Question

我有一个tableView显示一些控件。在UIButton中正确的ans喜欢选项。我想在正确的ans中更改按钮背景图像和在click事件中错误的ans。我可以这样做吗？可以任何一个给我一个主意？我正在尝试将背景图像更改为：

 [cell.ansBtn2 setImage:[UIImage imageNamed:@"option_red.png"]  forState:UIControlStateSelected];

我将背景设置为：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

     static NSString *CellIdentifier = @"BeginingCell";

     cell=(BeginingCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];


    if (cell == nil) {

               NSArray *topLevelObjects=[[NSBundle mainBundle] loadNibNamed:@"BeginingCell" owner:self options:nil ];

        for(id CurrentObject in topLevelObjects)
        {
            if ([CurrentObject isKindOfClass:[BeginingCell class]]) {

                cell=(BeginingCell *) CurrentObject;
                cell.selectionStyle = UITableViewCellSelectionStyleNone;


                break;
            }
        }

    }


    if(indexPath.row==0)
    {


                imageURL=[dictionary objectForKey:@"questionImage"];

        NSURL *url = [NSURL URLWithString:imageURL];
        NSData *data = [NSData dataWithContentsOfURL:(NSURL *)url];
        UIImage *img = [[UIImage alloc]  initWithData:data];



        cell.lblScoreCurrent.text=[NSString stringWithFormat:@"%d", reloader];

        cell.lblScore.text=@"/30";
        cell.myImageView.image = img;
        cell.SectionTitle.text=[dictionary objectForKey:@"question"];




        cell.ansBtn1.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
        cell.ansBtn2.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
        cell.ansBtn3.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
        cell.ansBtn4.titleLabel.lineBreakMode = UILineBreakModeWordWrap;



        cell.ansBtn1.titleLabel.textAlignment = UITextAlignmentCenter;
        cell.ansBtn2.titleLabel.textAlignment = UITextAlignmentCenter;
        cell.ansBtn3.titleLabel.textAlignment = UITextAlignmentCenter;
        cell.ansBtn4.titleLabel.textAlignment = UITextAlignmentCenter;


        [cell.ansBtn1 setTitle:[dictionary objectForKey:@"option1"] forState:UIControlStateNormal];
        [cell.ansBtn2 setTitle:[dictionary objectForKey:@"option2"] forState:UIControlStateNormal];
        [cell.ansBtn3 setTitle:[dictionary objectForKey:@"option3"] forState:UIControlStateNormal];
        [cell.ansBtn4 setTitle:[dictionary objectForKey:@"option4"] forState:UIControlStateNormal];


        [cell.ansBtn1 addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
        [cell.ansBtn2 addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
        [cell.ansBtn3 addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
        [cell.ansBtn4 addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];



    }


    return cell;

}

这是点击事件：

      -(void) btnAction:(id) sender {

NSString *str =((UIButton*)sender).titleLabel.text;

NSLog(@"%@",str);
NSLog(@"%@",[dictionary objectForKey:@"option3"]);

correctAns=[dictionary objectForKey:@"answer"];

if(str==[dictionary objectForKey:@"option1"])
{
    selectedAns=@"1";

    if ([selectedAns compare:correctAns]==NSOrderedSame) 
    {

    [cell.ansBtn1 setBackgroundImage:[UIImage imageNamed:@"option_green.png"] forState:UIControlStateHighlighted];
     NSLog(@"this is correct");

     countCorrect++;
     cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];


    }

    else 
    {

        [cell.ansBtn1 setBackgroundImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateHighlighted];
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }

}

else if(str==[dictionary objectForKey:@"option2"])
{
    selectedAns=@"2";
    if ([selectedAns compare:correctAns]==NSOrderedSame) 
    {
        [cell.ansBtn2 setBackgroundImage:[UIImage imageNamed:@"option_green.png"] forState:UIControlStateHighlighted];
        NSLog(@"this is correct");
        countCorrect++;
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }

    else 
    {
        [cell.ansBtn2 setBackgroundImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateHighlighted];
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }
}


else if(str==[dictionary objectForKey:@"option3"])
{

    selectedAns=@"3";
    NSLog(@"selected ans is %@",selectedAns);
    NSLog(@"correct ans is %@",correctAns);

    if ([selectedAns compare:correctAns]==NSOrderedSame) 
    {
        [cell.ansBtn3 setBackgroundImage:[UIImage imageNamed:@"option_green.png"] forState:UIControlStateHighlighted];
        NSLog(@"this is correct");

        countCorrect++;
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }

    else 
    {
        [cell.ansBtn3 setBackgroundImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateHighlighted];
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }

}

else if(str==[dictionary objectForKey:@"option4"])
{

    selectedAns=@"4";
    NSLog(@"selected ans is %@",selectedAns);
    NSLog(@"correct ans is %@",correctAns);

    if ([selectedAns compare:correctAns]==NSOrderedSame) 
    {

        [cell.ansBtn4 setBackgroundImage:[UIImage imageNamed:@"option_green.png"] forState:UIControlStateHighlighted];

        countCorrect++;
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];

    }

    else 
    {
        [cell.ansBtn4 setBackgroundImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateHighlighted];
        cell.lblRating.text=[NSString stringWithFormat:@"%i", countCorrect];            

    }

}


else {
    NSLog(@"ERROR");
}


reloader++;

if (reloader>=[QuestionMutableArray count]) {



    NSString *str=[self GetSkill];
    NSString *totalTime=[NSString stringWithFormat:@"%i . %i minutes",7-timeMin,60-timeSecond];
    NSString *str2=[NSString stringWithFormat:@"Game Over :\n Knowlwdge Level : %@  \n Total Correct Answer :%i \n Total Time : %@ \n Total Question Answered : %i \n",str,countCorrect,totalTime,reloader];

    appAlert=[[UIAlertView alloc]initWithTitle:@"Game Over :\n" message:str2 
                                               delegate:self cancelButtonTitle:@"Exit" otherButtonTitles:nil];
    [appAlert addButtonWithTitle:@"PlayAgain"];



    UIImage *alertBoxImage = [UIImage imageNamed:@"first_look.jpg"];

    UIImageView *_backgroundImageView = [[UIImageView alloc] initWithImage:alertBoxImage];

    _backgroundImageView.frame = CGRectMake(0, 0, 282, 220);

    _backgroundImageView.contentMode = UIViewContentModeScaleToFill;

    [appAlert addSubview:_backgroundImageView];

    [appAlert sendSubviewToBack:_backgroundImageView]; 


    [appAlert show];        
    [dictionary release];
    [QuestionMutableArray release];
    countCorrect=0;


}
else {

    dictionary=[QuestionMutableArray objectAtIndex:reloader];
    [self.tableView reloadData];
}

}

问题是当我第一次点击按钮时背景没有改变。但是在下一次点击中我根据改变逻辑设置得到了改变（我的意思是绿色/红色改变）......应该怎么做我在这种情况下做。解决方案是什么？

Answer 1

更多编辑：
不要使用==检查字符串是否相等，而是使用isEqualToString：或compare：function

http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html

你可以做到

if([string1 compare:string2] == NSOrderedSame)
{
    //Do something...
}

因为==将检查内存位置中的2个指针地址而不是那些指针的内容。

OLD

您可以使用

http://developer.apple.com/library/ios/#documentation/uikit/reference/UIButton_Class/UIButton/UIButton.html#//apple_ref/occ/instm/UIButton/setBackgroundImage:forState：

或

http://developer.apple.com/library/ios/#documentation/uikit/reference/UIButton_Class/UIButton/UIButton.html#//apple_ref/occ/instm/UIButton/setImage:forState：

如果您将ans显示为按钮的标题标签，则必须使用setBackgroundImage:forState:

修改
而不是

[cell.ansBtn2 setImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateSelected];

你应该使用

[cell.ansBtn2 setBackgroundImage:[UIImage imageNamed:@"option_red.png"] forState:UIControlStateSelected];

因为您还必须将您的ans显示为该按钮的标题标签。

Answer 2

在UI按钮中添加目标方法。定义它 - （IBAction）btnClick：（id）sender。然后在此方法中从发送者对象创建按钮，因此每当我们单击按钮时，我们将使用按钮的setBackgroundImage方法获取发送者对象并更改其背景图像。这可能对你有所帮助。

UIButton背景图像单击更改

2 个答案: