多次分配和释放时间

Question

我正在为 iPhone/iPad 创建一个测验应用程序（通用应用程序）。它在模拟器上工作正常，但在真实设备上我遇到了一些问题。

• 我正在以编程方式创建 UILabels 和 UIButtons，并且我多次使用它们一一显示问题和答案。

问题是当我遇到问题 20 到 22 时，应用程序崩溃了。我不知道为什么。我没有发现内存泄漏。我在 -dealloc 函数中释放了所有标签和按钮。
可能会发生这种情况，因为 22 个问题占用了一些内存，直到调用 dealloc 函数后才释放。

我想要的是，有没有办法在每个问题后释放标签和按钮，然后它会再次分配？或者我可以使用更少的内存来分配标签和按钮的任何方式？

我正在使用这段代码：

//lbl ref to btn1
ans1 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 292, 697, 100)] autorelease];
ans1.numberOfLines = 0;
ans1.font = [UIFont systemFontOfSize:26];
ans1.text = [theQuiz objectAtIndex:row+1];
ans1.lineBreakMode = UILineBreakModeWordWrap;
[ans1 sizeToFit];
//[self.view addSubview:ans1];
//lbl ref to btn2
ans2 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 312 + ans1.frame.size.height , 697, 100)] autorelease];
ans2.numberOfLines = 0;
ans2.font = [UIFont systemFontOfSize:26];
ans2.text = [theQuiz objectAtIndex:row+2];
ans2.lineBreakMode = UILineBreakModeWordWrap;
[ans2 sizeToFit];
// [self.view addSubview:ans2];
//lbl ref to btn3
ans3 = [[[UILabel alloc] initWithFrame:CGRectMake(36 ,332 + ans1.frame.size.height + ans2.frame.size.height , 697 , 100)] autorelease];
ans3.numberOfLines = 0;
ans3.font = [UIFont systemFontOfSize:26];
ans3.text = [theQuiz objectAtIndex:row+3] ;
ans3.lineBreakMode = UILineBreakModeWordWrap;
[ans3 sizeToFit];
// [self.view addSubview:ans3];
//lbl ref to btn4
ans4 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 352 + ans1.frame.size.height + ans2.frame.size.height + ans3.frame.size.height, 697, 100)] autorelease];
ans4.numberOfLines = 0;
ans4.font = [UIFont systemFontOfSize:26];
ans4.text = [theQuiz objectAtIndex:row+4];
ans4.lineBreakMode = UILineBreakModeWordWrap;
[ans4 sizeToFit];
// [self.view addSubview:ans4];

rightAnswer = [[theQuiz objectAtIndex:row+5] intValue];

Question = [[[UILabel alloc] initWithFrame:CGRectMake(22, 130, 725, 160)] autorelease];
Question.numberOfLines = 0;
//Question.font = [UIFont systemFontOfSize:27];
Question.text = [NSString stringWithFormat:@"%@" ,selected1];
Question.lineBreakMode = UILineBreakModeWordWrap;
[Question setFont:[UIFont fontWithName:@"Futura" size:26]];
Question.backgroundColor = [UIColor clearColor];
[Question sizeToFit];
[self.view addSubview:Question];

//For 1st Option.
button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self 
           action:@selector(buttonOne)
 forControlEvents:UIControlEventTouchDown];
button.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button.titleLabel.font = [UIFont systemFontOfSize:24];
[button setTitle:[theQuiz objectAtIndex:row+1] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.frame = CGRectMake(34, 200 + Question.frame.size.height , 700, ans1.frame.size.height + 20) ;
[self.view addSubview:button];
button.layer.borderWidth = 3;
button.layer.borderColor = [[UIColor purpleColor ] CGColor];
button.layer.cornerRadius = 10.0;
[button setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For 2nd Option.
button2 = [UIButton buttonWithType:UIButtonTypeCustom];
[button2 addTarget:self 
            action:@selector(buttonTwo)
  forControlEvents:UIControlEventTouchDown];
[button2 setTitle:[theQuiz objectAtIndex:row+2] forState:UIControlStateNormal];
[button2 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button2.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button2.titleLabel.font = [UIFont systemFontOfSize:24];
button2.frame = CGRectMake(34, 230 + Question.frame.size.height + button.frame.size.height , 700, ans2.frame.size.height + 20);
button2.layer.borderWidth = 3;
button2.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button2.layer.cornerRadius = 10.0;
[self.view addSubview:button2];
[button2 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button2.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For 3rd Option.
button3 = [UIButton buttonWithType:UIButtonTypeCustom];
[button3 addTarget:self 
            action:@selector(buttonThree)
  forControlEvents:UIControlEventTouchDown];
[button3 setTitle:[theQuiz objectAtIndex:row+3] forState:UIControlStateNormal];
[button3 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button3.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button3.titleLabel.font = [UIFont systemFontOfSize:24];
button3.frame = CGRectMake(34, 260 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height , 700, ans3.frame.size.height + 20);
button3.layer.borderWidth = 3;
button3.layer.borderColor = [[UIColor purpleColor ] CGColor];
button3.layer.cornerRadius = 10.0;

[self.view addSubview:button3];
[button3 setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button3.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For 4th Option.
button4 = [UIButton buttonWithType:UIButtonTypeCustom];
[button4 addTarget:self 
            action:@selector(buttonFour)
  forControlEvents:UIControlEventTouchDown];
[button4 setTitle:[theQuiz objectAtIndex:row+4] forState:UIControlStateNormal];
[button4 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button4.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button4.titleLabel.font = [UIFont systemFontOfSize:24];
button4.frame = CGRectMake(34, 290 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height + button3.frame.size.height , 700, ans4.frame.size.height + 20);
button4.layer.borderWidth = 3;
button4.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button4.layer.cornerRadius = 10.0;
[self.view addSubview:button4];
[button4 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button4.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

NSString *strright = [theQuiz objectAtIndex:row+7];
//NSString *strtext = [[NSString alloc] initWithFormat:@"%@" , strright];

rightans = [[[UILabel alloc] initWithFrame:CGRectMake(50, 330, 650, 150)]autorelease];
rightans.numberOfLines = 0;
rightans.text = [NSString stringWithFormat:@"%@" , strright];
rightans.backgroundColor = [UIColor clearColor];
rightans.font = [UIFont systemFontOfSize:26];
[self.view addSubview:rightans];
[rightans sizeToFit];
[rightans setHidden:YES];

//Description.
NSString *des = [theQuiz objectAtIndex:row+6];
//  NSString *destext = [[NSString alloc] initWithFormat:@"\n> Explanation :\n%@\n\n" , des];

Description = [[[UILabel alloc] initWithFrame:CGRectMake(40, 400 + rightans.frame.size.height , 690, 150)] autorelease];
Description.numberOfLines = 0;
// Description.font = [UIFont systemFontOfSize:13.5];
Description.text = [NSString stringWithFormat:@"\n> Explanation :\n%@\n\n" , des];
[Description setFont:[UIFont fontWithName:@"Futura" size:26]];
Description.lineBreakMode = UILineBreakModeWordWrap;
Description.backgroundColor = [UIColor clearColor];
[Description sizeToFit];
[self.view addSubview:Description];
[Description setHidden:YES];


ContainerView = [[UIView alloc] initWithFrame:CGRectMake(30, 400 + rightans.frame.size.height , 700 ,Description.frame.size.height)];
ContainerView.backgroundColor = [UIColor clearColor];
ContainerView.layer.cornerRadius = 10.0;
ContainerView.layer.borderColor = [[UIColor grayColor] CGColor];
ContainerView.layer.borderWidth = 3;
// [ContainerView addSubview:Description];
[self.view addSubview:ContainerView];
[ContainerView setHidden:YES];

有什么帮助吗？
谢谢。

Answer 1

您不应该释放自动释放对象。

Answer 2

1. 一旦您将标签作为子视图添加到视图中 - 视图将保留您可以释放标签的标签，在您的情况下，您不会释放 ContainerView
2. 您不应该释放自动释放的对象 - 没关系

Answer 3

首先，您应该在使用 [self.view addSubview: myObj] 将对象添加到视图后立即释放该对象。当您添加这样的对象时，其保留计数会根据父视图和父视图的数量而增加。您应该释放它（以减少其保留计数）以允许其垃圾回收。你的代码应该是这样的 -

[self.view addSubview: myObj];
[myObj release];

其次，你有崩溃日志吗？

HTH，

阿克谢

Answer 4

1）简单的规则，您释放您分配或保留、复制的任何内容...您拥有的所有其他变量都将自动释放。在您的代码中，您分配了所有标签，但没有分配按钮。将其添加到子视图后，您必须释放所有标签。您只需添加到子视图中的按钮，不会释放后记，因为您没有分配它。.既然您在问 类似的问题 2 天我刚刚研究了你的代码

//lbl ref to btn1
ans1 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 292, 697, 100)] autorelease];
ans1.numberOfLines = 0;
ans1.font = [UIFont systemFontOfSize:26];
ans1.text = [theQuiz objectAtIndex:row+1];
ans1.lineBreakMode = UILineBreakModeWordWrap;
[ans1 sizeToFit];
[self.view addSubview:ans1];


//lbl ref to btn2
ans2 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 312 + ans1.frame.size.height , 697, 100)] autorelease];
ans2.numberOfLines = 0;
ans2.font = [UIFont systemFontOfSize:26];
ans2.text = [theQuiz objectAtIndex:row+2];
ans2.lineBreakMode = UILineBreakModeWordWrap;
[ans2 sizeToFit];
[self.view addSubview:ans2];


//lbl ref to btn3
ans3 = [[[UILabel alloc] initWithFrame:CGRectMake(36 ,332 + ans1.frame.size.height + ans2.frame.size.height , 697 , 100)] autorelease];
ans3.numberOfLines = 0;
ans3.font = [UIFont systemFontOfSize:26];
ans3.text = [theQuiz objectAtIndex:row+3] ;
ans3.lineBreakMode = UILineBreakModeWordWrap;
[ans3 sizeToFit];
[self.view addSubview:ans3];


//lbl ref to btn4
ans4 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 352 + ans1.frame.size.height + ans2.frame.size.height + ans3.frame.size.height, 697, 100)] autorelease];
ans4.numberOfLines = 0;
ans4.font = [UIFont systemFontOfSize:26];
ans4.text = [theQuiz objectAtIndex:row+4];
ans4.lineBreakMode = UILineBreakModeWordWrap;
[ans4 sizeToFit];
[self.view addSubview:ans4];

rightAnswer = [[theQuiz objectAtIndex:row+5] intValue];

Question = [[[UILabel alloc] initWithFrame:CGRectMake(22, 130, 725, 160)] autorelease];
Question.numberOfLines = 0;
//Question.font = [UIFont systemFontOfSize:27];
Question.text = [NSString stringWithFormat:@"%@" ,selected1];
Question.lineBreakMode = UILineBreakModeWordWrap;
[Question setFont:[UIFont fontWithName:@"Futura" size:26]];
Question.backgroundColor = [UIColor clearColor];
[Question sizeToFit];
[self.view addSubview:Question];

//For 1st Option.
button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self action:@selector(buttonOne) forControlEvents:UIControlEventTouchDown];
button.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button.titleLabel.font = [UIFont systemFontOfSize:24];
[button setTitle:[theQuiz objectAtIndex:row+1] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.frame = CGRectMake(34, 200 + Question.frame.size.height , 700, ans1.frame.size.height + 20) ;
button.layer.borderWidth = 3;
button.layer.borderColor = [[UIColor purpleColor ] CGColor];
button.layer.cornerRadius = 10.0;
[button setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button];



//For 2nd Option.
button2 = [UIButton buttonWithType:UIButtonTypeCustom];
[button2 addTarget:self action:@selector(buttonTwo) forControlEvents:UIControlEventTouchDown];
[button2 setTitle:[theQuiz objectAtIndex:row+2] forState:UIControlStateNormal];
[button2 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button2.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button2.titleLabel.font = [UIFont systemFontOfSize:24];
button2.frame = CGRectMake(34, 230 + Question.frame.size.height + button.frame.size.height , 700, ans2.frame.size.height + 20);
button2.layer.borderWidth = 3;
button2.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button2.layer.cornerRadius = 10.0;
[button2 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button2.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button2];


//For 3rd Option.
button3 = [UIButton buttonWithType:UIButtonTypeCustom];
[button3 addTarget:self action:@selector(buttonThree) forControlEvents:UIControlEventTouchDown];
[button3 setTitle:[theQuiz objectAtIndex:row+3] forState:UIControlStateNormal];
[button3 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button3.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button3.titleLabel.font = [UIFont systemFontOfSize:24];
button3.frame = CGRectMake(34, 260 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height , 700, ans3.frame.size.height + 20);
button3.layer.borderWidth = 3;
button3.layer.borderColor = [[UIColor purpleColor ] CGColor];
button3.layer.cornerRadius = 10.0;
[button3 setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button3.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button3];



//For 4th Option.
button4 = [UIButton buttonWithType:UIButtonTypeCustom];
[button4 addTarget:self action:@selector(buttonFour) forControlEvents:UIControlEventTouchDown];
[button4 setTitle:[theQuiz objectAtIndex:row+4] forState:UIControlStateNormal];
[button4 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button4.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button4.titleLabel.font = [UIFont systemFontOfSize:24];
button4.frame = CGRectMake(34, 290 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height + button3.frame.size.height , 700, ans4.frame.size.height + 20);
button4.layer.borderWidth = 3;
button4.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button4.layer.cornerRadius = 10.0;
[button4 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button4.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button4];



NSString *strright = [theQuiz objectAtIndex:row+7];
//NSString *strtext = [[NSString alloc] initWithFormat:@"%@" , strright];



rightans = [[[UILabel alloc] initWithFrame:CGRectMake(50, 330, 650, 150)]autorelease];
rightans.numberOfLines = 0;
rightans.text = [NSString stringWithFormat:@"%@" , strright];
rightans.backgroundColor = [UIColor clearColor];
rightans.font = [UIFont systemFontOfSize:26];
[rightans sizeToFit];
[rightans setHidden:YES];
[self.view addSubview:rightans];


//Description.
NSString *des = [theQuiz objectAtIndex:row+6];
//  NSString *destext = [[NSString alloc] initWithFormat:@"\n> Explanation :\n%@\n\n" , des];


Description = [[[UILabel alloc] initWithFrame:CGRectMake(40, 400 + rightans.frame.size.height , 690, 150)] autorelease];
Description.numberOfLines = 0;
// Description.font = [UIFont systemFontOfSize:13.5];
Description.text = [NSString stringWithFormat:@"\n> Explanation :\n%@\n\n" , des];
[Description setFont:[UIFont fontWithName:@"Futura" size:26]];
Description.lineBreakMode = UILineBreakModeWordWrap;
Description.backgroundColor = [UIColor clearColor];
[Description sizeToFit];
[Description setHidden:YES];
[self.view addSubview:Description];



ContainerView = [[UIView alloc] initWithFrame:CGRectMake(30, 400 + rightans.frame.size.height , 700 ,Description.frame.size.height)];
ContainerView.backgroundColor = [UIColor clearColor];
ContainerView.layer.cornerRadius = 10.0;
ContainerView.layer.borderColor = [[UIColor grayColor] CGColor];
ContainerView.layer.borderWidth = 3;
// [ContainerView addSubview:Description];
[ContainerView setHidden:YES];
[self.view addSubview:ContainerView];
[ContainerView release];

还有其他一些注意点。

1）变量名应该总是以小写字母开头。这不是一个书面规则，而是一个很好的实践，对你自己和其他人（比如我们）来说更容易审查它。像“描述”和“问题”这样的变量名不好。

2）永远不要重新发布你的问题..如果你只是更好地格式化代码，你应该在上一个问题本身中得到答案。