创Android Applicationproject：采用Eclipse的Android插入ADT创Androidproject，project名字Gpio，创建完成后，project文件夹packages/apps/文件夹下，并删除project文件夹下的gen文件夹。不删除的话会造成类反复的错误。
src/com/android/gpio/Gpio.java：
package com.android.gpio; import com.android.gpio.R; import android.app.Activity; import android.os.ServiceManager; import android.os.Bundle; import android.os.IGpioService; import android.os.RemoteException; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class Gpio extends Activity implements OnClickListener { private final static String LOG_TAG = "com.android.Gpio"; private IGpioService gpioService = null; private Button setButton = null; private Button clearButton = null; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); gpioService = IGpioService.Stub.asInterface( ServiceManager.getService("gpio")); setButton = (Button)findViewById(R.id.button_set); clearButton = (Button)findViewById(R.id.button_clear); setButton.setOnClickListener(this); clearButton.setOnClickListener(this); } @Override public void onClick(View v) { if(v.equals(setButton)) { try{ int val='1'; gpioService.setVal(val); } catch (RemoteException e){ Log.e(LOG_TAG,"setting value"); } } else if(v.equals(clearButton)) { try{ int val='0'; gpioService.setVal(val); } catch (RemoteException e){ Log.e(LOG_TAG,"setting value"); } } } }布局res/layout/main.xml： xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <Button android:id="@+id/button_clear" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/clear" android:textStyle="bold" android:layout_marginTop="140dp"/> <Button android:id="@+id/button_set" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/set" android:textStyle="bold" android:layout_marginTop="0dp"/> </LinearLayout>
字符串res/values/strings.xml：> <resources> <string name="app_name">GPIO</string> <string name="set">Set</string> <string name="clear">Clear</string> </resources>
AndroidManifest.xml：xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.android.gpio" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name"> <activity android:name=".Gpio" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
编辑project文件夹下Android.mk：LOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := optionalLOCAL_SRC_FILES := $(call all-subdir-java-files)LOCAL_PACKAGE_NAME := GpioLOCAL_CERTIFICATE := platforminclude $(BUILD_PACKAGE)include $(call all-makefiles-under,$(LOCAL_PATH))编辑build/target/product/generic_no_telephony.mk：
在PRODUCT_PACKAGES := \ 后增加Gpio \
编译project会生成Gpio.apk
make TARGET_PRODUCT=am335xevm_sk -j8 OMAPES=4.x到这一步一切准备工作都已就绪，開始更新目标板am335evm的文件系统：(左为host，右为evm)
out/target/product/am335xevm_sk/system/app/Gpio.apk ==> rootfs/out/target/product/am335xevm_sk/system/framework/services.jar ==> rootfs/system/framework/out/target/product/am335xevm_sk/system/framework/framework.jar ==> rootfs/system/framework/out/target/product/am335xevm_sk/obj/lib/libandroid_servers.so ==> rootfs/system/lib/out/target/product/am335xevm_sk/obj/lib/gpio.default.so ==> rootfs/system/lib/hw/
确保rootfs下 ueventd.rc 已经加入：( 提到)
/dev/AdrIO 0666 root root启动，安装Gpio.apk。打开GPIO：
现象：
点击"Set"button： D1灯亮 点击"Clear"button： D1灯灭
可见编写的APP通过调用硬件服务已经成功操作了AM335寄存器，改变AM335X_GPIO_LED4级别。经N渎MOS设备控制LED D1灯灭。
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