按下按钮时如何撤消UITextField？

Question

我在按下按钮时在创建UITextField时使用数组。 我想添加一个新按钮，撤消功能。 当我按下“撤消”按钮时，我创建的最后一个UITextField将被删除。

在我的ViewController.h上

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UITextFieldDelegate>
{

    NSMutableArray *textfieldform;
    UITextField *textField1;
}

@property (nonatomic) NSInteger text1;

@property (nonatomic, retain) NSMutableArray *textfieldform;
@property (nonatomic, readwrite) int yOrigin;
@property (nonatomic, readwrite) int xOrigin;


-(IBAction) textFieldcreating;
-(IBAction) undo;


@end

在我的ViewController.m上

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

@synthesize text1, textfieldform, yOrigin, xOrigin;


- (void)viewDidLoad
{
    [super viewDidLoad];
    //textfieldform = [[NSMutableArray alloc] init];
    // Do any additional setup after loading the view, typically from a nib.
    textfieldform = [NSMutableArray arrayWithCapacity:0];
    yOrigin = 0;
    xOrigin = 10;

}


-(IBAction)textFieldcreating{

    textField1 = [[UITextField alloc] initWithFrame:CGRectMake(xOrigin, yOrigin, 100, 40)];
    textField1.borderStyle = UITextBorderStyleRoundedRect;
    textField1.font = [UIFont systemFontOfSize:15];
    textField1.placeholder = @"enter text";
    textField1.autocorrectionType = UITextAutocorrectionTypeNo;
    textField1.keyboardType = UIKeyboardTypeDefault;
    textField1.returnKeyType = UIReturnKeyDone;
    textField1.clearButtonMode = UITextFieldViewModeWhileEditing;
    textField1.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;    
    textField1.delegate = self;

    [textfieldform addObject:textField1];
    [self.view addSubview:textField1];
    yOrigin = yOrigin + 40 + 10; 
    xOrigin = xOrigin + 20 + 10; 
    //old yorigin + btn height + y offset

}

-(IBAction)undo{
    if ([textfieldform count]>0) {
        [textfieldform removeLastObject];
        [textField1 removeFromSuperview];
    }
}


- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{ 

    NSLog(@"textFieldShouldBeginEditing");
    return YES;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField{           

    NSLog(@"textFieldDidBeginEditing");
    [textField1  setBackgroundColor:[UIColor colorWithRed:(248/255.0) green:(248/255.0) blue:(255/255.0) alpha:1.0]];
    textField1.borderStyle = UITextBorderStyleRoundedRect;
}
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField{

    NSLog(@"textFieldShouldEndEditing");
    textField.backgroundColor = [UIColor clearColor];
    return YES;
}
- (void)textFieldDidEndEditing:(UITextField *)textField{

    NSLog(@"textFieldDidEndEditing");
    [textField1  setBackgroundColor:[UIColor clearColor]];
    textField1.borderStyle = UITextBorderStyleNone;
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

    NSLog(@"textField:shouldChangeCharactersInRange:replacementString:");

    if ([string isEqualToString:@"#"]) {
        return NO;
    }
    else {
        return YES;
    }

}
- (BOOL)textFieldShouldClear:(UITextField *)textField{

    NSLog(@"textFieldShouldClear:");
    return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{

    NSLog(@"textFieldShouldReturn:");

    if (textField.tag == 1) {
        textField1 = (UITextField *)[self.view viewWithTag:2];
        [textField1 becomeFirstResponder];
    }
    else {
        [textField resignFirstResponder];
    }

    return YES;
}




@end

Answer 1

根据数组中每个文本字段的indexPath为其分配一个标签。

-(IBAction)textFieldcreating{

UITextField *textField1 = [[UITextField alloc] initWithFrame:CGRectMake(xOrigin, yOrigin, 100, 40)];
textField1.borderStyle = UITextBorderStyleRoundedRect;
textField1.font = [UIFont systemFontOfSize:15];
textField1.placeholder = @"enter text";
textField1.autocorrectionType = UITextAutocorrectionTypeNo;
textField1.keyboardType = UIKeyboardTypeDefault;
textField1.returnKeyType = UIReturnKeyDone;
textField1.clearButtonMode = UITextFieldViewModeWhileEditing;
textField1.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;    
textField1.delegate = self;

textField1.tag = textfieldform.count;

[textfieldform addObject:textField1];
[self.view addSubview:textField1];
yOrigin = yOrigin + 40 + 10; 
xOrigin = xOrigin + 20 + 10; 
//old yorigin + btn height + y offset

}

比您的不定行为应该有类似

-(IBAction)undo{  //Should also check here if you actually have an object at that index path. (for example if there are no text fields created yet)

UITextField *textField = (UITextField *)[self.view viewWithTag:textfieldform.count - 1];
textField = nil;
[textField removeFromSuperview];
[textfieldform removeLastObject];

}

Answer 2

由于您将textFields添加到数组中，因此只需从该数组中获取最后一个对象并将其从其超级视图中删除即可。

- (IBAction)undo:(id)sender {
    UITextField *textFieldToRemove = [textfieldform lastObject];
    if (textFieldToRemove) {
        [textfieldform removeObject:textFieldToRemove];
        [textFieldToRemove removeFromSuperview];
    }
}