x6818开发板安卓驱动开发(1)-LED-APP

下载 NDK 和构建工具

创建新项目

创建新的c/c++源文件

创建 CMake 构建脚本

CMakeLists.txt

cmake_minimum_required()

add_library()

# Sets the minimum version of CMake required to build your native library.
# This ensures that a certain set of CMake features is available to
# your build.

cmake_minimum_required(VERSION 3.4.1)

# Specifies a library name, specifies whether the library is STATIC or
# SHARED, and provides relative paths to the source code. You can
# define multiple libraries by adding multiple add.library() commands,
# and CMake builds them for you. When you build your app, Gradle
# automatically packages shared libraries with your APK.

add_library( # Specifies the name of the library.
x6818led-lib

# Sets the library as a shared library.
SHARED

# Provides a relative path to your source file(s).
app/src/main/jni/x6818Led.c)

include_directories()

# Specifies a path to native header files.
include_directories(app/src/main/jni/)

target_link_libraries()

target_link_libraries( # Specifies the target library.
x6818led-lib)

将 Gradle 关联到原生库

使用 Android Studio UI

CMakeLists.txt

手动配置 Gradle

externalNativeBuild {}

build.gradle

build.gradle

cmake {}

ndkBuild {}

apply plugin: 'com.android.application'

android {
compileSdkVersion 25
buildToolsVersion "23.0.1"
defaultConfig {...}
buildTypes {...}
externalNativeBuild {
cmake {
path '../CMakeLists.txt'
}
}
}

指定 ABI

.so

build.gradle

build.gradle

ndk.abiFilters

apply plugin: 'com.android.application'

android {
compileSdkVersion 25
buildToolsVersion "23.0.1"
defaultConfig {
...
ndk {
// Specifies the ABI configurations of your native
// libraries Gradle should build and package with your APK.
abiFilters 'x86', 'x86_64', 'armeabi', 'armeabi-v7a', 'arm64-v8a'
}
}
buildTypes {...}
externalNativeBuild {...}
}

创建LED类

package com.wuzs.x6818apptest;

/**
* Created by WZS82 on 2017/5/8.
*/

public class Led {
static {
System.loadLibrary("x6818led-lib");
}
public native int getLedNunmber();
public native boolean getLedStatus(int no);
public native boolean setLedOn(int no);
public native boolean setLedOff(int no);
}

实现JNI调用

//
// Created by WZS82 on 2017/5/8.
//
#include <jni.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>

JNIEXPORT jint JNICALL
Java_com_wuzs_x6818apptest_Led_getLedNunmber(JNIEnv *env, jobject instance)
{
return 4;
}
JNIEXPORT jboolean JNICALL
Java_com_wuzs_x6818apptest_Led_getLedStatus(JNIEnv *env, jobject instance, jint no)
{
if(no < 1 || no > 4)   return 0;
char file[50];
char buf[4];
sprintf(file, "/sys/devices/platform/x6818-leds/led%d",no);
int fd  = open(file,O_RDWR);
int ret = read(fd,buf, 4);
close(fd);
return (buf[0] == '1') ? 1  :0;
}
JNIEXPORT jboolean JNICALL
Java_com_wuzs_x6818apptest_Led_setLedOn(JNIEnv *env, jobject instance, jint no)
{
if(no < 1 || no > 4)   return 0;
char file[50];
sprintf(file, "/sys/devices/platform/x6818-leds/led%d",no);
int fd  = open(file,O_RDWR);
int ret = write(fd,"1", 2);
close(fd);
return (ret == 0) ? 1  :0;
}
JNIEXPORT jboolean JNICALL
Java_com_wuzs_x6818apptest_Led_setLedOff(JNIEnv *env, jobject instance, jint no)
{
if(no < 1 || no > 4)   return 0;
char file[50];
sprintf(file, "/sys/devices/platform/x6818-leds/led%d",no);
int fd  = open(file,O_RDWR);
int ret = write(fd,"0", 2);
close(fd);
return (ret == 0) ? 1  :0;
}