如何在 OutOfMemoryError 使我的應用程序崩潰之前捕獲它？

Question

我編寫了一個 android 應用程序，在其中實現了一個求解器。 求解器分配了大量內存。 對於簡單的問題，它可以毫無問題地工作。 但是當問題變得更復雜時，我收到錯誤“2164 字節分配的內存不足”並且應用程序崩潰。

我試着用

try {
        solver();
}
catch (Exception e) {
}

但這並不能阻止應用程序崩潰。

我還在 AndroidManifest.xml 中嘗試了"android:largeHeap="true" 。

有沒有辦法在內存滿之前獲得更多內存或停止求解器？

04-18 11:39:10.953: D/dalvikvm(979): GC_FOR_ALLOC freed 25K, 5% free 31446K/32768K, paused 363ms, total 363ms
04-18 11:39:10.953: I/dalvikvm-heap(979): Forcing collection of SoftReferences for 93404-byte allocation
04-18 11:39:11.283: I/dalvikvm-heap(979): Clamp target GC heap from 32.832MB to 32.000MB
04-18 11:39:11.293: D/dalvikvm(979): GC_BEFORE_OOM freed <1K, 5% free 31445K/32768K, paused 331ms, total 332ms
04-18 11:39:11.293: E/dalvikvm-heap(979): Out of memory on a 93404-byte allocation.
04-18 11:39:11.293: I/dalvikvm(979): "AdWorker #1" prio=5 tid=11 RUNNABLE
04-18 11:39:11.293: I/dalvikvm(979):   | group="main" sCount=0 dsCount=0 obj=0xb48db908 self=0xb7ecf560
04-18 11:39:11.293: I/dalvikvm(979):   | sysTid=1015 nice=10 sched=0/0 cgrp=apps/bg_non_interactive handle=-1209206344
04-18 11:39:11.303: I/dalvikvm(979):   | state=R schedstat=( 2590000000 85040000000 791 ) utm=236 stm=23 core=0
04-18 11:39:11.303: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:~94)
04-18 11:39:11.303: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:162)
04-18 11:39:11.303: I/dalvikvm(979):   at java.lang.StringBuilder.append(StringBuilder.java:311)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.eo.a((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.dx.a((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.dx.a((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.dx.b((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.dq.a((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.dq.bh((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.em$1.run((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at com.google.android.gms.internal.en$1.run((null):-1)
04-18 11:39:11.313: I/dalvikvm(979):   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
04-18 11:39:11.313: I/dalvikvm(979):   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
04-18 11:39:11.313: I/dalvikvm(979):   at java.lang.Thread.run(Thread.java:841)
04-18 11:39:11.333: I/Choreographer(979): Skipped 83 frames!  The application may be doing too much work on its main thread.
04-18 11:39:11.393: W/dalvikvm(979): threadid=11: thread exiting with uncaught exception (group=0xb3a7eba8)
04-18 11:39:11.873: I/dalvikvm-heap(979): Clamp target GC heap from 32.746MB to 32.000MB
04-18 11:39:11.883: D/dalvikvm(979): GC_FOR_ALLOC freed 132K, 5% free 31357K/32768K, paused 426ms, total 426ms
04-18 11:39:11.903: I/Choreographer(979): Skipped 44 frames!  The application may be doing too much work on its main thread.
04-18 11:39:12.613: I/dalvikvm-heap(979): Clamp target GC heap from 32.793MB to 32.000MB
04-18 11:39:12.633: D/dalvikvm(979): GC_FOR_ALLOC freed 163K, 5% free 31405K/32768K, paused 488ms, total 489ms
04-18 11:39:13.013: I/dalvikvm-heap(979): Clamp target GC heap from 32.796MB to 32.000MB
04-18 11:39:13.013: D/dalvikvm(979): GC_FOR_ALLOC freed 12K, 5% free 31409K/32768K, paused 374ms, total 374ms
04-18 11:39:13.013: I/dalvikvm-heap(979): Forcing collection of SoftReferences for 2162-byte allocation
04-18 11:39:13.373: I/dalvikvm-heap(979): Clamp target GC heap from 32.796MB to 32.000MB
04-18 11:39:13.373: D/dalvikvm(979): GC_BEFORE_OOM freed <1K, 5% free 31409K/32768K, paused 354ms, total 355ms
04-18 11:39:13.373: E/dalvikvm-heap(979): Out of memory on a 2162-byte allocation.
04-18 11:39:13.373: I/dalvikvm(979): "AdWorker #1" prio=5 tid=11 RUNNABLE
04-18 11:39:13.373: I/dalvikvm(979):   | group="main" sCount=0 dsCount=0 obj=0xb48db908 self=0xb7ecf560
04-18 11:39:13.373: I/dalvikvm(979):   | sysTid=1015 nice=10 sched=0/0 cgrp=apps/bg_non_interactive handle=-1209206344
04-18 11:39:13.383: I/dalvikvm(979):   | state=R schedstat=( 3560000000 85730000000 847 ) utm=331 stm=25 core=0
04-18 11:39:13.383: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:~94)
04-18 11:39:13.383: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:124)
04-18 11:39:13.383: I/dalvikvm(979):   at java.lang.StringBuffer.append(StringBuffer.java:278)
04-18 11:39:13.383: I/dalvikvm(979):   at java.io.StringWriter.write(StringWriter.java:123)
04-18 11:39:13.383: I/dalvikvm(979):   at com.android.internal.util.FastPrintWriter.flushLocked(FastPrintWriter.java:358)
04-18 11:39:13.383: I/dalvikvm(979):   at com.android.internal.util.FastPrintWriter.flush(FastPrintWriter.java:387)
04-18 11:39:13.383: I/dalvikvm(979):   at android.util.Log.getStackTraceString(Log.java:335)
04-18 11:39:13.383: I/dalvikvm(979):   at android.util.Slog.e(Slog.java:77)
04-18 11:39:13.383: I/dalvikvm(979):   at com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java:80)
04-18 11:39:13.383: I/dalvikvm(979):   at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:693)
04-18 11:39:13.393: I/dalvikvm(979):   at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:690)
04-18 11:39:13.713: I/dalvikvm-heap(979): Clamp target GC heap from 32.799MB to 32.000MB
04-18 11:39:13.723: D/dalvikvm(979): GC_FOR_ALLOC freed 7K, 5% free 31412K/32768K, paused 327ms, total 327ms
04-18 11:39:13.723: I/dalvikvm-heap(979): Forcing collection of SoftReferences for 2164-byte allocation
04-18 11:39:14.063: I/dalvikvm-heap(979): Clamp target GC heap from 32.799MB to 32.000MB
04-18 11:39:14.063: D/dalvikvm(979): GC_BEFORE_OOM freed 0K, 5% free 31412K/32768K, paused 344ms, total 345ms
04-18 11:39:14.073: E/dalvikvm-heap(979): Out of memory on a 2164-byte allocation.
04-18 11:39:14.073: I/dalvikvm(979): "AdWorker #1" prio=5 tid=11 RUNNABLE
04-18 11:39:14.073: I/dalvikvm(979):   | group="main" sCount=0 dsCount=0 obj=0xb48db908 self=0xb7ecf560
04-18 11:39:14.073: I/dalvikvm(979):   | sysTid=1015 nice=10 sched=0/0 cgrp=apps/bg_non_interactive handle=-1209206344
04-18 11:39:14.073: I/dalvikvm(979):   | state=R schedstat=( 4210000000 85770000000 885 ) utm=395 stm=26 core=0
04-18 11:39:14.073: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:~94)
04-18 11:39:14.073: I/dalvikvm(979):   at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:124)
04-18 11:39:14.073: I/dalvikvm(979):   at java.lang.StringBuffer.append(StringBuffer.java:278)
04-18 11:39:14.073: I/dalvikvm(979):   at java.io.StringWriter.write(StringWriter.java:123)
04-18 11:39:14.073: I/dalvikvm(979):   at com.android.internal.util.FastPrintWriter.flushLocked(FastPrintWriter.java:358)
04-18 11:39:14.073: I/dalvikvm(979):   at com.android.internal.util.FastPrintWriter.flush(FastPrintWriter.java:387)
04-18 11:39:14.073: I/dalvikvm(979):   at android.util.Log.getStackTraceString(Log.java:335)
04-18 11:39:14.073: I/dalvikvm(979):   at android.util.Slog.e(Slog.java:77)
04-18 11:39:14.073: I/dalvikvm(979):   at com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java:88)
04-18 11:39:14.073: I/dalvikvm(979):   at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:693)
04-18 11:39:14.083: I/dalvikvm(979):   at java.lang.ThreadGroup.uncaughtException(ThreadGroup.java:690)
04-18 11:39:14.083: I/Process(979): Sending signal. PID: 979 SIG: 9

Answer 1

內存不足不是一個例外，而是一個錯誤——您的程序不太可能從中恢復的狀態。 錯誤不是異常，因此捕獲異常不起作用。

如果你真的想抓住它，使用OutOfMemoryError ：

try {
  expensiveMethod();
} catch (OutOfMemoryError e) {
  // ...
}

請注意，如果您發現了這一點，您的意思是“我知道如何處理內存不足的情況”。 這極不可能是真的。 您的程序已經處於不穩定狀態，任何進一步的分配都可能會觸發另一個 OOME。

有沒有辦法獲得更多內存[...]？

正確的解決方案是讓您的程序一次使用更少的資源。 例如，您可以將求解器的工作分成離散塊，並在工作變得太大時增量存儲（例如，通過將其寫入磁盤）。 稍后，當您想要最終解決方案時，將解析的塊加載回內存並組裝它們。

有沒有辦法 [...] 在內存滿之前停止求解器？

您可以監控應用程序的當前內存使用情況：

MemoryInfo mi = new MemoryInfo();
ActivityManager a = (ActivityManager)getSystemService(ACTIVITY_SERVICE);
a.getMemoryInfo(mi);

並在此基礎上采取一些行動。 但是一旦你真的內存不足，做任何有用的事情可能已經太晚了。