可以以编程方式提供iOS预测键盘上下文/源文本？

#import "SuggestionView.h"

#define kScreenWidth [UIScreen mainScreen].bounds.size.width

@implementation SuggestionView {
    NSMutableOrderedSet *_suggestions;
    NSMutableArray *_suggestionButtons;
}

- (instancetype)init {
    self = [self initWithFrame:CGRectMake(0.0f, 0.0f, kScreenWidth, 36.0f)];

    if (self) {

    }

    return self;
}

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame inputViewStyle:UIInputViewStyleKeyboard];

    if (self) {
        _suggestiOns= [[NSMutableOrderedSet alloc] initWithCapacity:3];
        self.maxSuggestiOnCount= 3;
        _suggestiOnButtons= [[NSMutableArray alloc] init];
        self.backgroundColor = [UIColor colorWithWhite:0.0f alpha:0.04f];
    }

    return self;
}

#pragma mark - Modifying Suggestions

- (void)addSuggestion:(NSString *)suggestion {
    if (suggestion) {
        [_suggestions addObject:suggestion];
    }

    while (_suggestions.count > self.maxSuggestionCount) {
        [_suggestions removeObjectAtIndex:self.maxSuggestionCount];
    }
}

- (void)removeSuggestion:(NSString *)suggestion {
    [_suggestions removeObject:suggestion];
}

- (void)setSuggestions:(NSObject *)suggestions {
    if ([suggestions respondsToSelector:@selector(countByEnumeratingWithState:objects:count:)]) {
        [_suggestions removeAllObjects];

        for (NSString *suggestion in (NSArray *)suggestions) {
            if (_suggestions.count  0) {
            UIView *whiteLine = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 0.5f, self.bounds.size.height)];
            whiteLine.backgroundColor = [UIColor whiteColor];
            [suggestionButton addSubview:whiteLine];
        }

        [_suggestionButtons addObject:suggestionButton];
    }
}

#pragma mark - Selecting a Suggestion

- (void)buttonTouched:(UIButton *)button {
    NSTimeInterval animatiOnDuration= 0.09f;
    [UIView animateWithDuration:animationDuration animations:^{
        [button setBackgroundColor:[UIColor whiteColor]];

        if ([self.delegate respondsToSelector:@selector(suggestionSelected:)]) {
            [self performSelector:@selector(suggestionSelected:) withObject:button.currentTitle afterDelay:animationDuration * 0.9f];
        }

        [button performSelector:@selector(setBackgroundColor:) withObject:[UIColor clearColor] afterDelay:animationDuration];
    }];
}

- (void)suggestionSelected:(NSString *)suggestion {
    if ([self.delegate respondsToSelector:@selector(suggestionSelected:)]) {
        [self.delegate suggestionSelected:suggestion];
    }
}

@end

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    if ([textField isEqual:self.messageTextField]) {
        if (self.suggestionView.suggestions.count > 0 && textField.text.length == 0) {
            textField.inputAccessoryView = self.suggestionView;
            textField.autocorrectiOnType= UITextAutocorrectionTypeNo;
            [textField reloadInputViews];
        }
    }

    return YES;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if ([textField isEqual:self.messageTextField]) {
        if (string.length > 0) {
            [self removeSuggestionView];
        }
    }

    return YES;
}


- (void)removeSuggestionView {
    self.messageTextField.inputAccessoryView = nil;
    [self.messageTextField setInputAccessoryView:nil];
    self.messageTextField.autocorrectiOnType= UITextAutocorrectionTypeYes;
    [self.messageTextField reloadInputViews];

    [self.messageTextField performSelector:@selector(resignFirstResponder) withObject:self afterDelay:0.0f];
    [self.messageTextField performSelector:@selector(becomeFirstResponder) withObject:self afterDelay:0.0f];
}

- (void)suggestionSelected:(NSString *)suggestion {
    [self.messageTextField setText:[NSString stringWithFormat:@"%@%@ ", self.messageTextField.text, suggestion]];
    [self removeSuggestionView];
}