【发布时间】：2011-08-01 03:52:46
【问题描述】：
我想知道为什么由 UITextField 打开的 iPhone 键盘除了删除键和文本字段本身内的清除按钮之外没有输入任何内容。文本字段嵌入在带有此代码示例的 UIActionSheet 中：
// setup UITextField for the UIActionSheet
UITextField* textField = [[UITextField alloc] initWithFrame:CGRectMake(8.0, 34.0, 304.0, 30.0)];
NSString* startText = [[self.pathName lastPathComponent] stringByDeletingPathExtension];
textField.borderStyle = UITextBorderStyleRoundedRect;
textField.backgroundColor = [UIColor whiteColor];
textField.clearButtonMode = UITextFieldViewModeAlways;
textField.text = startText;
textField.delegate = self;
[textField setKeyboardType:UIKeyboardTypeAlphabet];
[textField setKeyboardAppearance:UIKeyboardAppearanceAlert];
// setup UIActionSheet
UIActionSheet* asheet = [[UIActionSheet alloc] initWithTitle: @"Please enter file name\n\n\n"
delegate: self
cancelButtonTitle: @"Cancel"
destructiveButtonTitle: nil
otherButtonTitles: @"OK", nil];
if ([currentView isKindOfClass:[UIToolbar class]])
[asheet showFromToolbar:(UIToolbar*)currentView];
else if ([currentView isKindOfClass:[UITabBar class]])
[asheet showFromTabBar:(UITabBar*)currentView];
else
[asheet showInView:currentView];
[asheet setFrame:CGRectMake(0.0, 60.0, 320.0, 380.0)];
[asheet insertSubview:textField atIndex:0];
[textField becomeFirstResponder];
// memory management
[textField release];
[asheet release];
我可以按 shift 键，但键不会变成小写，它们总是大写。好吧，我从来没有使用带有操作表的文本字段......我在这里做错了什么？操作表和文本字段的委托方法似乎根据需要存在。
编辑： 我也更改了操作表的视图关联和操作表的大小：
UIWindow* appWindow = [UIApplication sharedApplication].keyWindow;
[asheet showInView:appWindow];
[asheet setFrame:CGRectMake(0.0, 60.0, 320.0, 204.0)];
while (CGRectEqualToRect(asheet.bounds, CGRectZero))
;
// Add the text field to action sheet
[asheet addSubview:textField];
[textField release];
现在键盘没有被操作表重叠（或“underlapped”），操作表正确显示在状态栏和导航栏下方，键盘跟随在操作表下方并自下而上。
但只有 textFieldShouldBeginEditing 和 textFieldDidBeginEditing 会调用文本字段的委托方法，仅此而已。当我点击它时，Shift键会改变，擦除键起作用，所有其他键都会在点击时显示出来 - 但不要插入到文本字段中。那么，这到底是怎么回事？
解决方案： 感谢 SVD 向我指出似乎不可能将 UITextField 嵌入 UIActionSheet 的事实。因为我希望有一个方法可以返回带有操作表的文件名字符串（只是因为我更喜欢外观而不是添加了文本字段的 UIAlertView），所以我花了更多的工作，终于找到了一个可行的解决方案。我在这里分享它是因为我意识到你们中的很多人都在寻找类似的东西。
要使其发挥作用，需要考虑两个主要方面：
文本字段不能是操作表的子视图，至少在 处于可编辑状态的时刻
操作表不应与键盘重叠
好的，代码来了。模态解决方案与第二个运行循环一起使用，因此可以在不返回调用者的情况下处理文本字段和操作表的委托方法 - 我相信这可以分解为处理所有委托内容的传统方法你自己的班级。
ModalAction.h：
#import <UIKit/UIKit.h>
@interface ModalAction : NSObject
+ (NSString*)ask: (NSString*)question
withTextPrompt: (NSString*)prompt
textPreset: (NSString*)preset
dockToView: (UIView*)toView;
@end
ModalAction.m：
#import "ModalAction.h"
#define TEXT_FIELD_TAG 9999
#define ACTION_SHEET_TAG 8888
@interface ModalActionDelegate : NSObject <UIActionSheetDelegate, UITextFieldDelegate>
{
CFRunLoopRef currentLoop;
NSString* text;
NSUInteger index;
}
@property (assign) NSUInteger index;
@property (retain) NSString* text;
@end
@implementation ModalActionDelegate
@synthesize index;
@synthesize text;
-(id)initWithRunLoop: (CFRunLoopRef)runLoop
{
if (self = [super init])
currentLoop = runLoop;
return self;
}
// Activate keyboard
- (void)acceptInput: (UIActionSheet*)actionSheet
{
UITextField* textField = (UITextField*)[actionSheet viewWithTag:TEXT_FIELD_TAG];
UIWindow* appWindow = [UIApplication sharedApplication].keyWindow;
CGRect frame = textField.frame;
[appWindow insertSubview:textField aboveSubview:actionSheet];
frame.origin.y += 60.0; // move text field to same position as on action sheet
textField.frame = frame;
[textField becomeFirstResponder];
}
- (void)dealloc
{
self.text = nil;
[super dealloc];
}
#pragma mark -
#pragma mark === UIActionSheetDelegate ===
#pragma mark -
// User pressed button. Retrieve results
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
NSLog(@"actionSheet clickedButtonAtIndex:%d", buttonIndex);
UIWindow* appWindow = [UIApplication sharedApplication].keyWindow;
UITextField* textField = (UITextField*)[appWindow viewWithTag:TEXT_FIELD_TAG];
if (textField != nil)
self.text = textField.text;
self.index = buttonIndex;
CFRunLoopStop(currentLoop);
}
#pragma mark -
#pragma mark === UITextFieldDelegate ===
#pragma mark -
- (BOOL)textFieldShouldBeginEditing:(UITextField*)textField
{
NSLog(@"textFieldShouldBeginEditing");
return YES;
}
- (void)textFieldDidBeginEditing:(UITextField*)textField
{
NSLog(@"textFieldDidBeginEditing");
[textField becomeFirstResponder];
}
- (BOOL)textFieldShouldEndEditing:(UITextField*)textField
{
NSLog(@"textFieldShouldEndEditing");
return YES;
}
- (void)textFieldDidEndEditing:(UITextField*)textField
{
NSLog(@"textFieldDidEndEditing");
[textField resignFirstResponder];
}
- (BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString*)string
{
return YES;
}
- (BOOL)textFieldShouldClear:(UITextField*)textField
{
NSLog(@"textFieldShouldClearEditing");
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField*)textField
{
NSLog(@"textFieldShouldReturn (%@)", textField.text);
BOOL hasSomeText = ![textField.text isEqualToString:@""];
if (hasSomeText)
{
// send an OK to the action sheet
UIWindow* appWindow = [UIApplication sharedApplication].keyWindow;
UIActionSheet* actionSheet = (UIActionSheet*)[appWindow viewWithTag:ACTION_SHEET_TAG];
if (actionSheet != nil)
{
[actionSheet dismissWithClickedButtonIndex:0 animated:YES];
self.text = textField.text;
self.index = 0;
CFRunLoopStop(currentLoop);
[textField resignFirstResponder];
}
}
return hasSomeText;
}
@end
@implementation ModalAction
+ (NSString*)textQueryWith: (NSString*)question
prompt: (NSString*)prompt
textPreset: (NSString*)preset
button1: (NSString*)button1
button2: (NSString*)button2
forView: (UIView*)toView
{
// Create action sheet
CFRunLoopRef currentLoop = CFRunLoopGetCurrent();
ModalActionDelegate* madelegate = [[ModalActionDelegate alloc] initWithRunLoop:currentLoop];
NSString* sheetTitle = [question stringByAppendingString:@"\n\n\n"];
UIActionSheet* actionSheet = [[UIActionSheet alloc] initWithTitle: sheetTitle
delegate: madelegate
cancelButtonTitle: button1
destructiveButtonTitle: nil
otherButtonTitles: button2, nil];
actionSheet.tag = ACTION_SHEET_TAG;
// Build text field
UITextField* textField = [[UITextField alloc] initWithFrame:CGRectMake(8.0, 34.0, 304.0, 30.0)];
textField.borderStyle = UITextBorderStyleRoundedRect;
textField.tag = TEXT_FIELD_TAG;
textField.placeholder = prompt;
textField.text = preset;
textField.delegate = madelegate;
textField.clearButtonMode = UITextFieldViewModeWhileEditing;
textField.keyboardType = UIKeyboardTypeAlphabet;
textField.keyboardAppearance = UIKeyboardAppearanceAlert;
textField.autocapitalizationType = UITextAutocapitalizationTypeWords;
textField.autocorrectionType = UITextAutocorrectionTypeNo;
textField.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
textField.returnKeyType = UIReturnKeyDone;
// Show action sheet and wait for it to finish displaying
UIWindow* appWindow = [UIApplication sharedApplication].keyWindow;
[actionSheet showInView:appWindow];
[actionSheet setFrame:CGRectMake(0.0, 60.0, 320.0, 204.0)];
while (CGRectEqualToRect(actionSheet.bounds, CGRectZero))
;
// Add the text field to action sheet
[actionSheet addSubview:textField];
[textField release];
// Set the field to first responder and move it into place
[madelegate performSelector: @selector(acceptInput:) withObject: actionSheet];
// Start the run loop
CFRunLoopRun();
// Retrieve the user choices
NSUInteger index = madelegate.index;
NSString* answer = [[madelegate.text copy] autorelease];
if (index == 1)
answer = nil; // assumes cancel in position 1
[textField resignFirstResponder];
[actionSheet release];
textField.delegate = nil;
[textField removeFromSuperview];
[madelegate release];
return answer;
}
+ (NSString*)ask: (NSString*)question
withTextPrompt: (NSString*)prompt
textPreset: (NSString*)preset
dockToView: (UIView*)toView
{
return [ModalAction textQueryWith: question
prompt: prompt
textPreset: preset
button1: NSLocalizedString(@"AlertBtnCancel", @"")
button2: @"OK"
forView: toView];
}
@end
它在模拟器 iOS 4.2 和真实设备的 iOS 4.0.2 上运行 - 我希望它对其他人也有帮助。
【问题讨论】：
标签： iphone keyboard uitextfield uiactionsheet