您的连接、firstConnection、secondConnection 等被创建为局部变量，因此一旦 viewDidLoad 超出范围，它们就会被释放。当您检查委托(delegate)方法中的相等性时，它们此时将为 nil。您应该为这些连接创建 ivars 或属性。此外，您不应使用“==”来比较对象，而应使用 isEqual:。
else if([connection isEqual:third_connection]){
关于ios - 用于在 mapView 上显示标记的 JSON 连接，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22342458/