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feihumingyue:
nice 很好啊
JSF中如何使用FacesContext类 -
wgcniler:
请问如果传到存储过程的参数是一个嵌套表的话该怎么写?自定义的o ...
spring中调用存储过程 -
wgcniler:
请问如果传到存储过程的参数是ARRAY,但ARRAY的元素不是 ...
spring中调用存储过程 -
bengan:
谢谢楼上的提示
关于出现僵尸信号SIGBAT或者EXC_BAD_ACCESS的解决方案 -
gypgyp:
用xcode的菜单:product/profile,弹出窗口中 ...
关于出现僵尸信号SIGBAT或者EXC_BAD_ACCESS的解决方案
viewDidUnload viewDidLoad UIViewController内存管理相关的几个方法
viewDidLoad
view载入后的操作有:view显示的一些数据要在此载入,并在viewDidUnload时释放。
viewDidUnload
view释放后的操作有:释放那些view显示时的数据,并在view再次载入内存时也载入这些数据。
所以:获得数据应该是先判定是否存在。不存在再去获取。。这么个思路、
dealloc
Deallocates the memory occupied by the receiver.
- (void)dealloc
Discussion
Subsequent messages to the receiver may generate an error indicating that a message was sent to a deallocated object (provided the deallocated memory hasn’t been reused yet).
You never send a dealloc message directly. Instead, an object’s dealloc method is invoked indirectly through therelease NSObject protocol method (if the release message results in the receiver's retain count becoming 0). SeeMemory Management Programming Guide for more details on the use of these methods.
Subclasses must implement their own versions of dealloc to allow the release of any additional memory consumed by the object—such as dynamically allocated storage for data or object instance variables owned by the deallocated object. After performing the class-specific deallocation, the subclass method should incorporate superclass versions of dealloc through a message to super:
- (void)dealloc {
[companion release];
NSZoneFree(private, [self zone])
[super dealloc];
}
Important: Note that when an application terminates, objects may not be sent a dealloc message since the process’s memory is automatically cleared on exit—it is more efficient simply to allow the operating system to clean up resources than to invoke all the memory management methods. For this and other reasons, you should not manage scarce resources in dealloc—see Object Ownership and Disposal in Memory Management Programming Guide for more details.
didReceiveMemoryWarning
Sent to the view controller when the application receives a memory warning.
- (void)didReceiveMemoryWarning
Discussion
The default implementation of this method checks to see if the view controller can safely release its view. This is possible if the view itself does not have a superview and can be reloaded either from a nib file or using a customloadView method. If the view can be released, this method releases it and calls the viewDidUnload method.
You can override this method (as needed) to release any additional memory used by your view controller. If you do, be sure to call the super implementation at some point to allow the view controller to release its view. In iOS 3.0 and later, if your view controller holds references to objects in the view hierarchy, you should release those references in the viewDidUnload method instead. In earlier versions of iOS, you should continue to release them from this method. See the discussion in the viewDidUnload method for information about how to safely release outlets and other objects.
viewDidUnload
Called when the controller’s view is released from memory.
- (void)viewDidUnload
Discussion
This method is called as a counterpart to the viewDidLoad method. It is called during low-memory conditions when the view controller needs to release its view and any objects associated with that view to free up memory. Because view controllers often store references to views and other view-related objects, you should use this method to relinquish ownership in those objects so that the memory for them can be reclaimed. You should do this only for objects that you can easily recreate later, either in your viewDidLoad method or from other parts of your application. You should not use this method to release user data or any other information that cannot be easily recreated.
Typically, a view controller stores references to objects using an outlet, which is a variable or property that includes the IBOutlet keyword and is configured using Interface Builder. A view controller may also store pointers to objects that it creates programmatically, such as in the viewDidLoad method. The preferred way to relinquish ownership of any object (including those in outlets) is to use the corresponding accessor method to set the value of the object tonil. However, if you do not have an accessor method for a given object, you may have to release the object explicitly. For more information about memory management practices, see Memory Management Programming Guide.
By the time this method is called, the view property is nil.
Special Considerations
If your view controller stores references to views and other custom objects, it is also responsible for relinquishing ownership of those objects safely in its dealloc method. If you implement this method but are building your application for iOS 2.x, your dealloc method should release each object but should also set the reference to that object to nil before calling super.
viewDidLoad
view载入后的操作有:view显示的一些数据要在此载入,并在viewDidUnload时释放。
viewDidUnload
view释放后的操作有:释放那些view显示时的数据,并在view再次载入内存时也载入这些数据。
所以:获得数据应该是先判定是否存在。不存在再去获取。。这么个思路、
dealloc
Deallocates the memory occupied by the receiver.
- (void)dealloc
Discussion
Subsequent messages to the receiver may generate an error indicating that a message was sent to a deallocated object (provided the deallocated memory hasn’t been reused yet).
You never send a dealloc message directly. Instead, an object’s dealloc method is invoked indirectly through therelease NSObject protocol method (if the release message results in the receiver's retain count becoming 0). SeeMemory Management Programming Guide for more details on the use of these methods.
Subclasses must implement their own versions of dealloc to allow the release of any additional memory consumed by the object—such as dynamically allocated storage for data or object instance variables owned by the deallocated object. After performing the class-specific deallocation, the subclass method should incorporate superclass versions of dealloc through a message to super:
- (void)dealloc {
[companion release];
NSZoneFree(private, [self zone])
[super dealloc];
}
Important: Note that when an application terminates, objects may not be sent a dealloc message since the process’s memory is automatically cleared on exit—it is more efficient simply to allow the operating system to clean up resources than to invoke all the memory management methods. For this and other reasons, you should not manage scarce resources in dealloc—see Object Ownership and Disposal in Memory Management Programming Guide for more details.
didReceiveMemoryWarning
Sent to the view controller when the application receives a memory warning.
- (void)didReceiveMemoryWarning
Discussion
The default implementation of this method checks to see if the view controller can safely release its view. This is possible if the view itself does not have a superview and can be reloaded either from a nib file or using a customloadView method. If the view can be released, this method releases it and calls the viewDidUnload method.
You can override this method (as needed) to release any additional memory used by your view controller. If you do, be sure to call the super implementation at some point to allow the view controller to release its view. In iOS 3.0 and later, if your view controller holds references to objects in the view hierarchy, you should release those references in the viewDidUnload method instead. In earlier versions of iOS, you should continue to release them from this method. See the discussion in the viewDidUnload method for information about how to safely release outlets and other objects.
viewDidUnload
Called when the controller’s view is released from memory.
- (void)viewDidUnload
Discussion
This method is called as a counterpart to the viewDidLoad method. It is called during low-memory conditions when the view controller needs to release its view and any objects associated with that view to free up memory. Because view controllers often store references to views and other view-related objects, you should use this method to relinquish ownership in those objects so that the memory for them can be reclaimed. You should do this only for objects that you can easily recreate later, either in your viewDidLoad method or from other parts of your application. You should not use this method to release user data or any other information that cannot be easily recreated.
Typically, a view controller stores references to objects using an outlet, which is a variable or property that includes the IBOutlet keyword and is configured using Interface Builder. A view controller may also store pointers to objects that it creates programmatically, such as in the viewDidLoad method. The preferred way to relinquish ownership of any object (including those in outlets) is to use the corresponding accessor method to set the value of the object tonil. However, if you do not have an accessor method for a given object, you may have to release the object explicitly. For more information about memory management practices, see Memory Management Programming Guide.
By the time this method is called, the view property is nil.
Special Considerations
If your view controller stores references to views and other custom objects, it is also responsible for relinquishing ownership of those objects safely in its dealloc method. If you implement this method but are building your application for iOS 2.x, your dealloc method should release each object but should also set the reference to that object to nil before calling super.
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iOS 监听音量调节 事件
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2012-08-23 01:19 1136转载自 http://stackoverflow.com/qu ... -
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UIVideoEditorController 使用
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iphone app 四种崩溃类型
2012-07-17 22:42 1130一.四种崩溃类型 程序崩溃: 可能是最常见的,经常发生于内存 ... -
首先查看crash log中的崩溃线程
2012-07-15 15:47 1860首先查看crash log中的崩溃线程,假如是这样的: Th ... -
iOS【EXC_BAD_ACCESS 】crash报告分析
2012-07-15 15:40 7925做iOS的开发者,经常都会遇到这个问题,我在这里做一下简单的分 ... -
objective-c aes加密
2012-05-11 11:21 3608在cocoa看到的加密代码,介绍一下。 aes加密的,1M的数 ... -
NSObject类所支持的一些基本方法
2012-04-10 14:33 1350NSObject类所支持的一些基本方法 对象是否class- ... -
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2012-03-31 11:52 2206关于出现僵尸信号SIGBAT或者EXC_BAD_ACCESS的 ... -
Xcode4.2新特性之storyboards (故事板)
2012-03-31 11:43 4337Xcode4.2新特性之storyboards ... -
iPhone OS体系结构
2012-03-29 07:43 1657iPhone OS体系结构 iPhone OS有着绚丽优雅的外 ... -
iPhone的软件栈分成好几层
2012-03-29 07:01 1210iPhone的软件栈分成好几层。应用程序位于最高的抽象层,而系 ... -
UIImagePickerController使用
2012-03-17 22:47 4273UIImagePickerController使用 引用UI ... -
wait_fences: failed to receive reply: 10004003奇怪的错误
2012-03-17 11:09 2737今日遇到wait_fences: failed to rece ... -
iphone app 本地化程序名称
2012-03-17 01:38 910本地化程序名称 1、 建立InfoPlist.strings ... -
iphone app 为图片添加边框
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objective-c 内存管理的文章摘录2
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Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
PiP-Tool
Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
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Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
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Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
第八节.py
Node.js,简称Node,是一个开源且跨平台的JavaScript运行时环境,它允许在浏览器外运行JavaScript代码。Node.js于2009年由Ryan Dahl创立,旨在创建高性能的Web服务器和网络应用程序。它基于Google Chrome的V8 JavaScript引擎,可以在Windows、Linux、Unix、Mac OS X等操作系统上运行。 Node.js的特点之一是事件驱动和非阻塞I/O模型,这使得它非常适合处理大量并发连接,从而在构建实时应用程序如在线游戏、聊天应用以及实时通讯服务时表现卓越。此外,Node.js使用了模块化的架构,通过npm(Node package manager,Node包管理器),社区成员可以共享和复用代码,极大地促进了Node.js生态系统的发展和扩张。 Node.js不仅用于服务器端开发。随着技术的发展,它也被用于构建工具链、开发桌面应用程序、物联网设备等。Node.js能够处理文件系统、操作数据库、处理网络请求等,因此,开发者可以用JavaScript编写全栈应用程序,这一点大大提高了开发效率和便捷性。 在实践中,许多大型企业和组织已经采用Node.js作为其Web应用程序的开发平台,如Netflix、PayPal和Walmart等。它们利用Node.js提高了应用性能,简化了开发流程,并且能更快地响应市场需求。
svg,真的好像!!!