iphone - 释放 Controller ，但保留空指针？

Question

我有一个变量 editForm，用作指向 View Controller 的指针。后来，当用户点击按钮关闭 View 时，我使用委托(delegate)方法来释放 editForm。

@implementation EditViewController

EditFormViewController *editForm;

[...]

 (void)openeditform:(NSString*)editId {
    editForm = [[EditFormViewController alloc] initWithNibName:@"EditFormView" bundle:nil editId:editId];

[...]

问题是， View 通常需要用新的石板重新创建。有没有办法释放 Controller ，同时保持空指针为将来的实例化做好准备？或者重新声明“EditFormViewController *editForm;”的方法来自方法内的语句？

编辑，这是完整的openeditform方法:

- (void)openeditform:(NSString*)editId {
    EditFormViewController* editFormController = [[EditFormViewController alloc] initWithNibName:@"EditFormView" bundle:nil editId:editId];
    [editFormController.view setFrame:CGRectMake(0, 0, 640, 460)];
    [self.view addSubview:editFormController.view];
    editFormController.delegate = self;
    [UIView beginAnimations:@"editform view open" context:nil];
    [UIView setAnimationDuration:0.5];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    [UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:self.view.superview cache:YES];
    [editFormController.view setFrame:CGRectMake(0, 0, 320, 460)];
    [UIView commitAnimations];
    self.editForm = editFormController;
    [editFormController release];
}

对于 Jerry Jones，以下是与删除 View 相关的内容。

EditFormViewController.m:

- (void) closeEditForm {
    [UIView beginAnimations:@"editform view close" context:nil];
    [UIView setAnimationDuration:0.5];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    [UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.view.superview cache:YES];
    //[UIView setAnimationDelegate:self];
    [self.view removeFromSuperview];
    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    [appDelegate reloadEditViewTable];
    [UIView commitAnimations];
    [delegate didDismissEditFormView];
}

还有委托(delegate)方法，由于我实现了 Estarriol 的建议，目前尚未用于任何用途，但该方法尚未完全实现我想要的功能:

- (void)didDismissEditFormView {
    NSLog(@"Fired delegate.");
    //[editForm release];
}

Answer 1

我认为你的EditFormViewController不应该是这里的变量，而是你的EditViewController的实例变量:

.h 文件:

@class EditFormViewController;
@interface EditViewController
{
....
EditFormViewController* editform;
...
}

...
@property (nonatomic, retain) EditFormViewController* editForm;
...

在你的 m 文件中:

@implementation EditViewController
...
-(void)openeditform:(NSString*)editId {
    EditFormViewController* editFormController = [[EditFormViewController alloc] initWithNibName:@"EditFormView" bundle:nil editId:editId];
self.editForm = editFormController;
[editFormController release];
...

这样，每次触发 opensitform 时都会重新创建它，并正确释放旧实例。