Android Studio下Java Jni技术 _Android

书史足自悦，安用勤与劬。这篇文章主要讲述Android Studio下Java Jni技术相关的知识，希望能为你提供帮助。
最近开发android的过程中需要通过C来调用Android终端中的某些API，而我是用java语言来开发的Android程序，所以就需要用到JNI调用。

流程是，用C来调用Android硬件接口，约定JAVA调用C的接口，然后把这些代码封装编译成.so文件。然后就是怎么引入与调用了。

1、将.so文件加入到libs目录下，.so文件命名规范为lib*，lib后加上名字。
2、加入jniLibs路径配置，在build.gradle中加入如下配置：

android { …… sourceSets { main { jniLibs.srcDirs = [‘libs‘] } } }

3、JAVA调用

public class UspJni { private final static String TAG = "USPJNI"; static { try{ System.loadLibrary("uspjni"); //加载libuspjni.so Log.d(TAG, "libuspjni.so load"); }catch(Exception e){ System.err.println("Native code library failed to load.\n"+e); } } public static UspJni getInstance() { if (jni == null) { jni = new UspJni(); } return jni; } public int uartOpen(String path, int flags) { Log.d(TAG, "(uartOpen)path=" + path + ",flags=" + String.valueOf(flags)); uartFd = this.open(path, flags); if (uartFd < 0) { Log.d(TAG, "(uartOpen)failed" + ",uartFd=" + String.valueOf(uartFd)); } return uartFd; } public int uartClose() { Log.d(TAG, "(uartClose)"); int status = this.close(uartFd); uartFd = -1; if (status != 0) { Log.d(TAG, "(uartClose)failed,status=" + String.valueOf(status) + ",uartFd=" + uartFd); } return status; } public byte[] uartRead(int timeout) { Log.d(TAG, "(uartRead)timeout=" + timeout); byte[] buff = this.read(uartFd,timeout); if (buff==null) { return new byte[0]; } Log.d(TAG, "(uartRead)len=" + buff.length); return buff; } public int uartFlush() { Log.d(TAG, "(uartFlush)"); byte[] data; do { data = UspJni.getInstance().uartRead(50); //调用 }while(data.length> 0); return 0; } public native int gpiosetStatus(int ioId, int status); public native int gpioGetStatus(int ioId); private native int open(String path, int flags); private native int close(int fd); private native byte[] read(int fd,int timeout); private native int write(int fd, byte[] data, int count); private static UspJni jni; private UspJni() { } }

【Android Studio下Java Jni技术】本文出自 “雪飘七月” 博客，请务必保留此出处http://xuepiaoqiyue.blog.51cto.com/4391594/1884139