我有一个包含多个视图的应用。其中一个视图始终可见。所有视图都由视图工厂缓存，因此每个视图只有一个实例。用户可以在视图之间导航。在这样的导航过程中，我从工厂获取目标视图并将其设置为页面内容。大多数观点都非常微不足道;其他（也是微不足道的，但是）包含最多100-120个项目的列表（通常是~20-30）。当我在视图之间多次切换（比方说13，但无论如何）时，应用程序崩溃了OutOfMemoryError并使用以下堆栈跟踪：
Java.Lang.OutOfMemoryError:
at at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <IL 0x00011, 0x00078>
at Android.Runtime.JNIEnv.CallStaticObjectMethod (intptr,intptr,Android.Runtime.JValue*) [0x00064] in /Users/builder/data/lanes/1879/5f55a9ef/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:1301
at Android.Graphics.Bitmap.CreateBitmap (int,int,Android.Graphics.Bitmap/Config) [0x0006c] in /Users/builder/data/lanes/1879/5f55a9ef/source/monodroid/src/Mono.Android/platforms/android-21/src/generated/Android.Graphics.Bitmap.cs:715
at at Xamarin.Forms.Platform.Android.ButtonDrawable.CreateBitmap (bool,int,int) <IL 0x00007, 0x0008f>
at at Xamarin.Forms.Platform.Android.ButtonDrawable.Draw (Android.Graphics.Canvas) <IL 0x00056, 0x0026b>
at Android.Graphics.Drawables.Drawable.n_Draw_Landroid_graphics_Canvas_ (intptr,intptr,intptr) [0x00011] in /Users/builder/data/lanes/1879/5f55a9ef/source/monodroid/src/Mono.Android/platforms/android-21/src/generated/Android.Graphics.Drawables.Drawable.cs:1382
at at (wrapper dynamic-method) object.c46054a1-7b98-454c-9938-fe7e0c262669 (intptr,intptr,intptr) <IL 0x00017, 0x00043>
at --- End of managed exception stack trace ---
at java.lang.OutOfMemoryError
at at android.graphics.Bitmap.nativeCreate(Native Method)
at at android.graphics.Bitmap.createBitmap(Bitmap.java:726)
at at android.graphics.Bitmap.createBitmap(Bitmap.java:703)
at at android.graphics.Bitmap.createBitmap(Bitmap.java:670)
at at md5530bd51e982e6e7b340b73e88efe666e.ButtonDrawable.n_draw(Native Method)
at at md5530bd51e982e6e7b340b73e88efe666e.ButtonDrawable.draw(ButtonDrawable.java:49)
at at android.view.View.draw(View.java:14838)
at at android.view.View.getDisplayList(View.java:13744)
at at android.view.View.getDisplayList(View.java:13786)
at at android.view.View.draw(View.java:14563)
at at android.view.ViewGroup.drawChild(ViewGroup.java:3316)
at at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3153)
....
at at android.view.View.draw(View.java:14563)
at at android.view.ViewGroup.drawChild(ViewGroup.java:3316)
at at android.widget.ListView.drawChild(ListView.java:3390)
at at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3153)
at at android.widget.AbsListView.dispatchDraw(AbsListView.java:2810)
at at android.widget.ListView.dispatchDraw(ListView.java:3385)
at at android.view.View.draw(View.java:14856)
at at android.widget.AbsListView.draw(AbsListView.java:5051)
at at android.view.View.getDisplayList(View.java:13744)
at at android.view.View.getDisplayList(View.java:13786)
at at android.view.View.draw(View.java:14563)
at at android.view.ViewGroup.drawChild(ViewGroup.java:3316)
at at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3160)
at at android.view.View.draw(View.java:14856)
...
at at android.widget.FrameLayout.draw(FrameLayout.java:467)
at at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2621)
at at android.view.View.getDisplayList(View.java:13744)
at at android.view.View.getDisplayList(View.java:13786)
at at android.view.HardwareRenderer$GlRenderer.buildDisplayList(HardwareRenderer.java:1411)
at at android.view.HardwareRenderer$GlRenderer.draw(HardwareRenderer.java:1359)
at at android.view.ViewRootImpl.draw(ViewRootImpl.java:2672)
at at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2538)
at at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2154)
at at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1249)
at at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6364)
at at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791)
at at android.view.Choreographer.doCallbacks(Choreographer.java:591)
at at android.view.Choreographer.doFrame(Choreographer.java:561)
at at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777)
at at android.os.Handler.handleCallback(Handler.java:730)
at at android.os.Handler.dispatchMessage(Handler.java:92)
at at android.os.Looper.loop(Looper.java:176)
at at android.app.ActivityThread.main(ActivityThread.java:5419)
at at java.lang.reflect.Method.invokeNative(Native Method)
at at java.lang.reflect.Method.invoke(Method.java:525)
at at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
at at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
at at dalvik.system.NativeStart.main(Native Method)
首先，我没有猜测，我可以在哪里发布memleak。我想简介一下，但是分析器对我不起作用 - 当我开始分析构建发生时，部署顺利，分析器启动并建议选择我想要分析的内容（分配，时间或一起），但是.... 没有。该应用程序无法启动...
二。我使用基于桌面WPF的应用程序共享业务逻辑（实际上除了视图和一些NFC和USB主机相关的东西）。我介绍了WPF应用程序，我看到没有memleaks。
第三。我总是得到相同的堆栈跟踪，这让我觉得它与绘图引擎有某种关系。实际上Xamarin.Forms.Platform.Android.ButtonDrawable.CreateBitmap可以做什么？我在视图上有按钮（发生崩溃），但所有这些都是透明的，没有任何文本（我以这种方式为列表项创建命令绑定，我的所有项目都有自定义绘图）。那么为什么位图会创建？
四。我非常积极地使用两种自定义字体 - 实际上每个图标或文本都是使用自定义字体绘制的。它能以某种方式影响内存使用吗？
据我所知，我没有提供有关应用程序的更多信息，但应用程序本身非常大，我不知道什么对进一步调查有用。如果需要，我会提供任何细节。
更新 我刚从列表中删除了隐形按钮，可以看出差异。我不能再崩溃应用了，这很好。但是，我可以看到每次启动时GC都会花费越来越多的时间。
从“灯光”视图切换到“重磅”时，我可以看到这一点：
[Mono] GC_OLD_BRIDGE num-objects 37 num_hash_entries 206088 sccs size 39800 init 0.00ms df1 451.67ms sort 176.32ms dfs2 128.80ms setup-cb 23.45ms free-data 181.87ms links 402547/402547/437282/11 dfs passes 608672/442347
[Mono] GC_MINOR: (Nursery full) pause 465.29ms, total 465.37ms, bridge 753.02ms promoted 48K major 19904K los 932K
当我从上到下滚动列表时，会发生几个GC：
[Mono] GC_OLD_BRIDGE num-objects 40 num_hash_entries 207056 sccs size 39767 init 0.00ms df1 498.18ms sort 219.27ms dfs2 143.32ms setup-cb 34.37ms free-data 232.57ms links 404545/404545/278080/7 dfs passes 611641/444312
[Mono] GC_MINOR: (Nursery full) pause 517.30ms, total 517.39ms, bridge 847.48ms promoted 1216K major 21120K los 932K
[Mono] GC_OLD_BRIDGE num-objects 4 num_hash_entries 4 sccs size 4 init 0.00ms df1 0.37ms sort 0.02ms dfs2 0.09ms setup-cb 0.00ms free-data 0.03ms links 0/0/0/0 dfs passes 8/4
[Mono] GC_MINOR: (Nursery full) pause 12.04ms, total 12.27ms, bridge 201.26ms promoted 176K major 21296K los 1060K
[Mono] GC_OLD_BRIDGE num-objects 4 num_hash_entries 4 sccs size 4 init 0.00ms df1 0.37ms sort 0.01ms dfs2 0.09ms setup-cb 0.01ms free-data 0.03ms links 0/0/0/0 dfs passes 8/4
[Mono] GC_MINOR: (Nursery full) pause 12.29ms, total 12.61ms, bridge 197.53ms promoted 240K major 21536K los 1188K
[Mono] GC_OLD_BRIDGE num-objects 2 num_hash_entries 2 sccs size 2 init 0.00ms df1 0.25ms sort 0.00ms dfs2 0.03ms setup-cb 0.00ms free-data 0.05ms links 0/0/0/0 dfs passes 4/2
[Mono] GC_MINOR: (Nursery full) pause 13.00ms, total 13.22ms, bridge 228.32ms promoted 304K major 21840K los 1253K
[Mono] GC_OLD_BRIDGE num-objects 4 num_hash_entries 4 sccs size 4 init 0.00ms df1 0.10ms sort 0.01ms dfs2 0.07ms setup-cb 0.01ms free-data 0.04ms links 0/0/0/0 dfs passes 8/4
[Mono] GC_MINOR: (Nursery full) pause 8.67ms, total 8.76ms, bridge 248.72ms promoted 256K major 22096K los 1381K
[Choreographer] Skipped 32 frames! The application may be doing too much work on its main thread.
[Mono] GC_OLD_BRIDGE num-objects 7 num_hash_entries 207346 sccs size 39934 init 0.00ms df1 437.00ms sort 193.84ms dfs2 90.03ms setup-cb 23.20ms free-data 171.41ms links 404973/404973/39927/1 dfs passes 612326/444907
[Mono] GC_MINOR: (Nursery full) pause 454.99ms, total 455.17ms, bridge 670.38ms promoted 1968K major 24064K los 1381K
[Choreographer] Skipped 71 frames! The application may be doing too much work on its main thread.
[Mono] GC_OLD_BRIDGE num-objects 3 num_hash_entries 207888 sccs size 39951 init 0.00ms df1 486.86ms sort 171.43ms dfs2 92.86ms setup-cb 23.51ms free-data 165.43ms links 406088/406088/79893/2 dfs passes 613979/446039
[Mono] GC_MINOR: (Nursery full) pause 511.48ms, total 511.60ms, bridge 649.23ms promoted 2304K major 26368K los 1381K
[Choreographer] Skipped 75 frames! The application may be doing too much work on its main thread.