【发布时间】:2011-06-07 17:08:36
【问题描述】:
我正在尝试使用 NSMutableArray 将按钮添加到滚动视图。该代码在我用作参考的 twitter 示例中运行良好,但由于某种原因,它在这种情况下不起作用。在 twitter 搜索案例中,代码在主类中实现。在这种情况下,我在反面视图中实现它。任何人都可以帮助我,因为我对Objective c有点陌生。 提前致谢。
这里是初始化 NSMutableArray 按钮的 init
- (id)init
{
self = [super init]; // initialize the superclass members
if (self != nil) // if the superclass initialized properly
{
// creates list of valid directories for saving a file
NSArray *paths = NSSearchPathForDirectoriesInDomains(
NSDocumentDirectory, NSUserDomainMask, YES);
// get the first directory
NSString *dir = [paths objectAtIndex:0];
// concatenate the file name "tagsIndex.plist" to the path
filePath = [[NSString alloc] initWithString:
[dir stringByAppendingPathComponent:@"tagsIndex.plist"]];
NSFileManager *fileManager = [NSFileManager defaultManager];
// if the file does not exist, create an empty NSMutableDictionary;
// otherwise, initialize an NSDictionary with the file's contents
if ([fileManager fileExistsAtPath:filePath] == NO)
{
tags = [[NSMutableDictionary alloc] init];
} // end if
else
{
tags = [[NSMutableDictionary alloc]
initWithContentsOfFile:filePath];
} // end else
buttons = [[NSMutableArray alloc] init]; // create array
infoButtons = [[NSMutableArray alloc] init]; // create array
}
return self; // if self == nil, object not initialized properly
} // end method init
这里我们有将对象添加到按钮数组但它保持为空的方法。
- (void)addNewButtonWithTitle:(NSString *)title
{
// create a new button
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
// give the button the title of the tag
[button setTitle:title forState:UIControlStateNormal];
// tell the button to call buttonTouched: when it is touched
[button addTarget:self action:@selector(buttonTouched:)
forControlEvents:UIControlEventTouchUpInside];
[buttons addObject:button]; // add the UIButton to the end of the array
//This Doesn't add it stays 0;
// sort the NSMutableArray by the UIButton's titles
[buttons sortUsingSelector:@selector(compareButtonTitles:)];
[self refreshList]; // refresh the list of favorite search Buttons
// Adjust the content size of the view to include the new button. The
// view scrolls only when the content size is greater than its frame.
CGSize contentSize = CGSizeMake(scrollView.frame.size.width,
buttons.count * (BUTTON_HEIGHT + BUTTON_SPACING) + BUTTON_SPACING);
[scrollView setContentSize:contentSize];
}
这是我释放按钮数组的dealloc。
- (void)dealloc {
[buttons release];
[super dealloc];
}
我不知道错误在哪里。
这是应该添加新按钮的代码。
- (IBAction)addTag:sender
{
// make the keyboard disappear
[ItemTitleField resignFirstResponder];
[QuantityField resignFirstResponder];
NSString *key = ItemTitleField.text; // get the text in tagField
NSString *value = QuantityField.text; // get the text in queryField
// test if either field is empty
if (value.length == 0 || key.length == 0)
return; // exit from the method
if ([tags valueForKey:key] == nil) // test if the tag already exists
[self addNewButtonWithTitle:key]; // if not, add a new button
[tags setValue:value forKey:key]; // add a new entry in tags
ItemTitleField.text = nil; // clear tagField of text
QuantityField.text = nil; // clear queryField of text
[tags writeToFile:filePath atomically:NO]; //save the data
} // end method addTag:
【问题讨论】:
-
你确定,当你打电话给
[buttons addObject:button];,buttons不是零?你怎么知道这不加按钮? -
在您的代码中,我看不到您将按钮添加到视图的位置。你能提供这个吗?
-
我正在调试代码,它告诉我按钮有 0 个对象
-
将
count发送到nil对象将返回0。您能否验证它不是nil?
标签: objective-c