android通过JNI控制GPIO

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少废话直接贴代码：

软件环境：android studio 2.2 ; NDK最好单独下载12r版本就可以； allwinner开发板

1、编写jni头文件及源文件

在main/java同级目录下创建jni文件夹用于存放.h,.c文件

.h文件如下：

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_example_beep_GpioCtr */

#ifndef _Included_com_example_beep_GpioCtr
#define _Included_com_example_beep_GpioCtr
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_example_beep_GpioCtr
 * Method:    exportGpio
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_exportGpio
        (JNIEnv *, jclass, jint);

/*
 * Class:     com_example_beep_GpioCtr
 * Method:    setGpioDirection
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_setGpioDirection
  (JNIEnv *, jclass, jint, jint);

/*
 * Class:     com_example_beep_GpioCtr
 * Method:    readGpioStatus
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_readGpioStatus
  (JNIEnv *, jclass, jint);

/*
 * Class:     com_example_beep_GpioCtr
 * Method:    writeGpioStatus
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_writeGpioStatus
  (JNIEnv *, jclass, jint, jint);

/*
 * Class:     com_example_beep_GpioCtr
 * Method:    unexportGpio
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_unexportGpio
  (JNIEnv *, jclass, jint);

#ifdef __cplusplus
}
#endif
#endif

.c文件如下：

//
// Created by Administrator on 2018/12/1.
//

#include <jni.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <android/log.h>

#include "com_example_beep_GpioCtr.h"

#define TAG "jni_gpio"
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG ,__VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG ,__VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,TAG ,__VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG ,__VA_ARGS__)
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,TAG ,__VA_ARGS__)

#define IN              0
#define OUT             1
#define LOW             0
#define HIGH            1

#define BUFFER_MAX    3
#define DIRECTION_MAX 48

/*
 * Class:     com_zhuang_jnigpio_GPIOControl
 * Method:    exportGpio
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_exportGpio(JNIEnv *env, jobject instance, jint gpio)
{
    char buffer[BUFFER_MAX];
    int len;
    int fd;

    fd = open("/sys/class/gpio/export", O_WRONLY);
    if (fd < 0) {
        LOGE("Failed to open export for writing!\n");
        return(0);
    }
    LOGE("sizeof(buffer) : %d", sizeof(buffer));
    len = snprintf(buffer, BUFFER_MAX, "%d", gpio);
    LOGE("gpio : %d , len : %d, buffer : %s , sizeof(buffer) : %d", gpio, len, buffer, sizeof(buffer));
    if (write(fd, buffer, len) < 0) {
        LOGE("Fail to export gpio!\n");
        return 0;
    }

    close(fd);
    return 1;
}

/*
 * Class:     com_zhuang_jnigpio_GPIOControl
 * Method:    setGpioDirection
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_setGpioDirection(JNIEnv *env, jobject instance, jint gpio, jint direction)
{
    static const char dir_str[]  = "in\0out";
    char path[DIRECTION_MAX];
    int fd;

    snprintf(path, DIRECTION_MAX, "/sys/class/gpio/gpio%d/direction", gpio);
    LOGE("path : %s", path);
    fd = open(path, O_WRONLY);
    if (fd < 0) {
        LOGE("failed to open gpio direction for writing!\n");
        return 0;
    }

    if (write(fd, &dir_str[direction == IN ? 0 : 3], direction == IN ? 2 : 3) < 0) {
        LOGE("failed to set direction!\n");
        return 0;
    }

    close(fd);
    return 1;
}

/*
 * Class:     com_zhuang_jnigpio_GPIOControl
 * Method:    readGpioStatus
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_readGpioStatus(JNIEnv *env, jobject instance, jint gpio)
{
    char path[DIRECTION_MAX];
    char value_str[3];
    int fd;

    snprintf(path, DIRECTION_MAX, "/sys/class/gpio/gpio%d/value", gpio);
    fd = open(path, O_RDONLY);
    if (fd < 0) {
        LOGE("failed to open gpio value for reading!\n");
        return -1;
    }

    if (read(fd, value_str, 3) < 0) {
        LOGE("failed to read value!\n");
        return -1;
    }

    close(fd);
    return (atoi(value_str));
}

/*
 * Class:     com_zhuang_jnigpio_GPIOControl
 * Method:    writeGpioStatus
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_writeGpioStatus(JNIEnv *env, jobject instance, jint gpio, jint value)
{
    static const char values_str[] = "01";
    char path[DIRECTION_MAX];
    int fd;

    snprintf(path, DIRECTION_MAX, "/sys/class/gpio/gpio%d/value", gpio);
    fd = open(path, O_WRONLY);
    if (fd < 0) {
        LOGE("failed to open gpio value for writing!\n");
        return 0;
    }

    if (write(fd, &values_str[value == LOW ? 0 : 1], 1) < 0) {
        LOGE("failed to write value!\n");
        return 0;
    }

    close(fd);
    return 1;
}

/*
 * Class:     com_zhuang_jnigpio_GPIOControl
 * Method:    unexportGpio
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_com_example_beep_GpioCtr_unexportGpio(JNIEnv *env, jobject instance, jint gpio)
{
    char buffer[BUFFER_MAX];
    int len;
    int fd;

    fd = open("/sys/class/gpio/unexport", O_WRONLY);
    if (fd < 0) {
        LOGE("Failed to open unexport for writing!\n");
        return 0;
    }

    len = snprintf(buffer, BUFFER_MAX, "%d", gpio);
    if (write(fd, buffer, len) < 0) {
        LOGE("Fail to unexport gpio!");
        return 0;
    }

    close(fd);
    return 1;
}

2、java初始化本地方法

package com.example.beep;

/**
 * Created by Administrator on 2018/12/1.
 */
public class GpioCtr {

    static {
        System.loadLibrary("GpioCtr");
    }

    public final static native int exportGpio(int gpio);
    public final static native int setGpioDirection(int gpio, int direction);
    public final static native int readGpioStatus(int gpio);
    public final static native int writeGpioStatus(int gpio, int value);
    public final static native int unexportGpio(int gpio);

}

3、app调用部分代码

package com.example.beep;

import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;


public class MainActivity extends AppCompatActivity {
	Buzzer bz = new Buzzer();
	static int BEEP = 228 ;
	static int LED5 = 362;
	static int LED6 = 361;
	static int flag1 = 0;
	static int flag2 = 0;
	static int flag3 = 0;
	//String out="out";
	//String in ="in";
	static int out = 1;
	static int in = 0;


	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		//bz.export(BEEP);
		//bz.export(LED5);
		//bz.export(LED6);
		GpioCtr.exportGpio(BEEP);
		GpioCtr.exportGpio(LED5);
		GpioCtr.exportGpio(LED6);
		setContentView(R.layout.activity_main);

		final Button mybutton1 = (Button) findViewById(R.id.beep);
		final Button mybutton2 = (Button) findViewById(R.id.led5);
		final Button mybutton3 = (Button) findViewById(R.id.led6);

		mybutton1.setOnClickListener(new View.OnClickListener() {
			@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
			public void onClick(View v) {
			if(flag1==0){
				flag1 = 1;
				v.setBackground(getResources().getDrawable(R.drawable.beep_on));
				//bz.gpio(BEEP,out,flag1);
				GpioCtr.setGpioDirection(BEEP, out);
				GpioCtr.writeGpioStatus(BEEP, flag1);
			}else {
				flag1 = 0;
				v.setBackground(getResources().getDrawable(R.drawable.beep_off));
				//bz.gpio(BEEP,in,flag1);
				GpioCtr.setGpioDirection(BEEP, in);
				GpioCtr.writeGpioStatus(BEEP, flag1);
				}
			}
		});
		mybutton2.setOnClickListener(new View.OnClickListener() {
			@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
			public void onClick(View v) {
				if(flag2==0){
					flag2=1;
					v.setBackground(getResources().getDrawable(R.drawable.light_on));
					GpioCtr.setGpioDirection(LED5, out);
					GpioCtr.writeGpioStatus(LED5, flag2);
					//bz.gpio(LED5,out,flag2);
				}else {
					flag2=0;
					v.setBackground(getResources().getDrawable(R.drawable.light_off));
					GpioCtr.setGpioDirection(LED5, in);
					GpioCtr.writeGpioStatus(LED5, flag2);
					//bz.gpio(LED5,in,flag2);
				}
			}
		});
		mybutton3.setOnClickListener(new View.OnClickListener() {
			@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
			public void onClick(View v) {
				if(flag3==0){
					flag3=1;
					v.setBackground(getResources().getDrawable(R.drawable.light_on));
					//bz.gpio(LED6,out,flag3);
					GpioCtr.setGpioDirection(LED6, out);
					GpioCtr.writeGpioStatus(LED6, flag3);
				}else {
					flag3=0;
					v.setBackground(getResources().getDrawable(R.drawable.light_off));
					//bz.gpio(LED6,in,flag3);
					GpioCtr.setGpioDirection(LED6, in);
					GpioCtr.writeGpioStatus(LED6, flag3);
				}
			}
		});
	}
		protected void onStop() {
			super.onStop();
			//bz.unexport(BEEP);
			//bz.unexport(LED5);
			//bz.unexport(LED6);
			GpioCtr.unexportGpio(BEEP);
			GpioCtr.unexportGpio(LED5);
			GpioCtr.unexportGpio(LED6);
		}




}

4、app/gradle里面添加ndk配置

ndk{
            moduleName "GpioCtr" //so文件: lib+moduleName+.so
            ldLibs "log", "z", "m" // 添加android日志引用
            //abiFilters "all"//cpu的类型
            abiFilters "armeabi-v7a", "x86"
        }

5、local.properties中添加sdk和ndk目录

ndk.dir=D\:\\Users\\Administrator\\AppData\\Local\\Android\\android-ndk-r12b-windows-x86_64\\android-ndk-r12b
sdk.dir=D\:\\Users\\Administrator\\AppData\\Local\\Android\\sdk

6、gradle.properties中添加配置

android.useDeprecatedNdk=true  （我自己试了这句不加也可以，你们也试试看）

最后运行安装完成