我正在根据本教程(http://bit.ly/NI9kQe)构建应用程序,该应用程序使用自定义Web API连接到Web服务器。其中一个要求是检测是否已点击“登录”或“注册”按钮。这是使用为接口构建器中的按钮设置的“标记”完成的(注册按钮的标记为1)。
代码块位于btnLoginRegisterTapped方法内部,如下所示(错误发生在该行 - &gt; NSString * command =(sender.tag == 1)?@“register”:@“login”;):< / p>
- (IBAction)btnLoginRegisterTapped:(id)sender {
//form fields validation
if (fldUserName.text.length < 4 || fldPassword.text.length < 4) {
// [UIAlertView error:@"Enter username and password over 4 chars each."];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Opps!!" message:@"Enter username and password over 4 chars each." delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
// optional - add more buttons:
[alert addButtonWithTitle:@"Yes"];
[alert show];
return;
}
//salt the password
NSString* saltedPassword = [NSString stringWithFormat:@"%@%@", fldPassword.text, kSalt];
//prepare the hashed storage
NSString* hashedPassword = nil;
unsigned char hashedPasswordData[CC_SHA1_DIGEST_LENGTH];
//hash the pass
NSData *data = [saltedPassword dataUsingEncoding: NSUTF8StringEncoding];
if (CC_SHA1([data bytes], [data length], hashedPasswordData)) {
hashedPassword = [[NSString alloc] initWithBytes:hashedPasswordData length:sizeof(hashedPasswordData) encoding:NSASCIIStringEncoding];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Opps!!" message:@"Password cannot be reset!" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
// optional - add more buttons:
[alert addButtonWithTitle:@"Yes"];
[alert show];
return;
}
//************ THIS IS WHERE THE ERROR OCCURS *****************//
//check whether it's a login or register
NSString* command = (sender.tag==1)?@"register":@"login";
NSMutableDictionary* params =[NSMutableDictionary dictionaryWithObjectsAndKeys:
command, @"command",
fldUserName.text, @"username",
hashedPassword, @"password",
nil];
//make the call to the web API
[[API sharedInstance] commandWithParams:params
onCompletion:^(NSDictionary *json) {
//handle the response
//result returned
NSDictionary* res = [[json objectForKey:@"result"] objectAtIndex:0];
if ([json objectForKey:@"error"]==nil && [[res objectForKey:@"IdUser"] intValue]>0) {
//success
[[API sharedInstance] setUser: res];
[self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
//show message to the user
[[[UIAlertView alloc] initWithTitle:@"Logged in"
message:[NSString stringWithFormat:@"Welcome %@",[res objectForKey:@"username"] ]
delegate:nil
cancelButtonTitle:@"Close"
otherButtonTitles: nil] show];
} else {
//error
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Opps!!" message:@"Server down? Try Again" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil];
// optional - add more buttons:
[alert addButtonWithTitle:@"Yes"];
[alert show];
return;
}
}];
}
当我尝试构建项目(实际上是工作空间)时,我收到错误:
在'_strong id'
类型的对象上找不到属性'tag'我正在使用xcode 5.0部署iOS7。
谢谢,
答案 0 :(得分:16)
属性语法不能与通用id
类型的变量一起使用。
所以要么通过方法调用sender.tag
或更好替换[sender tag]
,
在方法定义中使用sender
参数的实际类型:
- (IBAction)btnLoginRegisterTapped:(UIButton *)sender { ... }
提示:在Xcode中使用“Control-Drag”创建操作时, 使用“类型”字段中的弹出窗口选择发件人的实际类型。 然后使用正确的参数类型创建action方法。