Question

我正在制作一个小问答式应用程序，但我遇到了一些问题。

我使用arc4random（）从NSMutableArray中随机输出问题，然后用3个按钮填充视图，其中一个包含正确答案，另一个包含两个错误答案

我需要做的是随机化视图中3个按钮的X坐标（位置）这是我正在使用的代码，但它给我带来了问题，因为它无法正常工作和应用程序经常崩溃在调用动作时：

NSBundle *bundle02 = [NSBundle mainBundle];
NSString *textFilePath02 = [bundle02 pathForResource:@"possiblePositions" ofType:@"txt"];   
NSString *fileContents02 = [NSString stringWithContentsOfFile:textFilePath02 encoding:NSUTF8StringEncoding error:nil];
arrayPossiblePositions = [[NSMutableArray alloc] initWithArray:[fileContents02 componentsSeparatedByString:@"\n"]];

int length02 = [arrayPossiblePositions count];
int chosen02 = arc4random() % length02;
[arrayPossiblePositions removeObjectAtIndex:chosen02];
int chosen04 = arc4random() % length02;
[arrayPossiblePositions removeObjectAtIndex:chosen04];
int chosen05 = arc4random() % length02;

if ([questionString isEqualToString:@"question1"]) {

    buttonCorrect = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize = CGRectMake(chosen02, 80, 130, 130);
    buttonCorrect.frame = newSize;
    [buttonCorrect setImage:[UIImage imageNamed:@"kncpf.png"] forState:UIControlStateNormal];
    [buttonCorrect addTarget:self action:@selector(answerCorrect) forControlEvents:UIControlEventTouchUpInside];
    [main addSubview:buttonCorrect];

    buttonUncorrect01 = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize02 = CGRectMake(chosen04, 80, 130, 130);
    buttonUncorrect01.frame = newSize02;
    [buttonUncorrect01 setImage:[UIImage imageNamed:@"kncpf02.png"] forState:UIControlStateNormal];
    [buttonUncorrect01 addTarget:self action:@selector(answerUncorrect) forControlEvents:UIControlEventTouchUpInside];
    [main addSubview:buttonUncorrect01];

    buttonUncorrect02 = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize034578 = CGRectMake(chosen05, 80, 130, 130);
    buttonUncorrect02.frame = newSize034578;
    [buttonUncorrect02 setImage:[UIImage imageNamed:@"kncpf034578.png"] forState:UIControlStateNormal];
    [buttonUncorrect02 addTarget:self action:@selector(answerUncorrect) forControlEvents:UIControlEventTouchUpInside];
    [main addSubview:buttonUncorrect02];
}

你可以建议我做些不同的事情，因为我真的疯了吗？

提前感谢您的回答，大卫

Answer 1

我实际上需要做类似的事情，但不是移动图像，而是决定这样做：

创建三个要显示的按钮（预定位置）。
随机分配图像到每个按钮（通过随机化NSMutableArray和图像名称的NSStrings）。
不是分配@selector（answerCorrect）和@selector（answerUncorrect），而是分配@selector（checkIfCorrect :)
如此定义checkIfCorrect：

- （void）checkIfCorrect：（id）sender {UIImage * buttonImage = sender.image;

if（buttonImage == [UIImage   imageNamed：@“kncpf.png”]）{[self   answerCorrect]; } else {[self   answerIncorrect]; }

}

编辑包含我推荐的代码：

此外，您正在致电

int length02 = [arrayPossiblePositions count];
int chosen02 = arc4random() % length02;
[arrayPossiblePositions removeObjectAtIndex:chosen02];
int chosen04 = arc4random() % length02;
[arrayPossiblePositions removeObjectAtIndex:chosen04];
int chosen05 = arc4random() % length02;

请注意，length02保持不变，而arrayPossiblePositions的大小会发生变化。这可能是您的代码崩溃的第一个原因：您正试图从数组中删除索引，而不是数组计数！

我没有测试，但应该工作:(不要忘记定义上面提到的checkanswer（））

NSMutableArray *imagesArray = [NSMutableArray arrayWithObjects:@"image1.png", @"image2.png", @"image3.png", nil];

int count1 = [imagesArray count];
int index1 = arc4random() % count1;

button1 = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize = CGRectMake(30, 80, 130, 130);
    button1.frame = newSize;
    [button1 setImage:[UIImage imageNamed:[imagesArray objectAtIndex:index1]] forState:UIControlStateNormal];
    [button1 addTarget:self action:@selector(checkAnswer:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button1];

[imagesArray removeObjectAtIndex:index1];
int count2 = [imagesArray count];
int index2 = arc4random() % count2;

button2 = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize = CGRectMake(160, 80, 130, 130);
    button2.frame = newSize;
    [button2 setImage:[UIImage imageNamed:[imagesArray objectAtIndex:index2]] forState:UIControlStateNormal];
    [button2 addTarget:self action:@selector(checkAnswer:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button2];

[imagesArray removeObjectAtIndex:index2];
int count3 = [imagesArray count];
int index3 = arc4random() % count3;

button3 = [UIButton buttonWithType:UIButtonTypeCustom];
    CGRect newSize = CGRectMake(290, 80, 130, 130);
    button3.frame = newSize;
    [button3 setImage:[UIImage imageNamed:[imagesArray objectAtIndex:index3]] forState:UIControlStateNormal];
    [button3 addTarget:self action:@selector(checkAnswer:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button3];

Answer 2

我认为arc4random（）需要一个上限。不确定模数使用在这里是否正确或更可能是语义错误，不确定当您尝试执行类似操作时弧如何反应而不首先设置它的上限。我不确定，尝试用硬值代替你的长度02来看看你是否得到预期的行为，然后从那里向后工作。

随机化对象位置

2 个答案: