安卓 Jni : crash in global and local ref variables

Question

我有调用 java 对象方法的 jni c++ 代码，示例:

jclass JIOManager = CJavaEnv::getInstance()->env()->FindClass(ioManagerName);

    ..... some code

CJavaEnv::getInstance()->env()->DeleteLocalRef(JIOManager);

这在主线程中执行时效果很好，但是当我尝试在另一个线程中执行时它崩溃是因为它说它是在另一个线程中创建的:O!但在我阅读 google android 开发者网站后，他们说从任何线程访问 Global Ref 都可以，所以我将该代码更改为类似。

jclass JIOManager = (jclass)CJavaEnv::getInstance()->env()->NewGlobalRef( CJavaEnv::getInstance()->env()->FindClass(ioManagerName) );

    ..... some code

CJavaEnv::getInstance()->env()->DeleteGlobalRef(JIOManager);

但我遇到了这个崩溃:

09-21 15:38:13.259: E/dalvikvm(3210): JNI ERROR (app bug): local reference table overflow (max=512)
09-21 15:38:13.259: W/dalvikvm(3210): JNI local reference table (0x76fb50) dump:
09-21 15:38:13.259: W/dalvikvm(3210):   Last 10 entries (of 512):
09-21 15:38:13.259: W/dalvikvm(3210):       511: 0x40a609a8 java.lang.Class<libcore.icu.NativeConverter>
09-21 15:38:13.259: W/dalvikvm(3210):       510: 0x42349610 byte[] (1 elements)
09-21 15:38:13.259: W/dalvikvm(3210):       509: 0x41d866b8 java.lang.Class<com.Cocoa.CocoaAndroidSDK.CocoaUnicodeConverter>
09-21 15:38:13.259: W/dalvikvm(3210):       508: 0x423495f8 byte[] (2 elements)
09-21 15:38:13.259: W/dalvikvm(3210):       507: 0x42349428 byte[] (1 elements)
09-21 15:38:13.259: W/dalvikvm(3210):       506: 0x41d866b8 java.lang.Class<com.Cocoa.CocoaAndroidSDK.CocoaUnicodeConverter>
09-21 15:38:13.259: W/dalvikvm(3210):       505: 0x42349410 byte[] (2 elements)
09-21 15:38:13.259: W/dalvikvm(3210):       504: 0x422b3f08 byte[] (1 elements)
09-21 15:38:13.259: W/dalvikvm(3210):       503: 0x41d866b8 java.lang.Class<com.Cocoa.CocoaAndroidSDK.CocoaUnicodeConverter>
09-21 15:38:13.259: W/dalvikvm(3210):       502: 0x422b3ef0 byte[] (2 elements)
09-21 15:38:13.259: W/dalvikvm(3210):   Summary:
09-21 15:38:13.259: W/dalvikvm(3210):       172 of java.lang.Class (3 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         1 of java.lang.String
09-21 15:38:13.259: W/dalvikvm(3210):         8 of byte[] (8 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        20 of byte[] (1 elements) (20 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        27 of byte[] (2 elements) (27 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         2 of byte[] (3 elements) (2 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        16 of byte[] (4 elements) (16 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        40 of byte[] (5 elements) (40 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         2 of byte[] (6 elements) (2 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         4 of byte[] (7 elements) (4 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        22 of byte[] (8 elements) (22 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        15 of byte[] (9 elements) (15 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        40 of byte[] (10 elements) (40 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         3 of byte[] (11 elements) (3 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        17 of byte[] (12 elements) (17 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         7 of byte[] (14 elements) (7 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         8 of byte[] (15 elements) (8 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        15 of byte[] (16 elements) (15 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         8 of byte[] (17 elements) (8 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        16 of byte[] (18 elements) (16 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         3 of byte[] (21 elements) (3 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         3 of byte[] (22 elements) (3 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):        17 of byte[] (24 elements) (17 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         4 of byte[] (28 elements) (4 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         8 of byte[] (30 elements) (8 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         1 of byte[] (32 elements)
09-21 15:38:13.259: W/dalvikvm(3210):         4 of byte[] (33 elements) (4 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         8 of byte[] (34 elements) (8 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         5 of byte[] (36 elements) (5 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         2 of byte[] (41 elements) (2 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         3 of byte[] (42 elements) (3 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         1 of byte[] (56 elements)
09-21 15:38:13.259: W/dalvikvm(3210):         4 of byte[] (66 elements) (4 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         4 of byte[] (72 elements) (4 unique instances)
09-21 15:38:13.259: W/dalvikvm(3210):         2 of byte[] (82 elements) (2 unique instances)
09-21 15:38:13.259: E/dalvikvm(3210): Failed adding to JNI local ref table (has 512 entries)
09-21 15:38:13.259: I/dalvikvm(3210): "AsyncTask #2" prio=5 tid=16 RUNNABLE
09-21 15:38:13.259: I/dalvikvm(3210):   | group="main" sCount=0 dsCount=0 obj=0x41decfd8 self=0x776200
09-21 15:38:13.259: I/dalvikvm(3210):   | sysTid=3236 nice=10 sched=0/0 cgrp=bg_non_interactive handle=7541280
09-21 15:38:13.259: I/dalvikvm(3210):   | schedstat=( 0 0 0 ) utm=82 stm=70 core=1
09-21 15:38:13.259: I/dalvikvm(3210):   at libcore.icu.NativeConverter.openConverter(Native Method)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.nio.charset.CharsetEncoderICU.newInstance(CharsetEncoderICU.java:71)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.nio.charset.CharsetICU.newEncoder(CharsetICU.java:27)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.nio.charset.Charset.encode(Charset.java:451)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.lang.String.getBytes(String.java:870)
09-21 15:38:13.259: I/dalvikvm(3210):   at com.Cocoa.CocoaAndroidSDK.CocoaUnicodeConverter.UTF8_TO_UTF16(CocoaUnicodeConverter.java:16)
09-21 15:38:13.259: I/dalvikvm(3210):   at com.Cocoa.CocoaAndroidSDK.CocoaSDKNativeLib.load(Native Method)
09-21 15:38:13.259: I/dalvikvm(3210):   at com.Cocoa.CocoaViewer.MainActivity$LongOperation.doInBackground(MainActivity.java:1498)
09-21 15:38:13.259: I/dalvikvm(3210):   at com.Cocoa.CocoaViewer.MainActivity$LongOperation.doInBackground(MainActivity.java:1)
09-21 15:38:13.259: I/dalvikvm(3210):   at android.os.AsyncTask$2.call(AsyncTask.java:264)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
09-21 15:38:13.259: I/dalvikvm(3210):   at java.lang.Thread.run(Thread.java:856)
09-21 15:38:13.259: E/dalvikvm(3210): VM aborting
09-21 15:38:13.259: A/libc(3210): Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1)

感谢任何帮助。

Answer 1

还必须附加“其他”线程才能使用 JIOManager。为什么不在那里也获得本地引用资料？另一方面，您的崩溃转储表明您实际上只查看了 3 个类。因此，您可以一次创建对它们的全局引用(如果您觉得更容易，甚至可以在 JNI_OnLoad() 中创建)，并在所有 native 线程中使用它们。