JNI综合实验二：IO控制及驱动打开与关闭
第一步：首先在linux下添加驱动
1.查看原理图，找出未使用的引脚，这里是：GPJ0_0 GPJ0_1
2.添加char字符设备驱动，找到LINUX源代码下的char设备驱动路径: FriendlyArm /Linux3.0.8/ Drivers/char/目录，在目录下新建里一个文件lzm_fjicc.c 用来写驱动用。
需要注册设备、设备的打开、关闭、取消设备等操作。
源代码如综合实验一：
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第二步：建立Android测试代码，第一步要实现.so文件：
1.打开eclipseàFileàNewàAndroid Application Project? com.example.TEST
2.新建jni文件夹，在文件夹内新建两个文件：test-jni.c和Android.mk
Android.mk内容如下：
# Copyright (C) 2009 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#????? http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
LOCAL_PATH := $(call my-dir)
?
include$(CLEAR_VARS)
?
LOCAL_MODULE??? := test-jni
LOCAL_SRC_FILES := test-jni.c
?
include$(BUILD_SHARED_LIBRARY)
jni0922.c内容如下：
/*
?* Copyright (C) 2009 The Android Open Source Project
?*
?* Licensed under the Apache License, Version 2.0 (the "License");
?* you may not use this file except in compliance with the License.
?* You may obtain a copy of the License at
?*
?*????? http://www.apache.org/licenses/LICENSE-2.0
?*
?* Unless required by applicable law or agreed to in writing, software
?* distributed under the License is distributed on an "AS IS" BASIS,
?* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
?* See the License for the specific language governing permissions and
?* limitations under the License.
?*
?*/
#include<termios.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<sys/ioctl.h>
#include<fcntl.h>
#include<string.h>
#include<jni.h>
#include<errno.h>
//#include <utils/Log.h>
//#include <system.h>
?
#define VIB_ON 0x11
#define VIB_OFF 0x22
?
?
?
#define? DEV_NAME "/dev/LZM_FJICC"
/* This is a trivial JNI example where we use a native method
?* to return a new VM String. See the corresponding Java source
?* file located at:
?*
?*?? /project/app/TEST/src/com.example.TEST/MainActivity.java
?*?? /project/app/TEST/src/com.example.TEST/TESTCLASS.java
?*/
jstring
Java_com_example_TEST_TESTCLASS_stringFromJNI( JNIEnv* env, jobject thiz )
{
??? return (*env)->NewStringUTF(env, "Hello from JNI !");
}
?
jint
Java_com_example_TEST_TESTCLASS_IOCTL( JNIEnv* env, jobject thiz, jint fd ,jint controlcode,jint ledid)
{
?????? /* LED */
??? int CTLCODE = controlcode;
??? int value =-1;
??? switch(CTLCODE)
??? {? case VIB_ON:
????????????? {
????????????? ioctl(fd,1,ledid);//setLedState( 0, 1 );//调用驱动程序中的ioctrl接口，把命令传下去，实现硬件操作
????????????? break;
????????????? }
??? ?? case VIB_OFF:
??? ?? ??????{
??? ?? ???????ioctl(fd,0,ledid);////?? ? setLedState( 0, 0 );//调用驱动程序中的ioctrl接口，把命令传下去，实现硬件操作
??? ?? ??????break;
??? ?? ??????}
?
??? ?? default:break;
??? ?}
?????? return fd;
}
?
jint
Java_com_example_TEST_TESTCLASS_OPEN(JNIEnv* env,jobject thiz)
{
?
??? ? jint fd;
??? ? fd=open(DEV_NAME,O_RDWR);
??? ? return fd;
}
?
jint
Java_com_example_TEST_TESTCLASS_CLOSE( JNIEnv* env, jobject thiz, jint fd)
{
?????? ?jint ret;
?????? ?ret = close(fd);
?????? ?return ret;
}
?
?
注意如果需要头文件Alog.h需要自己写，然后放在jni文件夹下的
#pragma once
#include<android/log.h>
#define LOG_TAG "debug log"
#define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, fmt, ##args)
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, fmt, ##args)
#define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, fmt, ##args)
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?
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3.建立完毕，打开Cygwin工具，并进入到工程目录下的jni目录下：
$ cd d:/Program/Android/workspace/TEST /jni
$$NDK/ndk-build
?
这样就OK了，生成了libtest-jni.so文件了，自动生成到了工程目录下的libs/armeabi/ libtest-jni.so，发现test-jni是我们刚才在.mk文件里面的命名。
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第三步：写应用程序：
1.在应用程序类com.example.TEST目录下建立一个类：TESTCLASS.java，输入如下代码，这是用来引用libtest-jni.so文件的。
package com.example.TEST;
?
import android.util.Log;
?
publicclass TESTCLASS {
?
public? native String stringFromJNI();
public? nativeint OPEN();
public? nativeint IOCTL(int fd,int controlcode,int ledID);
public? nativeint CLOSE(int fd);
?
static {
??? try {
??? System.loadLibrary("test-jni");
??? } catch (UnsatisfiedLinkError e) {
??????? Log.d("HardwareControler", "HardwareControler ibrary not found!");
??? }
}
}
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2.编写应用程序，调用TESTCLASS类中的函数OPEN()/CLOSE()/IOCTL()就可以实现底层的控制了。
添加按钮，用来打开和关闭LED灯,以及关闭驱动
<Button
??????????? android:id="@+id/button1"
??????????? style="?android:attr/buttonStyleSmall"
??????????? android:layout_width="wrap_content"
??????????? android:layout_height="wrap_content"
??????????? android:layout_gravity="center_horizontal"
??????????? android:layout_weight="0.76"
??????????? android:text="ON" />
?
??????? <Button
??????????? android:id="@+id/button2"
??????????? style="?android:attr/buttonStyleSmall"
??????????? android:layout_width="wrap_content"
??????????? android:layout_height="wrap_content"
??????????? android:layout_weight="1.26"
??????????? android:text="OFF" />
?
??????? <Button
??????????? android:id="@+id/button5"
??????????? style="?android:attr/buttonStyleSmall"
??????????? android:layout_width="wrap_content"
??????????? android:layout_height="wrap_content"
??????????? android:layout_weight="0.76"
??????????? android:text="close" />
2.编写MainActivity，添加响应函数：
package com.example.TEST;
?
import java.io.DataOutputStream;
import java.io.IOException;
?
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
?
publicclass MainActivity extends Activity {
?
??? private Button btn_on;
??? private Button btn_off,btn_close;
???
??? publicstaticfinalintVIB_ON = 0x11;?
??? publicstaticfinalintVIB_OFF = 0x22;??
??? intfd;
??? intvalue = -1;
??? TESTCLASS mTESTCLASS1;
???
??? @Override
??? protectedvoid onCreate(Bundle savedInstanceState) {
?????? super.onCreate(savedInstanceState);
??????
?????? setContentView(R.layout.activity_main);
?????? mTESTCLASS1 = new TESTCLASS();
?????? String s = mTESTCLASS1.stringFromJNI().toString();
??????
?????? //修改驱动的权限LZM_FJICC
?????? changePerm();
?????????????
?????????????
?????? fd = mTESTCLASS1.OPEN();
?????? Toast.makeText(MainActivity.this, "open,fd="+fd, Toast.LENGTH_SHORT).show();
??????
?????? btn_on = (Button)findViewById(R.id.button1);
?????? btn_off = (Button)findViewById(R.id.button2);???
?????? btn_close= (Button)findViewById(R.id.button5);
??????
??????
??????
??????
?????? if(fd == -1)
?????????? Toast.makeText(MainActivity.this, "没有打开设备", Toast.LENGTH_SHORT).show();
?????? else
?????????? Toast.makeText(MainActivity.this, "打开设备", Toast.LENGTH_SHORT).show();
??????
?????? Toast.makeText(MainActivity.this,""+s, Toast.LENGTH_SHORT).show();
??????
?????? btn_on.setOnClickListener(new Button.OnClickListener(){
?
?????????? @Override
?????????? publicvoid onClick(View arg0) {
????????????? // TODO Auto-generated method stub
????????????? fd=mTESTCLASS1.IOCTL(fd, VIB_ON,0);
????????????? Toast.makeText(MainActivity.this, "ioctl,fd="+fd, Toast.LENGTH_SHORT).show();
?????????? }
?????? });
??????
??????
?????? btn_off.setOnClickListener(new Button.OnClickListener(){
?
?????????? @Override
?????????? publicvoid onClick(View v) {
????????????? // TODO Auto-generated method stub
????????????? mTESTCLASS1.IOCTL(fd, VIB_OFF,0);
?
?????????? }});
??????
??????
??????
?????? btn_close.setOnClickListener(new Button.OnClickListener(){
?
?????????? @Override
?????????? publicvoid onClick(View v) {????????????
?????????? // TODO Auto-generated method stub
????????????? Toast.makeText(MainActivity.this, "close,fd="+fd, Toast.LENGTH_SHORT).show();
????????????? if(fd != -1){
???????????????????? value = mTESTCLASS1.CLOSE(fd);
???????????????????? if(value == -1)
???????????????????????? Toast.makeText(MainActivity.this, "close fail,fd="+value, Toast.LENGTH_SHORT).show();
???????????????????? else
???????????????????????? Toast.makeText(MainActivity.this, "close success,fd="+value, Toast.LENGTH_SHORT).show();
????????????? }else{
????????????? Toast.makeText(MainActivity.this, "设备未打开，无需关闭", Toast.LENGTH_SHORT).show();
????????????? }
?????????? }
??????????
?????? });
??????
???
??? }
???
??? void changePerm()
??? {
??? ??? Process chperm;
??? ??? try {
??? ??????? chperm=Runtime.getRuntime().exec("su");
?
?
??? ?? DataOutputStream os =
??? ????????? new DataOutputStream(chperm.getOutputStream());
??? ??????? os.writeBytes("chmod 777 /dev/LED_LZM_FJICC\n");
??? ??????? os.flush();
?
??? ??????? os.writeBytes("exit\n");
??? ??????? os.flush();
?
??? ????????? chperm.waitFor();
?
??? } catch (IOException e) {
??? ??? // TODO Auto-generated catch block
??? ??? e.printStackTrace();
??? } catch (InterruptedException e) {
??? ??? // TODO Auto-generated catch block
??? ??? e.printStackTrace();
??? }
??? }
}
问题一：android NDK jni下的c文件 Unresolved inclusion
原因是在eclipse编辑环境中没有找到对应的include中的文件。解决方法是将包含该文件的include目录作为新的linked folder加入工程中。具体方法如下：
1. 右击工程->New->Folder
2. 对话框中点击Advanced
3. 选择Link to alternate location (Linked Folder)，选择需要的include目录
4. Finish后刷新工程，问题解决。
include 目录可以在ndk的安装目录中找到
比如：在安装的NDK目录下找到/NDKDir/android-ndk-r7b/platforms/android-8/arch-arm/usr/include
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问题二：在android?里使用JNI，总是报错：in?something?not?a?structure?or?union
?error:?request?for?member?'GetStringUTFChars'?in?something?not?a?structure?or?union
问题解决了，原来是这样的：
如果是c程序，要用?(*env)->
如果是C++要用?env->
在linux下如果.c文件中用?“env->”?编译会找不到此结构，必须用“(*env)->”，或者改成.cpp文件，以?c++的方式来编译
以下是两者的区别：
jni.h中
struct?JNINativeInterface_;
struct?JNIEnv_;
#ifdef?__cplusplus
typedef?JNIEnv_?JNIEnv;
#else
typedef?const?struct?JNINativeInterface_?*JNIEnv;
#endif
/*
*?We?use?inlined?functions?for?C++?so?that?programmers?can?write:
*???env->FindClass("java/lang/String")
*?in?C++?rather?than:
*????(*env)->FindClass(env,?"java/lang/String")
*?in?C.
*/
即C++中使用
env->FindClass("java/lang/String")
C中使用
(*env)->FindClass(env,?"java/lang/String")
?
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问题三：直接在应用程序中获取驱动的可执行权限#chmod 777
//用来修改驱动的权限问题否则需要在终端输入 #chmod 777 /dev/LZM_FJICC
??? void changePerm()
??? {
??? ??? Process chperm;
??? ??? try {
??? ??????? chperm=Runtime.getRuntime().exec("su");
??? ?? DataOutputStream os =
??? ????????? new DataOutputStream(chperm.getOutputStream());
??? ??????? os.writeBytes("chmod 777 /dev/LZM_FJICC\n");
??? ??????? os.flush();
??? ??????? os.writeBytes("exit\n");
??? ??????? os.flush();
??? ????????? chperm.waitFor();
??? } catch (IOException e) {
??? ??? // TODO Auto-generated catch block
??? ??? e.printStackTrace();
??? } catch (InterruptedException e) {
??? ??? // TODO Auto-generated catch block
??? ??? e.printStackTrace();
??? }
??? }
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问题四：S5VP210端口设置小结
//???? 定义用到的引脚?? S5PV210_GPJ0(7)
//? 设置引脚的输出
?????? s3c_gpio_cfgpin(S5PV210_GPJ0(7),S3C_GPIO_SFN(1));//设置为输出
?????? gpio_direction_output(S5PV210_GPJ0(7),0);
?
//释放总线
?#define OW_Pin S5PV210_GPJ0(7)
?????? s3c_gpio_cfgpin(OW_Pin,S3C_GPIO_SFN(0));//设置为输入
?????? s3c_gpio_setpull(OW_Pin,S3C_GPIO_PULL_UP);
gpio_get_value(OW_Pin)//获取引脚的输入电平状态
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