Android JNI编程-优快云博客

本文详细介绍了如何通过Java与JNI（Java Native Interface）结合，在Android应用中实现跨平台调用的方法，包括创建工程、生成头文件、C文件以及Android.mk文件的步骤，并最终生成.so库，演示了如何在Android环境中调用C/C++代码。

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创建工程:结构如下

代码如下：

package com.tcl.testjni;

public class MyJNI {

public native void fun();
}

package com.tcl.testjni;

import android.R.integer;
import android.app.Activity;
import android.os.Bundle;
import android.text.StaticLayout;

public class TestJNIActivity extends Activity {
	static{
		System.loadLibrary("kang");
	}
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       MyJNI jni = new MyJNI();
       jni.fun();

    }
}

这样在工程的bin目录下就生成了.class文件，这时切换到src目录，用javah生成头文件:

根据头文件创建.c文件

/* DO NOT EDIT THIS FILE - it is machine generated */
#include "com_tcl_testjni_MyJNI.h"
JNIEXPORT void JNICALL Java_com_tcl_testjni_MyJNI_fun
  (JNIEnv *, jobject)
{
	printf("%s","here is jni");
}

创建 Android.mk文件

#
# Copyright (C) 2008 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_SRC_FILES:= \   
com_tcl_testjni_MyJNI.c  
 LOCAL_C_INCLUDES := \   
 $(JNI_H_INCLUDE)   
 LOCAL_SHARED_LIBRARIES := libutils   
 LOCAL_PRELINK_MODULE := false   
 LOCAL_MODULE := libkang  
 include $(BUILD_SHARED_LIBRARY)

将.h .c Android.mk文件放入一个文件夹，复制到Android源码 2.2source/external/XXX，然后编译下这个文件夹就会生成so库啦，将so放到工程的libs/armeabi下，再运行试试，可以了吧。