iPhone Memory Debugging with NSZombie and Instruments

最新推荐文章于 2016-06-01 13:56:03 发布

转载最新推荐文章于 2016-06-01 13:56:03 发布 · 118 阅读

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原文链接：http://www.cnblogs.com/ynwlgh/archive/2011/12/06/2277743.html

本文介绍使用Instruments工具中的NSZombie功能定位并解决iPhone应用因对象已删除而调用方法导致的BAD_ACCESS内存错误。通过运行'ObjectAllocations'性能工具，启用NSZombie检测和记录引用计数，可在应用崩溃时获取问题对象的完整内存历史。

When your iPhone app crashes with ‘BAD ACCESS’ you’re in trouble – a memory bug where you tried to call a method on a object that was already deleted. Instruments has support for NSZombie – a feature that makes it easy to find the source of the bug by showing you a full history of every alloc, retain, release, and autorelease of the object that caused the crash! Wow. Here’s how:

Basic steps are:

Run in Performance tool ‘Object Allocations’
Stop running and set options on ObjAllocations instrument: ‘Enable NSZombie’ Detection and ‘Record Reference Counts’
Re-run from instruments, when it crashes, click the arrow in the popup zombie dialog
Open up the stack trace view and see the full memory history of the problem object
Wow, how awesome is that?
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You might also like my memory management tutorial and other posts under ‘App Development’.

Here’s a link to the demo program: ZombieDebug Demo Project. The code we’re looking at in the video is:

@implementation ZombieDebugViewController

@synthesize objArray;

-(void)rewriteText {
NSMutableString* s = [NSMutableString stringWithCapacity:100];
for (id obj in objArray) {
[s appendFormat:@"%@,\n",obj];
[obj release];
}
label.text = s;
}

- (void)viewDidLoad {
[super viewDidLoad];
self.objArray = [NSMutableArray arrayWithCapacity:10];
[objArray addObject:@"I'm a string object"];
[self rewriteText];
}

-(IBAction) tapButton:(id)button {
NSNumber* n = [NSNumber numberWithLong:random()];
[objArray addObject:n];
[self rewriteText];
}

-(void)dealloc {
[super dealloc];
self.objArray=nil;
}

@end

转载于:https://www.cnblogs.com/ynwlgh/archive/2011/12/06/2277743.html