android官方hello-jni示例

android/app/build.gradle

@@ -162,6 +162,12 @@ android {
             proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
         }
     }
+    externalNativeBuild {
+        cmake {
+            version '3.10.2'
+            path "../../cpp/jni/CMakeLists.txt"
+        }
+    }
     // applicationVariants are e.g. debug, release
     applicationVariants.all { variant ->
         variant.outputs.each { output ->

android/app/src/main/java/com/example/jni/ToastModule.java

@@ -39,6 +39,13 @@ public Map<String, Object> getConstants() {
 
   @ReactMethod
   public void show(String message, int duration) {
+    message = message + " | " + stringFromJNI();
     Toast.makeText(getReactApplicationContext(), message, duration).show();
   }
+
+  public native String stringFromJNI();
+
+  static {
+      System.loadLibrary("hello-jni");
+  }
 }

cpp/jni/CMakeLists.txt

@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 3.4.1)
+
+add_library(hello-jni SHARED
+            hello-jni.c)
+
+# Include libraries needed for hello-jni lib
+target_link_libraries(hello-jni
+                      android
+                      log)

cpp/jni/hello-jni.c

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#include <string.h>
+#include <jni.h>
+
+/* This is a trivial JNI example where we use a native method
+ * to return a new VM String. See the corresponding Java source
+ * file located at:
+ *
+ *   hello-jni/app/src/main/java/com/example/hellojni/HelloJni.java
+ */
+JNIEXPORT jstring JNICALL
+Java_com_example_jni_ToastModule_stringFromJNI( JNIEnv* env,
+                                                  jobject thiz )
+{
+#if defined(__arm__)
+    #if defined(__ARM_ARCH_7A__)
+    #if defined(__ARM_NEON__)
+      #if defined(__ARM_PCS_VFP)
+        #define ABI "armeabi-v7a/NEON (hard-float)"
+      #else
+        #define ABI "armeabi-v7a/NEON"
+      #endif
+    #else
+      #if defined(__ARM_PCS_VFP)
+        #define ABI "armeabi-v7a (hard-float)"
+      #else
+        #define ABI "armeabi-v7a"
+      #endif
+    #endif
+  #else
+   #define ABI "armeabi"
+  #endif
+#elif defined(__i386__)
+#define ABI "x86"
+#elif defined(__x86_64__)
+#define ABI "x86_64"
+#elif defined(__mips64)  /* mips64el-* toolchain defines __mips__ too */
+#define ABI "mips64"
+#elif defined(__mips__)
+#define ABI "mips"
+#elif defined(__aarch64__)
+#define ABI "arm64-v8a"
+#else
+#define ABI "unknown"
+#endif
+
+    return (*env)->NewStringUTF(env, "Hello from JNI !  Compiled with ABI " ABI ".");
+}