android平台开发之框架层

三,框架层(framework)

   这里主要实现两部分

(1: 为Android HAL编写JNI方法，以便使得上层的APP能够使用下层提供的硬件服务

(2: 在Android系统的框架层提供Java接口的硬件服务

1,在frameworks/base/services/jni中新建com_android_server_swtled.cpp

#define LOG_TAG "SwtledService"
#include "jni.h"
#include "JNIHelp.h"
#include "android_runtime/AndroidRuntime.h"
#include <utils/misc.h>
#include <utils/Log.h>
#include <hardware/hardware.h>
#include <hardware/swtled.h>
#include <stdio.h>



namespace android
{
    struct swtled_device_t* swtled_device = NULL;


    static void swtled_set_on(JNIEnv* env, jobject clazz,jint number)
    {
        int num = number;
        LOGI("Swtled JNI: select lighton is %d",num);

        if (!swtled_device)
        {
            LOGI("Swtled JNI:device is not open.");
            return;
        }
        swtled_device->set_on(swtled_device,num);
    }

    static void swtled_set_off(JNIEnv* env, jobject clazz,jint number)
    {

        int num = number;
        LOGI("Swtled JNI: select lightoff is %d",num);

        if (!swtled_device)
        {
            LOGI("Swtled JNI:device is not open.");
            return;
        }
        swtled_device->set_off(swtled_device,num);
    }

    static inline int swtled_device_open(hw_module_t* module,swtled_device_t** device)
    {
        return module->methods->open(module,SWTLED_HARDWARE_MODULE_ID,(hw_device_t**)device);
    }


    static jboolean swtled_init(JNIEnv* env,jclass clazz)
    {
        swtled_module_t* swtledmodule;

        LOGI("Swtled JNI: initializing...");

        if (hw_get_module(SWTLED_HARDWARE_MODULE_ID,(const struct hw_module_t**)&swtledmodule)==0)
        {
            LOGI("Swtled JNI: swtled stub be found.");
            if (swtled_device_open(&(swtledmodule->common),&swtled_device) == 0)
            {
                LOGI("Swtled JNI: swtled device open successful.");
                return 0;
            }

            LOGI("Swtled JNI: failed to open swtled device.");
            return -1;
        }

        LOGI("Swtled JNI: failed to get swtled stub module.");
        return -1;
     }

     static const JNINativeMethod method_table[] =
     {
        {"init_native", "()Z", (void*)swtled_init},
        {"setOn_native","(I)V",(void*)swtled_set_on},
        {"setOff_native","(I)V",(void*)swtled_set_off},
     };

    int register_android_server_SwtledService(JNIEnv* env)
    {
        return jniRegisterNativeMethods(env,"com/android/server/SwtledService",method_table,NELEM(method_table));
    }
}

修改同级目录下的Android.mk和Onload.cpp文件

在Android.mk的LOCAL_SRC_FILES:=下添加

LOCAL_SRC_FILES:= \
....
com_android_server_swtled.cpp \

在Onload.cpp中的namespace android {  下加入

int register_android_server_SwtledService(JNIEnv* env);

同时在JNI_OnLoad函数下加入

register_android_server_SwtledService(env);

2,编译

   (1,执行mmm framework/base/services/jni

   (2,make snod

3,在frameworks/base/core/java/android/os 新建ISwtledService.aidl,代码如下

package android.os;



interface ISwtledService {

    void setOn(int number);

    void setOff(int number);

}

返回到frameworks/base目录，打开Android.mk文件，修改LOCAL_SRC_FILES变量的值，增加 ISwtledService.aidl源文件

LOCAL_SRC_FILES += /

....................................................................

core/java/android/os/IVibratorService.aidl /

core/java/android/os/ISwtledService.aidl /

core/java/android/service/urlrenderer/IUrlRendererService.aidl /

4,编译ISwtledService接口

  mmm framework/base,如果正确,那么会根据ISwtledService.aidl生成对应的ISwtledService.Stub接口

 

5，进入到frameworks/base/services/java/com/android/server目录，新增ISwtledService.java文件：

package com.android.server;
import android.content.Context;
import android.os.ISwtledService;
import android.util.Slog;


public class SwtledService extends ISwtledService.Stub {

    private static final String TAG = "SwtledService";

    SwtledService()
    {
        init_native();
    }

    public void setOn(int number)
    {
        setOn_native(number);
    }

    public void setOff(int number)
    {
        setOff_native(number);
    }

    private static native boolean init_native();
    private static native void setOn_native(int number);
    private static native void setOff_native(int number);
};

6，修改同目录下的SystemServer.java文件，在ServerThread::run方法里加入

try{

                Slog.i(TAG, "Swtled Service");
                ServiceManager.addService("swtled", new SwtledService());
            } catch (Throwable e) {
                Slog.e(TAG, "Failure starting Swtled Service", e);
            }

7，编译SwtledService.java并打包进system.img

   （1）mmm framework/base/services/java
   （2）make snod