关于在多个UItextield切换焦点

 1 -(BOOL)textFieldShouldReturn:(UITextField *)textField{//传入的是当前使用的textField
 2     [self switchtextField:textField];
 3     return YES;
 4 }
 5 
 6 //在弹出键盘之前检查输入状态，只有一个有输入那么按键就是Next，2个完成输入就Done
 7 - (void)textFieldDidBeginEditing:(UITextField *)textField{
 8     if ([textField isEqual:self.textFieldTitle]) {
 9         textField.returnKeyType = [self.textFieldSubTitle.text length] ? UIReturnKeyDone :UIReturnKeyNext;
10     }else if([textField isEqual:self.textFieldSubTitle]){
11         textField.returnKeyType = textField.returnKeyType = [self.textFieldTitle.text length] ? UIReturnKeyDone :UIReturnKeyNext;
12     }
13 }
14 
15 -(void)switchtextField :(UITextField*) textField {
16     NSUInteger titLenth = [self.textFieldTitle.text length];
17     NSUInteger  subLenth = [self.textFieldSubTitle.text length];
18     
19     if ([self.textFieldTitle isFirstResponder]) {
20         [self.textFieldSubTitle becomeFirstResponder];
21     }else if([self.textFieldSubTitle isFirstResponder]){
22         [self.textFieldTitle becomeFirstResponder];
23     }
24     
25     if (titLenth && subLenth) {
26         [textField resignFirstResponder];
27         BOOL CanSegue = [self shouldPerform:kUNWIND_ID];
28         if (CanSegue)
29             [self performSegueWithIdentifier:kUNWIND_ID sender:nil];
30         
31     }
32 }
33 
34 -(BOOL) shouldPerform:(NSString *)identifier  {
35     if ([identifier isEqualToString:kUNWIND_ID]) {
36         if (!self.image) {
37             [self alert:@"No Photo taken!"];
38             return NO;
39         }else if(![self.textFieldTitle.text length] || ![self.textFieldSubTitle.text length]){
40             [self.textFieldTitle.text length] ? [self alert:@"SubTitle required!"]   :
41             [self.textFieldSubTitle.text length] ?  [self alert:@"Title required!"]  :
42             [self alert:@"Title and SubTitle required"] ;
43             return NO;
44         }else{
45             return YES;
46         }
47     }else{
48         return NO;
49     }
50 
51 }