{"id":2521,"date":"2023-07-06T12:04:16","date_gmt":"2023-07-06T04:04:16","guid":{"rendered":"https:\/\/www.zhidianwl.com\/zhidian\/?p=2521"},"modified":"2023-07-06T12:04:16","modified_gmt":"2023-07-06T04:04:16","slug":"android-jni%e5%bc%80%e5%8f%91%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.zhidianwl.com\/zhidian\/2023\/2521\/","title":{"rendered":"android jni\u5f00\u53d1\u662f\u4ec0\u4e48\u610f\u601d\uff1f"},"content":{"rendered":"

JNI\uff08Java Native Interface\uff09\u662fJava\u4e0e\u672c\u5730\u4ee3\u7801\u4ea4\u4e92\u7684\u4e00\u79cd\u673a\u5236\u3002\u5728Android\u5f00\u53d1\u4e2d\uff0cJNI\u88ab\u5e7f\u6cdb\u5e94\u7528\u4e8eJava\u4ee3\u7801\u4e0eC\/C++\u4ee3\u7801\u4e4b\u95f4\u7684\u4ea4\u4e92\u3002<\/p>\n

JNI\u7684\u5de5\u4f5c\u539f\u7406<\/p>\n

JNI\u7684\u5de5\u4f5c\u539f\u7406\u662f\u901a\u8fc7Java\u865a\u62df\u673a\uff08JVM\uff09\u63d0\u4f9b\u7684JNI\u63a5\u53e3\uff0c\u5c06Java\u4ee3\u7801\u4e0e\u672c\u5730\u4ee3\u7801\uff08\u5982C\/C++\uff09\u8fde\u63a5\u8d77\u6765\u3002\u8fd9\u6837\uff0c\u5728Java\u4ee3\u7801\u4e2d\u5c31\u53ef\u4ee5\u8c03\u7528\u672c\u5730\u4ee3\u7801\u4e2d\u7684\u51fd\u6570\uff0c\u4e5f\u53ef\u4ee5\u5c06Java\u5bf9\u8c61\u4f20\u9012\u7ed9\u672c\u5730\u4ee3\u7801\u4e2d\u4f7f\u7528\uff0c\u672c\u5730\u4ee3\u7801\u4e5f\u53ef\u4ee5\u5c06\u6570\u636e\u8fd4\u56de\u7ed9Java\u4ee3\u7801\u3002<\/p>\n

JNI\u7684\u4f7f\u7528\u6b65\u9aa4<\/p>\n

1.\u7f16\u5199\u672c\u5730\u4ee3\u7801<\/p>\n

\u5728\u672c\u5730\u4ee3\u7801\u4e2d\uff0c\u901a\u8fc7JNI\u63d0\u4f9b\u7684\u63a5\u53e3\u4e0eJava\u4ee3\u7801\u4ea4\u4e92\u3002\u672c\u5730\u4ee3\u7801\u9700\u8981\u4f7f\u7528C\/C++\u8bed\u8a00\u7f16\u5199\uff0c\u5e76\u4e14\u9700\u8981\u5305\u542bjni.h\u5934\u6587\u4ef6\uff0c\u8be5\u5934\u6587\u4ef6\u4e2d\u5b9a\u4e49\u4e86\u4e0eJava\u4ee3\u7801\u4ea4\u4e92\u6240\u9700\u7684\u51fd\u6570\u548c\u6570\u636e\u7c7b\u578b\u3002<\/p>\n

2.\u751f\u6210\u52a8\u6001\u94fe\u63a5\u5e93<\/p>\n

\u5c06\u672c\u5730\u4ee3\u7801\u7f16\u8bd1\u6210\u52a8\u6001\u94fe\u63a5\u5e93\uff08.so\u6587\u4ef6\uff09\uff0c\u5728Android\u4e2d\u53ef\u4ee5\u4f7f\u7528ndk-build\u547d\u4ee4\u6765\u7f16\u8bd1\u751f\u6210\u52a8\u6001\u94fe\u63a5\u5e93\u3002<\/p>\n

3.\u5728Java\u4ee3\u7801\u4e2d\u4f7f\u7528JNI<\/p>\n

\u5728Java\u4ee3\u7801\u4e2d\uff0c\u4f7f\u7528System.loadLibrary()\u65b9\u6cd5\u52a0\u8f7d\u52a8\u6001\u94fe\u63a5\u5e93\uff0c\u7136\u540e\u901a\u8fc7JNI\u63a5\u53e3\u8c03\u7528\u672c\u5730\u4ee3\u7801\u4e2d\u7684\u51fd\u6570\u3002<\/p>\n

JNI\u7684\u6570\u636e\u7c7b\u578b<\/p>\n

JNI\u652f\u6301Java\u4e0e\u672c\u5730\u4ee3\u7801\u4e4b\u95f4\u7684\u6570\u636e\u8f6c\u6362\uff0c\u4ee5\u4e0b\u662fJava\u6570\u636e\u7c7b\u578b\u4e0eJNI\u6570\u636e\u7c7b\u578b\u7684\u5bf9\u5e94\u5173\u7cfb\uff1a<\/p>\n

Java\u7c7b\u578b | JNI\u7c7b\u578b<\/p>\n

——– | ——<\/p>\n

boolean | jboolean<\/p>\n

byte | jbyte<\/p>\n

char | jchar<\/p>\n

short | jshort<\/p>\n

int | jint<\/p>\n

long | jlong<\/p>\n

float | jfloat<\/p>\n

double | jdouble<\/p>\n

Object | jobandroid_source<\/a>ject<\/p>\n

String | jstring<\/p>\n

Array | jarray<\/p>\n

JNI\u7684\u5e38\u7528\u51fd\u6570<\/p>\n

1.\u83b7\u53d6JNIEnv\u6307\u9488<\/p>\n

JNIEnv\u662fJNI\u63d0\u4f9b\u7684\u63a5\u53e3\uff0c\u53ef\u4ee5\u5728\u672c\u5730\u4ee3\u7801\u4e2d\u4f7f\u7528JNIEnv\u6307\u9488\u4e0eJava\u4ee3\u7801\u4ea4\u4e92\u3002\u83b7\u53d6JNIEnv\u6307\u9488\u7684\u65b9\u5f0f\u5982\u4e0b\uff1a<\/p>\n

“`<\/p>\n

void JNICALL Java_com_example_MyClass\u79fb\u52a8\u7aef\u6253\u5305\u6210app<\/a>_nativeMethod(JNIEnv *env, jobject obj) {<\/p>\n

\/\/ TODO: \u5728\u8fd9\u91cc\u4f7f\u7528JNIEnv\u6307\u9488\u4e0eJava\u4ee3\u7801\u4ea4\u4e92<\/p>\n

}<\/p>\n

“`<\/p>\n

2.\u8c03\u7528Java\u65b9\u6cd5<\/p>\n

\u5728\u672c\u5730\u4ee3\u7801\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528JNIEnv\u6307\u9488\u8c03\u7528Java\u4ee3\u7801\u4e2d\u7684\u65b9\u6cd5\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n

“`<\/p>\n

jclass cls = (*env)->GetObjectClass(env, obj); \/\/ \u83b7\u53d6Java\u5bf9\u8c61\u7684\u7c7b<\/p>\n

jmethodID mid = (*env)->GetMethodID(env, cls, “method”, “()V”); \/\/ \u83b7\u53d6Java\u65b9\u6cd5\u7684ID<\/p>\n

(*env)->CallVoidMethod(env, obj, mid); \/\/ \u8c03\u7528Java\u65b9\u6cd5<\/p>\n

“`<\/p>\n

3.\u83b7\u53d6Java\u53d8\u91cf\u503c<\/p>\n

\u5728\u672c\u5730\u4ee3\u7801\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528JNIEnv\u6307\u9488\u83b7\u53d6Java\u5bf9\u8c61\u7684\u53d8\u91cf\u503c\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n

“`<\/p>\n

jclass cls = (*env)->GetObjectClass(env, obj); \/\/ \u83b7\u53d6Java\u5bf9\u8c61\u7684\u7c7b<\/p>\n

jfieldID fid = (*env)->GetFieldID(env, cls, “field”, “Ljava\/lang\/String;”); \/\/ \u83b7\u53d6Java\u53d8\u91cf\u7684ID<\/p>\n

jstring str = (*env)->GetObjectField(env, obj, fid); \/\/ \u83b7\u53d6Java\u5b57\u7b26\u4e32\u53d8\u91cf\u7684\u503c<\/p>\n

“`<\/p>\n

4.\u8bbe\u7f6eJava\u53d8\u91cf\u503c<\/p>\n

\u5728\u672c\u5730\u4ee3\u7801\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528JNIEnv\u6307\u9488\u8bbe\u7f6eJava\u5bf9\u8c61\u7684\u53d8\u91cf\u503c\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n

“`<\/p>\n

jclass cls = (*env)->GetObjectClass(env, obj); \/\/ \u83b7\u53d6Java\u5bf9\u8c61\u7684\u7c7b<\/p>\n

jfieldID fid =<\/p>\n

<\/figure>\n<\/p>\n

(*env)->GetFieldID(env, cls, “field”, “Ljava\/lang\/String;”); \/\/ \u83b7\u53d6Java\u53d8\u91cf\u7684ID<\/p>\n

jstring str = (*env)->NewStringUTF(env, “Hello, JNI!”); \/\/ \u521b\u5efaJava\u5b57\u7b26\u4e32\u5bf9\u8c61<\/p>\n

(*env)->SetObjectField(env, obj, fid, str); \/\/ \u8bbe\u7f6eJava\u5b57\u7b26\u4e32\u53d8\u91cf\u7684\u503c<\/p>\n

“`<\/p>\n

\u603b\u7ed3<\/p>\n

JNI\u662fJava\u4e0e\u672c\u5730\u4ee3\u7801\u4ea4\u4e92\u7684\u4e00\u79cd\u673a\u5236\uff0c\u53ef\u4ee5\u5728Android\u5f00\u53d1\u4e2d\u5b9e\u73b0Java\u4ee3\u7801\u4e0eC\/C++\u4ee3\u7801\u4e4b\u95f4\u7684\u4ea4\u4e92\u3002\u4f7f\u7528JNI\u9700\u8981\u7f16\u5199\u672c\u5730\u4ee3\u7801\uff0c\u5e76\u5c06\u5176\u7f16\u8bd1\u6210\u52a8\u6001\u94fe\u63a5\u5e93\uff0c\u5728Java\u4ee3\u7801\u4e2d\u4f7f\u7528System.loadLibrary()\u65b9\u6cd5\u52a0\u8f7d\u52a8\u6001\u94fe\u63a5\u5e93\uff0c\u7136\u540e\u901a\u8fc7JNI\u63a5\u53e3\u8c03\u7528\u672c\u5730\u4ee3\u7801\u4e2d\u7684\u51fd\u6570\u3002JNI\u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u51fd\u6570\u548c\u6570\u636e\u7c7b\u578b\uff0c\u53ef\u4ee5\u5b9e\u73b0Java\u4e0e\u672c\u5730\u4ee3\u7801\u4e4b\u95f4\u7684\u6570\u636e\u8f6c\u6362\u548c\u4ea4\u4e92\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

JNI\uff08Java Native Interface\uff09\u662fJava\u4e0e\u672c\u5730\u4ee3\u7801\u4ea4\u4e92\u7684\u4e00\u79cd\u673a\u5236\u3002\u5728Android\u5f00\u53d1\u4e2d\uff0cJNI\u88ab\u5e7f\u6cdb\u5e94\u7528\u4e8eJava\u4ee3\u7801\u4e0eC\/C++\u4ee3\u7801\u4e4b\u95f4\u7684\u4ea4\u4e92\u3002JNI\u7684\u5de5\u4f5c\u539f\u7406JNI\u7684\u5de5\u4f5c<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[5214,5212,81,596,5213],"class_list":["post-2521","post","type-post","status-publish","format-standard","hentry","category-zuoapp","tag-apkios","tag-ios","tag-81","tag-596","tag-5213"],"_links":{"self":[{"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/posts\/2521","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/comments?post=2521"}],"version-history":[{"count":0,"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/posts\/2521\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/media?parent=2521"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/categories?post=2521"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zhidianwl.com\/zhidian\/wp-json\/wp\/v2\/tags?post=2521"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}