1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #include<unistd.h>
 4 #include<pthread.h>
 5 
 6 #include<jni.h>
 7 #include<android/log.h>
 8 
 9 #define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "native-activity", __VA_ARGS__))
10 #define LOGW(...) ((void)__android_log_print(ANDROID_LOG_WARN, "native-activity", __VA_ARGS__))
11
 
 #define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, "native-activity", __VA_ARGS__))
12 
13 //執行緒數14 #define NUMTHREADS 5
15 
16 //全域性變數17 JavaVM *g_jvm = NULL;
18 jobject g_obj = NULL;
19 
20 
21 void *thread_fun(void* arg)
22 {
23     JNIEnv *env;
24     jclass cls;
25     jmethodID mid;
26 
27     //Attach主執行緒
 
28     if((*g_jvm)->AttachCurrentThread(g_jvm, &env, NULL) != JNI_OK)
29     {
30         LOGE("%s: AttachCurrentThread() failed", __FUNCTION__);
31         return NULL;
32     }
33     //找到對應的類34     cls = (*env)->GetObjectClass(env,g_obj);
35     if(cls == NULL)
36     {
37         LOGE("FindClass() Error.....
 
");
38         goto error; 
39     }
40     //再獲得類中的方法41     mid = (*env)->GetStaticMethodID(env, cls, "fromJNI", "(I)V");
42     if (mid == NULL) 
43     {
44         LOGE("GetMethodID() Error.....");
45         goto error;  
46     }
47     //最後呼叫java中的靜態方法48         (*env)->CallStaticVoidMethod(env, cls, mid ,(int)arg);
49     
50 
51 error:    
52     //Detach主執行緒53     if((*g_jvm)->DetachCurrentThread(g_jvm) != JNI_OK)
54     {
55         LOGE("%s: DetachCurrentThread() failed", __FUNCTION__);
56     }
57     
58 
59     pthread_exit(0);
60 }
61 
62 //由java呼叫以建立子執行緒63 JNIEXPORT void Java_com_nan_thread_MyThreadActivity_mainThread( JNIEnv* env, jobject obj)
64 {
65     int i;
66     pthread_t pt[NUMTHREADS];
67     
68     for (i = 0; i < NUMTHREADS; i++)
69         //建立子執行緒70         pthread_create(&pt[i], NULL, &thread_fun, (void *)i);
71 }
72 
73 
74 //由java呼叫來建立JNI環境75 JNIEXPORT void Java_com_nan_thread_MyThreadActivity_setJNIEnv( JNIEnv* env, jobject obj)
76 {
77     //儲存全域性JVM以便在子執行緒中使用78     (*env)->GetJavaVM(env,&g_jvm);
79     //不能直接賦值(g_obj = obj)80     g_obj = (*env)->NewGlobalRef(env,obj);
81 }
82 
83 
84 //當動態庫被載入時這個函式被系統呼叫85 JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved)
86 {
87     JNIEnv* env = NULL;
88     jint result = -1;    
89 
90     //獲取JNI版本91     if ((*vm)->GetEnv(vm, (void**)&env, JNI_VERSION_1_4) != JNI_OK) 
92     {
93         LOGE("GetEnv failed!");
94             return result;
95     }
96 
97     return JNI_VERSION_1_4;
98 }