我有一个问题。我正在调用一个测试函数，它从Java导入函数中获取多个字节，然后将该数据作为short数组返回。目前我遇到一个问题，程序崩溃与间接引用。我的代码是这样的：
#define AR_LEN 8
JNIEXPORT jshortArray JNICALL Java_com_example_datafeed_DataFeed_decode
(JNIEnv *env, jobject obj) {
int out_size = 0;
int i, frame_count;
short *data; /* data stream */
int shutdown = 1;
jbyte *temp;
short data_btes = AR_LEN *2;
jshortArray j_out_data;
// This gets the java class references
jclass cls = (*env)->FindClass(env, "com/example/datafeed/DataFeed");
jmethodID getbytes = (*env)->GetMethodID(env, cls, "getBytes", "(I)[B");
jmethodID outputMethod = (*env)->GetMethodID(env, cls, "playData", "([S)V");
// Set up a return array
j_out_data = (*env)->NewShortArray(env, AR_LEN);
data = malloc(AR_LEN * 2 + 2);
while(shutdown != 0) {
__android_log_print(ANDROID_LOG_ERROR, "Native", "Calling Method %d", data_btes);
// Call the java method to return byte array
jbyteArray getbytes_ret = (*env)->CallObjectMethod(env, obj, getbytes, data_btes);
// check for returned data
__android_log_print(ANDROID_LOG_ERROR, "Native", "Returned %p %d", temp, getbytes_ret);
//Get the array elements. This line seems to crash
temp = (*env)->GetByteArrayElements(env, getbytes_ret, 0);
__android_log_print(ANDROID_LOG_ERROR, "Native", "Array Set");
memcpy(data, temp, data_btes);
__android_log_print(ANDROID_LOG_ERROR, "Native", "Memory Copied");
// Delete the referece to temp
(* env)->DeleteLocalRef(env,temp);
if(temp == NULL) {
shutdown = 0;
} else {
// Set the Array of shorts
(*env)->SetShortArrayRegion(env,j_out_data, 0, AR_LEN, data);
// Call the return method
(*env)->CallObjectMethod(env, obj, outputMethod, j_out_data);
}
}
(* env)->DeleteLocalRef(env,outputMethod);
(* env)->DeleteLocalRef(env,j_out_data);
}
当我运行此代码时，我得到了这个输出：
E/Native(18292): Calling Method 16
D/FEED(18292): getting 16 bytes
D/FEED(18292): returning 16 bytes
E/Native(18292): Returned
E/Native(18292): Array Set
E/Native(18292): Memory Copied
W/dalvikvm(18292): JNI WARNING: DeleteLocalRef(0x42e06ac0) failed to find entry
D/OUTPUT(18292): recieved 8 data
E/Native(18292): Calling Method 0x6ded7770 16
E/Native(18292): Returned
W/dalvikvm(18292): Invalid indirect reference 0x8 in decodeIndirectRef
I/dalvikvm(18292): "Thread-55890" prio=5 tid=11 RUNNABLE
I/dalvikvm(18292): | group="main" sCount=0 dsCount=0 obj=0x42e06520 self=0x75221628
I/dalvikvm(18292): | sysTid=18308 nice=0 sched=0/0 cgrp=apps handle=1965187080
I/dalvikvm(18292): | state=R schedstat=( 0 0 0 ) utm=0 stm=0 core=0
I/dalvikvm(18292): at com.example.datafeed.DataFeed.decode(Native Method)
I/dalvikvm(18292): at com.example.datafeed.DataFeed.run(DataFeed.java:68)
I/dalvikvm(18292): at java.lang.Thread.run(Thread.java:841)
E/dalvikvm(18292): VM aborting
A/libc(18292): Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1), thread 18308 (Thread-55890)
I/DEBUG(17442): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG(17442): Build fingerprint: 'samsung/jfltexx/jflte:4.3/JSS15J/I9505XXUEMK9:user/release-keys'
I/DEBUG(17442): Revision: '11'
I/DEBUG(17442): pid: 18292, tid: 18308, name: Thread-55890 >>> com.example.datafeed <<<
I/DEBUG(17442): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadd00d
I/DEBUG(17442): r0 00000000 r1 00000000 r2 00000000 r3 40b76e50
I/DEBUG(17442): r4 deadd00d r5 0000020c r6 752342dc r7 752342e3
I/DEBUG(17442): r8 75336b38 r9 75225fb8 sl 75221638 fp 75336b4c
I/DEBUG(17442): ip 47844001 sp 753368b8 lr 00000001 pc 40afd970 cpsr 60000030
01-17 10:57:55.342: I/DEBUG(17442): d0 0000000000000000 d1 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d2 0000000000000000 d3 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d4 0010010200000010 d5 000000010000009c
01-17 10:57:55.342: I/DEBUG(17442): d6 ffffffffffffffff d7 3f8000003f800000
01-17 10:57:55.342: I/DEBUG(17442): d8 0000000000000000 d9 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d10 0000000000000000 d11 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d12 0000000000000000 d13 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d14 0000000000000000 d15 0000000000000000
01-17 10:57:55.342: I/DEBUG(17442): d16 6e616c2e6176616a d17 6461657268542e67
01-17 10:57:55.342: I/DEBUG(17442): d18 002e006300650073 d19 00700069006c0063
01-17 10:57:55.342: I/DEBUG(17442): d20 00720061006f0062 d21 00430049002e0064
01-17 10:57:55.342: I/DEBUG(17442): d22 006200700069006c d23 006400720061006f
01-17 10:57:55.342: I/DEBUG(17442): d24 ff00550055005500 d25 ff00550055005500
01-17 10:57:55.342: I/DEBUG(17442): d26 ff00550055005500 d27 ff00550055005500
01-17 10:57:55.342: I/DEBUG(17442): d28 ff00550055005500 d29 ff00550055005500
01-17 10:57:55.342: I/DEBUG(17442): d30 0000000d000d000d d31 0000000d000d000d
01-17 10:57:55.352: I/DEBUG(17442): scr 60000010
01-17 10:57:55.352: I/DEBUG(17442): backtrace:
01-17 10:57:55.352: I/DEBUG(17442): #00 pc 00048970 /system/lib/libdvm.so (dvmAbort+67)
01-17 10:57:55.352: I/DEBUG(17442): #01 pc 0004d41b /system/lib/libdvm.so (dvmDecodeIndirectRef(Thread*, _jobject*)+146)
01-17 10:57:55.352: I/DEBUG(17442): #02 pc 0004e141 /system/lib/libdvm.so
01-17 10:57:55.352: I/DEBUG(17442): #03 pc 00000cf3 /data/app-lib/com.example.datafeed-1/libdatafeed.so (Java_com_example_datafeed_DataFeed_decode+194)
01-17 10:57:55.352: I/DEBUG(17442): #04 pc 0002048c /system/lib/libdvm.so (dvmPlatformInvoke+112)
01-17 10:57:55.352: I/DEBUG(17442): #05 pc 00050ff3 /system/lib/libdvm.so (dvmCallJNIMethod(unsigned int const*, JValue*, Method const*, Thread*)+398)
01-17 10:57:55.352: I/DEBUG(17442): #06 pc 00052ca9 /system/lib/libdvm.so (dvmResolveNativeMethod(unsigned int const*, JValue*, Method const*, Thread*)+256)
01-17 10:57:55.352: I/DEBUG(17442): #07 pc 00029920 /system/lib/libdvm.so
01-17 10:57:55.352: I/DEBUG(17442): #08 pc 0002e2ec /system/lib/libdvm.so (dvmInterpret(Thread*, Method const*, JValue*)+184)
01-17 10:57:55.352: I/DEBUG(17442): #09 pc 00063179 /system/lib/libdvm.so (dvmCallMethodV(Thread*, Method const*, Object*, bool, JValue*, std::__va_list)+292)
01-17 10:57:55.352: I/DEBUG(17442): #10 pc 000631a3 /system/lib/libdvm.so (dvmCallMethod(Thread*, Method const*, Object*, JValue*, ...)+20)
01-17 10:57:55.352: I/DEBUG(17442): #11 pc 00057f03 /system/lib/libdvm.so
01-17 10:57:55.352: I/DEBUG(17442): #12 pc 0000cc60 /system/lib/libc.so (__thread_entry+72)
01-17 10:57:55.352: I/DEBUG(17442): #13 pc 0000cddc /system/lib/libc.so (pthread_create+208)
我注意到java方法只被调用一次，尽管CallObjectMethod被调用两次（它打印返回的输出，尽管没有从java代码打印调试方法）。不知道如何解决这个问题，我是否需要重置参考时间？如果有人有任何建议将不胜感激。
编辑：不确定这是否有帮助，但我添加了java代码。
public class DataFeed {
static {
System.loadLibrary("datafeed");
}
private BlockingQueue<Byte> inputQueue;
public DataFeed () {
inputQueue=new LinkedBlockingQueue<Byte>();
}
public native void decode();
public byte[] getBytes (int bytes) {
int curbyte = 0;
byte[] retbytes = new byte[bytes];
Log.d("FEED", "getting " + bytes + " bytes");
while(curbyte < bytes) {
try {
retbytes[curbyte] = inputQueue.take();
} catch (InterruptedException e) {
e.printStackTrace();
return null;
}
curbyte ++;
}
Log.d("FEED", "returning " + retbytes.length + " bytes ");
return retbytes;
}
public void playData(short[] outdata) {
Log.d("OUTPUT", "recieved " + outdata.length + " data");
}
}
答案 0 :(得分：2)
调用GetByteArrayElements时，您应释放ReleaseByteArrayElements而不是DeleteLocalRef的指针。例如：
int fLen = env->GetArrayLength(getbytes_ret);
jbyte *temp = (jbyte *)(*env)->GetByteArrayElements(env, getbytes_ret, NULL);
__android_log_print(ANDROID_LOG_ERROR, "Native", "Array Set");
memcpy(data, temp, fLen );
__android_log_print(ANDROID_LOG_ERROR, "Native", "Memory Copied");
(*env)->ReleaseByteArrayElements(env, getbytes_ret, temp, 0 );