Android Studio2.2 配置NDK

Android Studio2.2 配置NDK。

环境

 主机:WIN10
开发环境:Android Studio2.2 Preview 3

步骤

安装NDK
打开Tools->Android->SDK Manager->SDK Tools选中LLDB和NDK，点击确认，软件会自动安装NDK。

配置环境变量

增加一项：NDK_ROOT，如：C:\soft\adt-bundle-windows-x86-20130911\sdk\ndk-bundle
在path中增加%NDK_ROOT%

在main中新建文件夹jni

新建hello-jni.c
函数需按照规则命名：Java_包名类名方法名

/*
 * Copyright (C) 2009 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 
#include 

/* 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:
 *
 *   apps/samples/hello-jni/project/src/com/example/hellojni/HelloJni.java
 */
//jstring
//Java_com_bazhangkeji_MainActivity_stringFromJNI( JNIEnv* env,
//                                                  jobject thiz )
//{
//    return (*env)->NewStringUTF(env, "Hello from JNI !");
//}

JNIEXPORT jstring JNICALL
Java_com_bazhangkeji_demo01_MainActivity_stringFromJNI(JNIEnv *env, jobject instance) {

//    // TODO
//
//
//    return (*env)->NewStringUTF(env, returnValue);
    return (*env)->NewStringUTF(env, "Hello from JNI !");
}

新建Android.mk

# Copyright (C) 2009 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.
#
LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := hello-jni
LOCAL_SRC_FILES := hello-jni.c

include $(BUILD_SHARED_LIBRARY)

在build.gradle中配置
配置好，make project即可生成.so文件在app\build\intermediates\ndk-build\debug\lib中。
增加语句：

externalNativeBuild {
        ndkBuild {
            path file("src\\main\\jni\\Android.mk")
        }
    }

 

完整的代码：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.0"
    defaultConfig {
        applicationId "com.bazhangkeji.demo01"
        minSdkVersion 15
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

//        ndk {
//            moduleName "libspeex"
//            cFlags "-std=c++11 -fexceptions"
//            ldLibs "log"
//            stl "gnustl_shared"
//            abiFilter "armeabi-v7a"
//        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    externalNativeBuild {
        ndkBuild {
            path file("src\\main\\jni\\Android.mk")
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:24.0.0'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha3'
    compile 'com.android.support:design:24.0.0'
    testCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.2'
    androidTestCompile 'com.android.support.test:runner:0.5'
    androidTestCompile 'com.androd.support:support-annotations:24.0.0'
}

在java层调用

public class MainActivity extends AppCompatActivity {

    private static final int RECORDER_SAMPLERATE = 8000;
    private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
    private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
    private AudioRecord recorder = null;
    private Thread recordingThread = null;
    private boolean isRecording = false;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        setButtonHandlers();
        enableButtons(false);
        int bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,
                RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING);

        System.out.println(stringFromJNI());
    }
    public native String stringFromJNI();
    public native String unimplementedStringFromJNI();
    static {
        System.loadLibrary("hello-jni");
    }