将 UIToolbar 添加到某些文本字段的输入附件视图

在我寻找我的第一个 iPhone 应用程序时，我发布了有关处理 iOS 键盘上的返回键的正确方法。现在我需要找出键盘上方的工具栏，其中包含上一个/下一个和完成按钮。我一直在使用以下网站的示例：输入配件视图 http://gabriel-tips.blogspot.com/2011/05/input-accessory-view-how-to-add-extra.html

该示例有效，但我想使用 UIToolbar 和 UIBarButtonItem's 而不仅仅是带有按钮的常规视图。我尝试过各种组合，但还没有成功。这是我到目前为止所拥有的。

Header:

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UITextFieldDelegate>
{
    UITextField* txtActiveField;
    UIToolbar* keyboardToolbar;
    UIBarButtonItem* btnDone;
    UIBarButtonItem* btnNext;
    UIBarButtonItem* btnPrev;
}

@property (nonatomic, strong) IBOutlet UITextField* firstNameTextField;
@property (nonatomic, strong) IBOutlet UITextField* lastNameTextField;
@property (nonatomic, strong) IBOutlet UITextField* cityTextField;

@property (nonatomic, strong) UITextField* txtActiveField;
@property (nonatomic, strong) UIToolbar* keyboardToolbar;
@property (nonatomic, strong) UIBarButtonItem* btnDone;
@property (nonatomic, strong) UIBarButtonItem* btnNext;
@property (nonatomic, strong) UIBarButtonItem* btnPrev;

-(void)createInputAccessoryView;

@end

Source:

#import "ViewController.h"

@implementation ViewController

@synthesize firstNameTextField = _firstNameTextField;
@synthesize lastNameTextField = _lastNameTextField;
@synthesize cityTextField = _cityTextField;

@synthesize txtActiveField = _txtActiveField;
@synthesize keyboardToolbar = _keyboardToolbar;
@synthesize btnDone = _btnDone;
@synthesize btnNext = _btnNext;
@synthesize btnPrev = _btnPrev;

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createInputAccessoryView];
}

- (void)viewDidUnload
{
    [self setFirstNameTextField:nil];
    [self setLastNameTextField:nil];
    [self setCityTextField:nil];

    [self setTxtActiveField:nil];
    [self setKeyboardToolbar:nil];
    [self setBtnDone:nil];
    [self setBtnNext:nil];
    [self setBtnPrev:nil];

    [super viewDidUnload];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return YES;
}

-(void)gotoPrevTextfield
{
    if (self.txtActiveField == self.firstNameTextField)
    {
        return;
    }
    else if (self.txtActiveField == self.lastNameTextField)
    {
        [self.firstNameTextField becomeFirstResponder];
    }
    else if (self.txtActiveField == self.cityTextField)
    {
        [self.lastNameTextField becomeFirstResponder];
    }           
}

-(void)gotoNextTextfield
{
    if (self.txtActiveField == self.firstNameTextField)
    {
        [self.lastNameTextField becomeFirstResponder];
    }
    else if (self.txtActiveField == self.lastNameTextField)
    {
        [self.cityTextField becomeFirstResponder];
    }
    else if (self.txtActiveField == self.cityTextField)
    {
        return;
    }           
}

-(void)doneTyping
{
    [self.txtActiveField resignFirstResponder];
}

-(void)createInputAccessoryView
{
    self.keyboardToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 44)];
    self.keyboardToolbar.barStyle = UIBarStyleBlackTranslucent;
    self.keyboardToolbar.tintColor = [UIColor darkGrayColor];

    btnPrev = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:@selector(gotoPrevTextfield:)];
    btnNext = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:@selector(gotoNextTextfield:)];
    btnDone = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneTyping:)];

    [self.keyboardToolbar addSubview:(UIView*)btnPrev];
    [self.keyboardToolbar addSubview:(UIView*)btnNext];
    [self.keyboardToolbar addSubview:(UIView*)btnDone];

    [self.firstNameTextField setInputAccessoryView:self.keyboardToolbar];
    [self.lastNameTextField setInputAccessoryView:self.keyboardToolbar];
    [self.cityTextField setInputAccessoryView:self.keyboardToolbar];
}

-(void)textFieldDidBeginEditing:(UITextField*)textField
{
    self.txtActiveField = textField;
}
@end

当我启动应用程序时，我得到：

012-01-21 09:31:19.798 KeyboardToolbar[14772:f803] -[UIBarButtonItem superview]: unrecognized selector sent to instance 0x6b19350
2012-01-21 09:31:19.799 KeyboardToolbar[14772:f803] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIBarButtonItem superview]: unrecognized selector sent to instance 0x6b19350'
*** First throw call stack:
(0x13bc052 0x154dd0a 0x13bdced 0x1322f00 0x1322ce2 0x5042f 0x4a72b 0x3422 0x2a58 0xd964e 0x39a73 0x39ce2 0x39ea8 0x40d9a 0x11be6 0x128a6 0x21743 0x221f8 0x15aa9 0x12a6fa9 0x13901c5 0x12f5022 0x12f390a 0x12f2db4 0x12f2ccb 0x122a7 0x13a9b 0x2728 0x2685 0x1)
terminate called throwing an exception

我的假设是我没有正确分配其中一个元素。我还想知道是否需要在类中为按钮添加字段，或者是否可以将它们添加到工具栏中。我在标题中添加了一行，这样我就不必将所有方法都放在文件的开头。还不知道像在 C 中那样转发声明方法的语法。

Thanks.

Update:

所以我对 createInputAccessoryView 做了一些更改。我现在使用 addItems 来添加按钮。我将按钮变量设置为本地变量（但与以前一样时遇到了相同的问题）。好消息是应用程序不再崩溃，坏消息是工具栏显示，但没有任何按钮。不知道我还需要做什么才能让按钮实际显示。我见过的所有例子都是相似的。

-(void)createInputAccessoryView
{
    self.keyboardToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 44)];
    self.keyboardToolbar.barStyle = UIBarStyleBlackTranslucent;
    self.keyboardToolbar.tintColor = [UIColor darkGrayColor];

    UIBarButtonItem* previousButton = [[UIBarButtonItem alloc] initWithTitle:@"Previous" style:UIBarButtonItemStyleBordered target:self action:@selector(gotoPrevTextfield)];
    UIBarButtonItem* nextButton = [[UIBarButtonItem alloc] initWithTitle:@"Next" style:UIBarButtonItemStyleBordered target:self action:@selector(gotoNextTextfield)];
    UIBarButtonItem* flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    UIBarButtonItem* doneButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneTyping:)];

    [keyboardToolbar setItems:[NSArray arrayWithObjects: previousButton, nextButton, flexSpace, doneButton, nil] animated:NO];

    [self.firstNameTextField setInputAccessoryView:self.keyboardToolbar];
    [self.lastNameTextField setInputAccessoryView:self.keyboardToolbar];
    [self.cityTextField setInputAccessoryView:self.keyboardToolbar];
}

UIBarButtonItem不是一个UIView子类，因此您不能将其添加为子视图UIToolbar。相反，使用– setItems:animated:工具栏上的方法来添加这些按钮。