Android 從硬體到應用: 編寫APP測試架構層硬體服務(完)
建立Android Application工程:使用Eclipse的Android外掛程式ADT建立Android工程,工程名稱為Gpio,建立完成後將工程目錄拷貝到packages/apps/檔案夾下,並刪除工程目錄下的gen檔案夾,不刪除的話會造成類重複的錯誤。
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:
字串res/values/strings.xml:
GPIO Set Clear
AndroidManifest.xml:
編輯工程目錄下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))
編輯build/target/product/generic_no_telephony.mk:
在PRODUCT_PACKAGES := \ 後加入Gpio \
編譯工程會產生Gpio.apk
make TARGET_PRODUCT=am335xevm_sk -j8 OMAPES=4.x
到這一步一切準備工作都已就緒,開始更新目標板am335evm的檔案系統:(左為host,右為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/
確保rootfs下 ueventd.rc 已經添加:(Android 從硬體到應用:一步一步向上爬 3 -- 硬體抽象層訪問硬體驅動 提到)
/dev/AdrIO 0666 root root
啟動,安裝Gpio.apk,開啟GPIO:
現象:
點擊"Set"按鈕: D1燈亮 點擊"Clear"按鈕: D1燈滅
可見編寫的APP通過調用硬體服務已經成功操作了AM335寄存器,改變AM335X_GPIO_LED4的電平,通過N溝MOS器件控制LED D1的亮滅。