我正在尝试创建一个随机显示按钮上的字母的程序.我希望能够单击按钮(开始),程序将生成一个随机字母作为按钮的标题(letter1).
每次运行此程序时,它立即崩溃:
#import "ViewController.h" @interface ViewController () @end @implementation ViewController -(IBAction)start:(id)sender{ int randomNumber = rand() % 25; switch (randomNumber){ case 0: [letter1 setTitle:@"A" forState:UIControlStateNormal]; break; case 1: [letter1 setTitle:@"B" forState:UIControlStateNormal]; break; case 2: [letter1 setTitle:@"C" forState:UIControlStateNormal]; break; case 3: [letter1 setTitle:@"D" forState:UIControlStateNormal]; break; case 4: [letter1 setTitle:@"E" forState:UIControlStateNormal]; break; case 5: [letter1 setTitle:@"F" forState:UIControlStateNormal]; break; case 6: [letter1 setTitle:@"G" forState:UIControlStateNormal]; break; case 7: [letter1 setTitle:@"H" forState:UIControlStateNormal]; break; case 8: [letter1 setTitle:@"I" forState:UIControlStateNormal]; break; case 9: [letter1 setTitle:@"J" forState:UIControlStateNormal]; break; case 10: [letter1 setTitle:@"K" forState:UIControlStateNormal]; break; case 11: [letter1 setTitle:@"L" forState:UIControlStateNormal]; break; case 12: [letter1 setTitle:@"M" forState:UIControlStateNormal]; break; case 13: [letter1 setTitle:@"N" forState:UIControlStateNormal]; break; case 14: [letter1 setTitle:@"O" forState:UIControlStateNormal]; break; case 15: [letter1 setTitle:@"P" forState:UIControlStateNormal]; break; case 16: [letter1 setTitle:@"Q" forState:UIControlStateNormal]; break; case 17: [letter1 setTitle:@"R" forState:UIControlStateNormal]; break; case 18: [letter1 setTitle:@"S" forState:UIControlStateNormal]; break; case 19: [letter1 setTitle:@"T" forState:UIControlStateNormal]; break; case 20: [letter1 setTitle:@"U" forState:UIControlStateNormal]; break; case 21: [letter1 setTitle:@"V" forState:UIControlStateNormal]; break; case 22: [letter1 setTitle:@"W" forState:UIControlStateNormal]; break; case 23: [letter1 setTitle:@"X" forState:UIControlStateNormal]; break; case 24: [letter1 setTitle:@"Y" forState:UIControlStateNormal]; break; case 25: [letter1 setTitle:@"Z" forState:UIControlStateNormal]; break; default: [letter1 setTitle:@"&" forState:UIControlStateNormal]; break; } } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end
任何帮助,将不胜感激!!!!
您没有提供足够的信息来解释崩溃.但是你可以通过消除switch语句来大大缩短你的代码
-(IBAction)start:(id)sender { int randomValue = 'A' + arc4random_uniform(('Z' + 1) - 'A'); [letter1 setTitle: [NSString stringWithFormat:@"%c", randomValue]) forState:UIControlStateNormal]; }