Xamarin的iOS内存泄漏无处不在 [英] Xamarin iOS memory leaks everywhere
问题描述
我们一直在使用Xamarin的iOS在过去的8个月开发了多个屏幕，功能，嵌套控件一个不平凡的企业应用程序。我们做我们自己的MVVM拱，跨平台的BLL和放大器; DAL为推荐。我们的Android，甚至我们的BLL / DAL之间共享代码对我们网站的产品被使用。
We've been using Xamarin iOS for the last 8 months and developed a non-trivial enterprise app with many screens, features, nested controls. We've done our own MVVM arch, cross platform BLL & DAL as "recommended". We share code between Android and even our BLL/DAL is used on our web product.
一切都很好，除了目前在项目的发布阶段，我们到处都在发现无法挽回的内存泄漏在基于iOS的应用Xamarin。我们已经遵循了所有的指导方针来解决这一点，但现实情况是，C＃GC和对象 - ARC似乎是在他们彼此叠加在MonoTouch的平台目前的方式不兼容的垃圾收集机制。
All is good except now in release phase of project we discover irreparable memory leaks everywhere in the Xamarin iOS-based app. We've followed all the "guidelines" to resolve this but the reality is that C# GC and Obj-C ARC appear to be incompatible garbage collection mechanisms in the current way they overlay each other in monotouch platform.
我们发现现实情况是，原生对象和管理对象之间的硬周期的可以的发生和常见的任何不平凡的应用程序。这是非常容易这在任何地方使用lambda表达式或手势识别，例如发生。添加在MVVM的复杂性，它几乎是一个保证。小姐只是这些情况和对象的整个图之一将永远不会得到收集。这些图表会吸引其他物体和成长就像一个肿瘤，最终导致内部监督办公室迅速而无情的灭绝。
The reality we've found is that hard cycles between native objects and managed objects WILL occur and FREQUENTLY for any non-trivial app. It's extremely easy for this to happen anywhere you use lambdas or gesture recognizers for example. Add in the complexity of MVVM and it's almost a guarantee. Miss just one of these situations and entire graphs of objects will never get collected. These graphs will lure other objects in and grow like a cancer, eventually resulting in a prompt and merciless extermination by iOS.
Xamarin的回答是这个问题不感兴趣的延期和不切实际的期望的开发者应该避免这些情况。这种认真考虑揭示这个作为垃圾收集Xamarin
Xamarin's answer is an uninterested deferral of the issue and an unrealistic expectation that "devs should avoid these situations". Careful consideration of this reveals this as an admission that Garbage Collection is essentially broken in Xamarin.
实现，我现在是你不吨真的得到垃圾收集在Xamarin的iOS在传统的C＃.NET感。你需要使用保养的垃圾模式实际上得到的GC移动和做自己的工作，而且即便如此，它永远不会是完美的 - 不确定性问题
The realization for me now is that you don't really get "garbage collection" in Xamarin iOS in the traditional c# .NET sense. You need employ "garbage maintanence" patterns actually get the GC moving and doing its job, and even then it'll never be perfect - NON DETERMINISTIC.
我公司已投资发财试图阻止我们的崩溃和/或运行内存的应用程序。我们基本上不得不保养的垃圾明确的模式和递归处理每一个该死的东西在眼前，并落实到应用程序，只是为了阻止崩溃，并有一个可行的产品，我们可以卖。我们的客户支持和宽容，但我们知道这不可能永远保持。我们希望Xamarin有一个专门的团队在这个问题上的工作，并把它钉一劳永逸。看起来并不像它，很遗憾。
My company has invested a fortune trying to stop our app from crashing and/or running out of memory. We've basically had to explicitly and recursively dispose every damn thing in sight and implement garbage maintanence patterns into the app, just to stop the crashes and have a viable product we can sell. Our customers are supportive and tolerant, but we know this cannot hold forever. We are hoping Xamarin have a dedicated team working on this issue and get it nailed once and for all. Doesn't look like it, unfortunately.
问题是，我们的经验异常或写在Xamarin不平凡的企业级应用程序的规则？
Question is, is our experience the exception or the rule for non-trivial enterprise-class apps written in Xamarin?
更新
见DisposeEx方法和解决方案的答复。
See answer for DisposeEx method and solution.
推荐答案
我用下面的扩展方法来解决这些内存泄漏问题。想想安德的游戏最后的战斗场景中，DisposeEx方法是这样的激光器和它的关联各方意见，其连接的对象并配置他们递归和不应该崩溃您的应用程序的方式。
I used the below extension methods to solve these memory leak issues. Think of Ender's Game final battle scene, the DisposeEx method is like that laser and it disassociates all views and their connected objects and disposes them recursively and in a way that shouldn't crash your app.
只需拨打UIViewController的主视图DisposeEx（）当你不再需要一个视图控制器。如果某些嵌套的UIView有特别的东西处理掉，或者你不希望它处理，实施ISpecialDisposable.SpecialDispose被称为到位IDisposable.Dispose的。
Just call DisposeEx() on UIViewController's main view when you no longer need that view controller. If some nested UIView has special things to dispose, or you dont want it disposed, implement ISpecialDisposable.SpecialDispose which is called in place of IDisposable.Dispose.
注意：这不承担任何UIImage的实例，在您的应用程序共享。如果是这样，修改DisposeEx智能处理。
NOTE: this assumes no UIImage instances are shared in your app. If they are, modify DisposeEx to intelligently dispose.
public static void DisposeEx(this UIView view) {
const bool enableLogging = false;
try {
if (view.IsDisposedOrNull())
return;
var viewDescription = string.Empty;
if (enableLogging) {
viewDescription = view.Description;
SystemLog.Debug("Destroying " + viewDescription);
}
var disposeView = true;
var disconnectFromSuperView = true;
var disposeSubviews = true;
var removeGestureRecognizers = false; // WARNING: enable at your own risk, may causes crashes
var removeConstraints = true;
var removeLayerAnimations = true;
var associatedViewsToDispose = new List<UIView>();
var otherDisposables = new List<IDisposable>();
if (view is UIActivityIndicatorView) {
var aiv = (UIActivityIndicatorView)view;
if (aiv.IsAnimating) {
aiv.StopAnimating();
}
} else if (view is UITableView) {
var tableView = (UITableView)view;
if (tableView.DataSource != null) {
otherDisposables.Add(tableView.DataSource);
}
if (tableView.BackgroundView != null) {
associatedViewsToDispose.Add(tableView.BackgroundView);
}
tableView.Source = null;
tableView.Delegate = null;
tableView.DataSource = null;
tableView.WeakDelegate = null;
tableView.WeakDataSource = null;
associatedViewsToDispose.AddRange(tableView.VisibleCells ?? new UITableViewCell[0]);
} else if (view is UITableViewCell) {
var tableViewCell = (UITableViewCell)view;
disposeView = false;
disconnectFromSuperView = false;
if (tableViewCell.ImageView != null) {
associatedViewsToDispose.Add(tableViewCell.ImageView);
}
} else if (view is UICollectionView) {
var collectionView = (UICollectionView)view;
disposeView = false;
if (collectionView.DataSource != null) {
otherDisposables.Add(collectionView.DataSource);
}
if (!collectionView.BackgroundView.IsDisposedOrNull()) {
associatedViewsToDispose.Add(collectionView.BackgroundView);
}
//associatedViewsToDispose.AddRange(collectionView.VisibleCells ?? new UICollectionViewCell[0]);
collectionView.Source = null;
collectionView.Delegate = null;
collectionView.DataSource = null;
collectionView.WeakDelegate = null;
collectionView.WeakDataSource = null;
} else if (view is UICollectionViewCell) {
var collectionViewCell = (UICollectionViewCell)view;
disposeView = false;
disconnectFromSuperView = false;
if (collectionViewCell.BackgroundView != null) {
associatedViewsToDispose.Add(collectionViewCell.BackgroundView);
}
} else if (view is UIWebView) {
var webView = (UIWebView)view;
if (webView.IsLoading)
webView.StopLoading();
webView.LoadHtmlString(string.Empty, null); // clear display
webView.Delegate = null;
webView.WeakDelegate = null;
} else if (view is UIImageView) {
var imageView = (UIImageView)view;
if (imageView.Image != null) {
otherDisposables.Add(imageView.Image);
imageView.Image = null;
}
} else if (view is UIScrollView) {
var scrollView = (UIScrollView)view;
scrollView.UnsetZoomableContentView();
}
var gestures = view.GestureRecognizers;
if (removeGestureRecognizers && gestures != null) {
foreach(var gr in gestures) {
view.RemoveGestureRecognizer(gr);
gr.Dispose();
}
}
if (removeLayerAnimations && view.Layer != null) {
view.Layer.RemoveAllAnimations();
}
if (disconnectFromSuperView && view.Superview != null) {
view.RemoveFromSuperview();
}
var constraints = view.Constraints;
if (constraints != null && constraints.Any() && constraints.All(c => c.Handle != IntPtr.Zero)) {
view.RemoveConstraints(constraints);
foreach(var constraint in constraints) {
constraint.Dispose();
}
}
foreach(var otherDisposable in otherDisposables) {
otherDisposable.Dispose();
}
foreach(var otherView in associatedViewsToDispose) {
otherView.DisposeEx();
}
var subViews = view.Subviews;
if (disposeSubviews && subViews != null) {
subViews.ForEach(DisposeEx);
}
if (view is ISpecialDisposable) {
((ISpecialDisposable)view).SpecialDispose();
} else if (disposeView) {
if (view.Handle != IntPtr.Zero)
view.Dispose();
}
if (enableLogging) {
SystemLog.Debug("Destroyed {0}", viewDescription);
}
} catch (Exception error) {
SystemLog.Exception(error);
}
}
public static void RemoveAndDisposeChildSubViews(this UIView view) {
if (view == null)
return;
if (view.Handle == IntPtr.Zero)
return;
if (view.Subviews == null)
return;
view.Subviews.Update(RemoveFromSuperviewAndDispose);
}
public static void RemoveFromSuperviewAndDispose(this UIView view) {
view.RemoveFromSuperview();
view.DisposeEx();
}
public static bool IsDisposedOrNull(this UIView view) {
if (view == null)
return true;
if (view.Handle == IntPtr.Zero)
return true;;
return false;
}
public interface ISpecialDisposable {
void SpecialDispose();
}
这篇关于Xamarin的iOS内存泄漏无处不在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
