采用UIKeyInput协议从蓝牙键盘获取输入

Question

我有一个蓝牙脚踏开关,基本上是一个无线键盘.一个踏板发送向上箭头键,另一个发送向下箭头键.我希望能够在我的iPad应用程序中按下其中一个踏板时执行我自己的代码.踏板的制造者告诉我应该创建一个UITextField,并UIKeyInput在包含UIView中采用协议并使用beginningOfDocument和endOfDocument方法来执行我的代码.我这样做了,但不管我做什么,都不会调用UIKeyInput或UITextInput方法.任何人都可以引导我完成这个,或者指导我学习与此相似的教程吗？有更简单的方法吗？

谢谢你的帮助.

这是我的.h:

#import <UIKit/UIKit.h>

@interface Pedal_ProtocolViewController : UIViewController <UIKeyInput, UITextInput>{
UITextField *myTextField;
}
@property (nonatomic, retain) IBOutlet UITextField *myTextField;
@end

这是我的.m:

#import "Pedal_ProtocolViewController.h"

@implementation Pedal_ProtocolViewController

@synthesize myTextField;

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

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
[super viewDidLoad];
[myTextField canBecomeFirstResponder];
[myTextField becomeFirstResponder];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return YES;
}

#pragma mark -
#pragma mark UIKeyInput Protocol Methods

- (BOOL)hasText {
    return NO;
}

- (void)insertText:(NSString *)theText {
}

- (void)deleteBackward {
}

- (BOOL)canBecomeFirstResponder {
    return YES; 
}

#pragma mark -
#pragma mark UITextInput Protocol Methods

- (NSString *)textInRange:(UITextRange *)range {
    return @"";
}
- (void)replaceRange:(UITextRange *)range withText:(NSString *)text {
}
- (void) setSelectedTextRange: (UITextRange *) range {
}
- (UITextRange *) markedTextRange {
    return nil;
}
- (NSDictionary *) markedTextStyle {
    return nil;
}
- (void) setMarkedTextStyle: (NSDictionary *) style {
}
- (void)setMarkedText:(NSString *)markedText selectedRange:(NSRange)selectedRange {
}
- (void) unmarkText {
}
- (UITextPosition *) endOfDocument {
    //DOWN KEY

    NSLog(@"Down");
    return nil;
}
- (UITextPosition *) beginningOfDocument {
    //UP KEY

    NSLog(@"UP");
    return nil;
}
- (UITextRange *)textRangeFromPosition:(UITextPosition *)fromPosition toPosition:(UITextPosition *)toPosition{
    return nil;
}
- (UITextPosition *)positionFromPosition:(UITextPosition *)position offset:(NSInteger)offset{
    return nil;
}
- (UITextPosition *)positionFromPosition:(UITextPosition *)position inDirection:(UITextLayoutDirection)direction offset:(NSInteger)offset {
    return nil;
}
- (NSComparisonResult) comparePosition: (UITextPosition *)position toPosition: (UITextPosition *)other {
    return NSOrderedSame;
}
- (NSInteger) offsetFromPosition: (UITextPosition *)from toPosition: (UITextPosition *)toPosition {
    return 0;
}
- (void) setInputDelegate: (id <UITextInputDelegate>) delegate {
}
- (id <UITextInputDelegate>) inputDelegate {
    return nil;
}
- (id <UITextInputTokenizer>) tokenizer {
    return nil;
}
- (UITextPosition *)positionWithinRange:(UITextRange *)range farthestInDirection:(UITextLayoutDirection)direction {
    return nil;
}
- (UITextRange *) characterRangeByExtendingPosition: (UITextPosition *) position inDirection: (UITextLayoutDirection) direction {
    return nil;
}
- (UITextWritingDirection) baseWritingDirectionForPosition: (UITextPosition *)position inDirection: (UITextStorageDirection)direction {
    return 0;
}
- (void) setBaseWritingDirection: (UITextWritingDirection)writingDirection forRange:(UITextRange *)range {
}
- (CGRect) firstRectForRange: (UITextRange *) range {
    return CGRectZero;
}
- (CGRect) caretRectForPosition: (UITextPosition *) position  {
    return CGRectZero;
}
- (UITextPosition *) closestPositionToPoint: (CGPoint)point {
    return nil;
}
- (UITextPosition *) closestPositionToPoint: (CGPoint)point withinRange: (UITextRange *) range {
    return nil;
}
- (UITextRange *) characterRangeAtPoint: (CGPoint)point {
    return nil;
}
- (UITextRange *) selectedTextRange {
    return [[UITextRange alloc]init];
}

@end

Answer 1

你已经采用UIKeyInput了UIViewController.请注意您输入的继承定义:

@interface Pedal_ProtocolViewController : UIViewController <UIKeyInput, UITextInput>{

你在这里说过"这是一个实现UIKeyInput和的视图控制器UITextInput." 这两个协议适用于UIResponder子类,如UIView子类或子类UIView.UIViewController是不是其中一类,可能不处理文本输入的最佳类.

View控制器管理视图.他们不是自己的观点.

您可以(而不是文本输入协议)只使用隐藏的文本字段(例如您已有的字段).只需创建一个子类,NSObject 它实现文本字段的委托,并将其指定为文本字段的委托.然后,在-viewDidAppear:,调用-becomeFirstResponder文本字段以关注该字段.您可以使用一些黑客来隐藏键盘.

这种方法通常用于游戏和游戏支持库中以显示软件键盘.它甚至适用于iOS 3.1.3及更早版本(考虑到您正在为iPad开发,这对您来说不是问题).

如果您将保留该设计(在视图控制器中处理输入),则可能需要这样做并使其工作.

-(BOOL)canBecomeFirstResponder
{
    return YES;
}

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    [self becomeFirstResponder];
}

请考虑使用UITextField和委托来处理输入,或者UIKeyInput在子类中实现上述两个函数和协议UIView.

另请注意,您无需遵守UITextInput以获得按键; UIKeyInput足够.

附加说明:如果你决定子类UIView(这与我使用的隐藏UITextField,是我做的;我没有尝试子类化UIViewController来获取键盘输入),你会想要添加-becomeFirstResponder到-awakeFromNib:

-(void)awakeFromNib
{
    [super awakeFromNib];
    [self becomeFirstResponder];
}

那就是你从笔尖加载UIViewController(以及因此UIView).不这样做？尝试添加-initWithFrame::

-(id)initWithFrame:(CGFrame)frame
{
    self = [super initWithFrame:frame];
    if(!self)
        return nil;

    [self becomeFirstResponder];
    return self;
}

或者,在UIViewController中viewDidLoad:

    // ...
    [self.view becomeFirstResponder];
    // ...

显然有很多方法可以做到这一点.;)