我正在练习 TabViewcontroller 的工作原理。现在我有 UIViewcontroller 的 2 个子类。一个是 HypnosisViewController ，另一个是 TimeViewController。我想检查的是当 IOS 模拟器收到内存警告时-(void)viewDidLoad是如何工作的。我做到了
- 构建并运行应用程序
- 控制台说“HypnosisViewcontroller 加载了它的视图”。
- 切换了另一个选项卡（TimeViewController）
- 在控制台中看到了消息。它说“TabViewcontroller 加载了它的视图”
- IOS模拟器里有没有模拟器内存警告命令
- 控制台显示“HypnoTime 收到内存警告”。
- 切换回 HypnosisViewcontroller 以查看控制台是否显示“HypnosisViewcontroller 已加载其视图”。再次。
所以这里的问题是 HypnosisViewcontroller 没有被销毁并重新创建。（因为当我切换回 HypnosisViewcontroller 时我看不到日志消息。）但是我倾向于不在屏幕上的视图应该在内存警告期间被破坏。
我错过了什么？提前致谢！
HypnosisViewController.m:
#import "HypnosisViewController.h"
#import "HypnosisView.h"
@implementation HypnosisViewController
-(void)loadView
{
//Create a view
CGRect frame = [[UIScreen mainScreen] bounds];
HypnosisView *v = [[HypnosisView alloc] initWithFrame:frame];
// Set it as *the* view of this view controller
[self setView:v];
}
-(id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)bundle
{
self = [super initWithNibName:nil
bundle:nil];
if(self){
//Get the tab bar item
UITabBarItem *tbi = [self tabBarItem];
//Give it a label
[tbi setTitle:@"Hypnosis"];
//Create a UIImage from a file
//This will use Hypno@2x.png on retina display devices
UIImage *i = [UIImage imageNamed:@"Hypno.png"];
// Put that image on the tab bar item
[tbi setImage:i];
}
return self;
}
-(void)viewDidLoad
{
// Always call the super implmetaion of viewDidload
[super viewDidLoad];
NSLog(@"HypnosisViewcontroller loaded its view");
}
@end
时间视图控制器.m：
#import "TimeViewController.h"
@implementation TimeViewController
-(IBAction)showCurrentTime:(id)sender
{
NSDate *now = [NSDate date];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setTimeStyle:NSDateFormatterMediumStyle];
[timeLabel setText:[formatter stringFromDate:now]];
[timeLabel2 setText:[formatter stringFromDate:now]];
}
-(id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)bundle
{
// Call the superclass's designated initializer
self = [super initWithNibName:nil
bundle:nil];
//Get a pointer to the application bundle object
// NSBundle *appBundle = [NSBundle mainBundle];
// self = [super initWithNibName:@"TimeViewController"
//bundle:appBundle];
if(self){
//Get the tab bar item
UITabBarItem *tbi = [self tabBarItem];
//Give it a label
[tbi setTitle:@"Time"];
//Create a UIImage from a file
//This will use Time@2x.png on retina display devices
UIImage *i = [UIImage imageNamed:@"Time.png"];
// Put that image on the tab bar item
[tbi setImage:i];
}
return self;
}
-(void)viewDidLoad
{
// Always call the super implmetaion of viewDidload
[super viewDidLoad];
NSLog(@"TimeViewcontroller loaded its view");
// [[self view] setBackgroundColor:[UIColor greenColor]];
}
@end
