【问题】
折腾Picker View的过程中，遇到变量使用出错：
【解决过程】
1.后来经过折腾，发现是 property和instance value之间的区别没有搞清楚，
解决办法是：
(1)要么去interface中定义实例变量：
1 2 3 4 5 6 7 8 9 10 | //// AddSightingViewController.h// BirdWatching//@interface AddSightingViewController : UITableViewController <UITextFieldDelegate, UIPickerViewDataSource, UIPickerViewDelegate>{ //NSArray *birdNameList;}@property (strong, nonatomic) NSArray *birdNameList; |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | //// AddSightingViewController.m// BirdWatching//@implementation AddSightingViewController//@synthesize birdNameList = _birdNameList;- (void)viewDidLoad{ [super viewDidLoad]; self.birdNameList = [[NSArray alloc] initWithObjects:@"Ostrich", @"Penguin", @"HummingBird", nil];} |
(2)要么去使用property属性变量：
1 2 3 4 5 6 7 8 9 10 | //// AddSightingViewController.h// BirdWatching//@interface AddSightingViewController : UITableViewController <UITextFieldDelegate, UIPickerViewDataSource, UIPickerViewDelegate>{ NSArray *birdNameList;}//@property (strong, nonatomic) NSArray *birdNameList; |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | //// AddSightingViewController.m// BirdWatching//@implementation AddSightingViewController//@synthesize birdNameList = _birdNameList;- (void)viewDidLoad{ [super viewDidLoad]; birdNameList = [[NSArray alloc] initWithObjects:@"Ostrich", @"Penguin", @"HummingBird", nil];} |
这样，至少就解决了编译的错误问题了。
而关于两者之间的区别，详情参考：
【整理】Object-C中属性（property）与实例变量（instance variable）之间的区别
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