采用UIKeyInput协议实现蓝牙键盘的输入

Question

我有一个蓝牙脚踏开关，基本上就是一个无线键盘。一个踏板发送向上箭头键，另一个发送向下箭头键。我希望当其中一个踏板被按下时，能够在我的iPad应用程序中执行我自己的代码。踏板的制造商告诉我应该创建一个UITextField，并在包含的UIView中采用UIKeyInput协议，并使用beginningOfDocument和endOfDocument方法来执行我的代码。我这样做了，但无论我做什么，都不会调用任何UIKeyInput或UITextInput方法。有没有人可以给我介绍一下，或者给我一个类似的教程？有没有更简单的方法来做这件事？

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

下面是我的.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

看看我想出的响应脚踏板箭头键的解决方案：

How can I respond to external keyboard arrow keys?

Answer 2

在iOS7中，这很容易。在以前的版本中--非官方版本。可以从App Store中删除。

-(NSArray * ) keyCommands {
    if ([[[UIDevice currentDevice] systemVersion] intValue] <7) return nil;
    UIKeyCommand *upArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputUpArrow modifierFlags: 0 action: @selector(upArrow:)];
    UIKeyCommand *downArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputDownArrow modifierFlags: 0 action: @selector(downArrow:)];
    UIKeyCommand *leftArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputLeftArrow modifierFlags: 0 action: @selector(leftArrow:)];
    UIKeyCommand *rightArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputRightArrow modifierFlags: 0 action: @selector(rightArrow:)];
    UIKeyCommand *escapeCom = [UIKeyCommand keyCommandWithInput:UIKeyInputEscape modifierFlags:0 action:@selector(escapeChar:)];
    return [[NSArray alloc] initWithObjects: upArrow, downArrow, leftArrow, rightArrow, escapeCom, nil];
}

这对我很有效，希望对你有用。添加版本检查，以避免在非iOS7设备中使用。