点击下一步按钮清除触摸uiimageview

Question

如何删除填充的颜色？

我的代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    alphabetsStoreArray = [[NSMutableArray alloc]initWithObjects:
        @"write a.png", @"write b.png", @"write c.png",
        @"write d.png", @"write e.png", @"write f.png", 
        @"write g.png", @"write h.png", @"write i.png",
        @"write j.png", @"write k.png", @"write l.png",
        @"write m.png", @"write n.png", @"write o.png",
        @"write p.png", @"write q.png", @"write r.png",
        @"write s.png", @"write t.png", @"write u.png",
        @"write v.png", @"write w.png", @"write x.png",
        @"write y.png", @"write z.png", nil];

    _homePopupView.hidden=true;

    [self names];
}

-(void)names{
     _voice = @"en-US";
    _speed = .25f;
    if(count>= alphabetsStoreArray.count)
    {
        printf("%d", count);
        NSLog(@"finished");
        [_alphabetChangeImageView removeFromSuperview];
        [_alphabetBackgroundImageView removeFromSuperview];
    }

    else if(count<alphabetsStoreArray.count||count<-1)
    {
        items = [[alphabetsStoreArray objectAtIndex:count] componentsSeparatedByString:@"."];

        NSString *tempString = [items objectAtIndex:0];
        NSArray *tempArray = [tempString componentsSeparatedByString:@" "];
        speechString1 = [tempArray objectAtIndex:1];

        if ([_synthesizer isPaused]) {
            [_synthesizer continueSpeaking];
        }

        else{
            [self speakText:speechString1];
              [self textToSpeechAction:alphabetsStoreArray :count :_alphabetBackgroundImageView  :_alphabetChangeImageView :isMicPresent];


        }
    }
}

-(void)textToSpeechAction:(NSMutableArray *)imageStoreArray :(int)counter :(UIImageView *)imageChangeImageView :(UIImageView *)spekerOrMic :(BOOL)isMicPresent
{
    _alphabetChangeImageView.image = [UIImage imageNamed:[imageStoreArray objectAtIndex:counter]];
}

- (void)speakText:(NSString*)text{
    if(_synthesizer == nil)
        _synthesizer = [[AVSpeechSynthesizer alloc] init];
    _synthesizer.delegate = self;

    AVSpeechUtterance *utterence = [[AVSpeechUtterance alloc] initWithString:text];
    utterence.rate = _speed;

    AVSpeechSynthesisVoice *voice = [AVSpeechSynthesisVoice voiceWithLanguage:_voice];
    [utterence setVoice:voice];

    [_synthesizer speakUtterance:utterence];
}

- (void) touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event

{
    // Initialize a new path for the user gesture
    UITouch *touch = [[event allTouches] anyObject];

    CGPoint location = [touch locationInView:_alphabetBackgroundImageView];

    if((location.x > 50 && location.x < _alphabetBackgroundImageView.frame.size.width-50) && (location.y > 50 && location.y < _alphabetBackgroundImageView.frame.size.height-50))

    {
       lineImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
        lineImageView.center = location;
        lineImageView.backgroundColor = selectedColor;
        [_alphabetBackgroundImageView addSubview:lineImageView];
    }
}

- (void) touchesMoved:(NSSet *) touches withEvent:(UIEvent *) event

{
    // Add new points to the path
    UITouch *touch = [[event allTouches] anyObject];

    CGPoint location = [touch locationInView:_alphabetBackgroundImageView];

    if((location.x > 50 && location.x <_alphabetBackgroundImageView.frame.size.width-50) && (location.y > 50 && location.y < _alphabetBackgroundImageView.frame.size.height-50))

    {
       lineImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];

        lineImageView.center = location;
        lineImageView.backgroundColor = selectedColor;
        [_alphabetBackgroundImageView addSubview:lineImageView];
    }
}

- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSSet* touchesForTargetView = [event touchesForView:self.alphabetBackgroundImageView];

    if (touchesForTargetView.allObjects.count != 0) {
        NSLog(@"yes");
        // touch was at target view
    }
    else {
        NSLog(@"no");
        // touch  was somewhere else
    }
}

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didStartSpeechUtterance:(AVSpeechUtterance *)utterance{
    [self buttonoperation];
    _next.enabled = YES;
}

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didCancelSpeechUtterance:(AVSpeechUtterance *)utterance{

    // Enable/Disable buttons accordingly
    [self buttonoperation];

    _retry.enabled = NO;
    count +=1;
    [self names];
}

- (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer willSpeakRangeOfSpeechString:(NSRange)characterRange utterance:(AVSpeechUtterance *)utterance{

    // Get the text
    NSString *text = [utterance speechString];

    // apply attribute
    NSMutableAttributedString * all = [[NSMutableAttributedString alloc] initWithString:text];
    [all addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:characterRange];

    // set the attributed text to textView
    [_tvTextToSpeak setAttributedText:all];
}

- (IBAction)nextAction:(id)sender {
    if ([_synthesizer isSpeaking]) {
        [_synthesizer stopSpeakingAtBoundary:AVSpeechBoundaryImmediate];
        [self buttonoperation];
        _next.enabled = NO;
        [_tvTextToSpeak setText:speechString1];
    }
    count++;
    [self names];
}

这里我有两个imageview 1.aplhabetbackground 2.alphabetchangingbackground。

因此，根据我的代码，当下一个按钮点击来自字母存储阵列的第二个数据时，它的图像将显示在imageview中。所以点击下一个按钮就会显示下一个图像。

这里我在字母表背景中使用了触摸事件。因此，当显示图像时，我可以在屏幕上触摸并填充所选颜色。

但是我需要在点击下一个按钮时填充颜色应该从中删除。怎么做