Question

我是iOS开发人员的新手，所以这可能很容易修复。我有一个自定义视图控制器，我正在采用协议来控制笔尖中的UIPickerView。一切正常，除非在iPad模拟器中，我将选择器滚动到列表中的第一项或列表中的最后一项并释放。它引发了以下错误：

线程1：编程接收信号：“EXC_BAD_ACCESS”

在我的main.m课程的这一行：

int retVal = UIApplicationMain（argc，argv，nil，nil）;

相关代码如下：

ViewController.h

@interface BirdColorViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource> {
IBOutlet UIPickerView *birdColorPicker;
NSArray *birdColors;
}

@property (nonatomic,retain) IBOutlet UIPickerView *birdColorPicker;

Viewcontroller.m

- (void)dealloc
{
[birdColorPicker release];
[super dealloc];
}

...

- (void)viewDidLoad
{
    [super viewDidLoad];
    birdColors = [NSArray arrayWithObjects:@"Blue",@"Yellow",@"Red",nil];

    birdColorPicker.delegate = self;
    birdColorPicker.dataSource = self;
}

...

#pragma mark - UIPickerViewDataSource methods

//(UIPickerView *)thePickerView

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component 
{
    return [birdColors count];
}

 #pragma mark - UIPickerViewDelegate methods

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component 
{
    return [birdColors objectAtIndex:row];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component 
{
    // Set value in prefs/model
}

Answer 1

尝试： birdColors = [[NSArray alloc] initWithObjects:@"Blue",@"Yellow",@"Red",nil]; 而不是birdColors = [NSArray arrayWithObjects:@"Blue",@"Yellow",@"Red",nil];

Answer 2

将birdColors设置为（非原子，保留）属性，就像使用pickerView一样。您的阵列未被保留，因此您正在访问僵尸内存。在可执行文件的属性/常规面板中设置NSZombieEnabled = YES。这将告诉你究竟正在访问什么。

滚动浏览列表的开头或结尾时，UIPickerView会崩溃应用程序

2 个答案: