Android 從硬體到應用：一步一步向上爬 6，android一步一步

Android 從硬體到應用：一步一步向上爬 6，android一步一步

       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：

<?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>  

字串res/values/strings.xml：

<?xml version="1.0" encoding="utf-8"?>  <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>   

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。