此方案实现Android APP控制CPU GPIO，支持设置IO方向、输出、输入、按键功能。
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移植驱动与Framework gpio service
API调用方法
方法1 依赖Framework jar包（不推荐）
- 引入Android定制后的Framework jar包，out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/classes.jar
- 将classes.jar拷贝到app/libs/目录下
- 修改项目根目录build.gradle，在allprojects段内增加下面代码：
allprojects { repositories { google() jcenter() } gradle.projectsEvaluated { tasks.withType(JavaCompile) { options.compilerArgs.add('-Xbootclasspath/p:app\\libs\\classes.jar') } } }- 修改app/build.gradle，如下：
android{ defaultConfig { multiDexEnabled true } } dependencies { compileOnly files('libs/classes.jar') } preBuild { doLast { def imlFile = file(project.name + ".iml") println('Change ' + project.name + '.iml order') try { def parsedXml = (new XmlParser()).parse(imlFile) def jdkNode = parsedXml.component[1].orderEntry.find { it.'@type' == 'jdk' } parsedXml.component[1].remove(jdkNode) def sdkString = "Android API " + android.compileSdkVersion.substring("android-".length()) + " Platform" new groovy.util.Node(parsedXml.component[1], 'orderEntry', ['type': 'jdk', 'jdkName': sdkString, 'jdkType': 'Android SDK']) groovy.xml.XmlUtil.serialize(parsedXml, new FileOutputStream(imlFile)) } catch (FileNotFoundException e) { // nop, iml not found } } } - 调用
SystemGpio gpioService = (SystemGpio) context.getSystemService("gpio");
方法二 反射调用（==推荐==）
- 在APP源码src/main目录下新建aidl/android/os/这样的目录结构
- 在aidl/android/os/目录下新建IGpioService.aidl文件，内容如下：
package android.os;
/** {@hide} */
interface IGpioService
{
int gpioWrite(int gpio, int value);
int gpioRead(int gpio);
int gpioDirection(int gpio, int direction, int value);
int gpioRegKeyEvent(int gpio);
int gpioUnregKeyEvent(int gpio);
int gpioGetNumber();
}
- 反射调用
Method method = null;
try {
method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder binder = (IBinder) method.invoke(null, new Object[]{"gpio"});
IGpioService gpioService = IGpioService.Stub.asInterface(binder);
} catch (Exception e) {
e.printStackTrace();
}
API使用说明
获取GPIO数量
在使用GPIO前建议先获取GPIO数量，当调用其它方法需要传入参数“gpio”时可以使用0~Number之间的值。
如：gpioGetNumber()返回7，说明一共有7个GPIO，那么传入参数可以为：0、1、2、3、4、5、6。
/**
* Get GPIO number
* @return <0: error other: GPIO number
*/
public int gpioGetNumber() {
if (null != mGpioService) {
return mGpioService.gpioGetNumber();
}
return -1;
}
设置输入输出模式
/**
* GPIO direction
* @param gpio 0~Number
* @param direction 0: input 1: output
* @param value 0: Low 1: High
*/
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
mGpioService.gpioDirection(gpio, direction, value);
}
}
控制GPIO输出
/**
* GPIO write
* @param gpio 0~Number
* @param value 0: Low 1: High
*/
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
mGpioService.gpioWrite(gpio, value);
}
}
控制GPIO输入
/**
* GPIO read
* @param gpio 0~Number
* @return 0: Low 1: High other：error
*/
public int gpioRead(int gpio) {
if (null != mGpioService) {
return mGpioService.gpioRead(gpio);
}
return -1;
}
设置GPIO为按键模式
/**
* GPIO register key event
* @param gpio 0~Number
*/
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioRegKeyEvent(gpio);
}
}
设置为按键模式后，当GPIO有电平翻转时会上报按键事件，GPIO与KeyCode对应关系如下：
GPIO_0 KeyEvent.KEYCODE_GPIO_0
GPIO_1 KeyEvent.KEYCODE_GPIO_1
GPIO_2 KeyEvent.KEYCODE_GPIO_2
GPIO_3 KeyEvent.KEYCODE_GPIO_3
GPIO_4 KeyEvent.KEYCODE_GPIO_4
GPIO_5 KeyEvent.KEYCODE_GPIO_5
GPIO_6 KeyEvent.KEYCODE_GPIO_6
GPIO_7 KeyEvent.KEYCODE_GPIO_7
GPIO_8 KeyEvent.KEYCODE_GPIO_8
GPIO_9 KeyEvent.KEYCODE_GPIO_9
- 当GPIO变为低电平将上报：KeyEvent.ACTION_DOWN
- 当GPIO变为高电平将上报：KeyEvent.ACTION_UP
如果要取消按键模式则调用如下方法：
/**
* GPIO unregister key event
* @param gpio 0~Number
*/
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioUnregKeyEvent(gpio);
}
}
例
依赖Framework jar方式参考源码：
package com.ayst.item;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.SystemGpio;
/**
* Created by Administrator on 2018/11/6.
*/
public class GpioTest {
private SystemGpio mGpioService;
@SuppressLint("WrongConstant")
public GpioTest(Context context) {
mGpioService = (SystemGpio) context.getSystemService("gpio");
}
/**
* GPIO write
* @param gpio 0~Number
* @param value 0: Low 1: High
*/
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
mGpioService.gpioWrite(gpio, value);
}
}
/**
* GPIO read
* @param gpio 0~Number
* @return 0: Low 1: High other：error
*/
public int gpioRead(int gpio) {
if (null != mGpioService) {
return mGpioService.gpioRead(gpio);
}
return -1;
}
/**
* GPIO direction
* @param gpio 0~Number
* @param direction 0: input 1: output
* @param value 0: Low 1: High
*/
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
mGpioService.gpioDirection(gpio, direction, value);
}
}
/**
* GPIO register key event
* @param gpio 0~Number
*/
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioRegKeyEvent(gpio);
}
}
/**
* GPIO unregister key event
* @param gpio 0~Number
*/
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioUnregKeyEvent(gpio);
}
}
/**
* Get GPIO number
* @return <0: error other: GPIO number
*/
public int gpioGetNumber() {
if (null != mGpioService) {
return mGpioService.gpioGetNumber();
}
return -1;
}
}
反射方式参考源码：
package com.ayst.item;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.IBinder;
import android.os.IGpioService;
import android.os.RemoteException;
import java.lang.reflect.Method;
/**
* Created by Administrator on 2018/11/6.
*/
public class GpioTest {
private IGpioService mGpioService;
@SuppressLint("WrongConstant")
public GpioTest(Context context) {
Method method = null;
try {
method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder binder = (IBinder) method.invoke(null, new Object[]{"gpio"});
mGpioService = IGpioService.Stub.asInterface(binder);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* GPIO write
*
* @param gpio 0~Number
* @param value 0: Low 1: High
*/
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
try {
mGpioService.gpioWrite(gpio, value);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
/**
* GPIO read
*
* @param gpio 0~Number
* @return 0: Low 1: High other：error
*/
public int gpioRead(int gpio) {
if (null != mGpioService) {
try {
return mGpioService.gpioRead(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
return -1;
}
/**
* GPIO direction
*
* @param gpio 0~Number
* @param direction 0: input 1: output
* @param value 0: Low 1: High
*/
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
try {
mGpioService.gpioDirection(gpio, direction, value);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
/**
* GPIO register key event
*
* @param gpio 0~Number
*/
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
try {
mGpioService.gpioRegKeyEvent(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
/**
* GPIO unregister key event
*
* @param gpio 0~Number
*/
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
try {
mGpioService.gpioUnregKeyEvent(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
/**
* Get GPIO number
*
* @return <0: error other: GPIO number
*/
public int gpioGetNumber() {
if (null != mGpioService) {
try {
return mGpioService.gpioGetNumber();
} catch (RemoteException e) {
e.printStackTrace();
}
}
return -1;
}
}
