第一步：首先在linux下添加驅動
1.查看原理圖，找出未使用的引腳，這裏是：GPJ0_0 GPJ0_1
2.添加char字符設備驅動，找到LINUX源代碼下的char設備驅動路徑: FriendlyArm /Linux3.0.8/ Drivers/char/目錄，在目錄下新建裏一個文件lzm_fjicc.c 用來寫驅動用。
需要註冊設備、設備的打開、關閉、取消設備等操作。
源代碼如綜合實驗一：
第二步：建立Android測試代碼，第一步要實現.so文件：
1.打開eclipseàFileàNewàAndroid Application Projectcom.example.TEST
2.新建jni文件夾，在文件夾內新建兩個文件：test-jni.c和Android.mk
Android.mk內容如下：
# 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內容如下：
/*
* 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
#defineDEV_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 );//調用驅動程序中的ioctrl接口，把命令傳下去，實現硬件操作
break;
}
case VIB_OFF:
{
ioctl(fd,0,ledid);////setLedState( 0, 0 );//調用驅動程序中的ioctrl接口，把命令傳下去，實現硬件操作
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;
}
注意如果需要頭文件Alog.h需要自己寫，然後放在jni文件夾下的
#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)
3.建立完畢，打開Cygwin工具，並進入到工程目錄下的jni目錄下：
$ cd d:/Program/Android/workspace/TEST /jni
$$NDK/ndk-build
這樣就OK了，生成了libtest-jni.so文件了，自動生成到了工程目錄下的libs/armeabi/ libtest-jni.so，發現test-jni是我們剛纔在.mk文件裏面的命名。
第三步：寫應用程序：
1.在應用程序類com.example.TEST目錄下建立一個類：TESTCLASS.java，輸入如下代碼，這是用來引用libtest-jni.so文件的。
package com.example.TEST;
import android.util.Log;
publicclass TESTCLASS {
publicnative String stringFromJNI();
publicnativeint OPEN();
publicnativeint IOCTL(int fd,int controlcode,int ledID);
publicnativeint CLOSE(int fd);
static {
try {
System.loadLibrary("test-jni");
} catch (UnsatisfiedLinkError e) {
Log.d("HardwareControler", "HardwareControler ibrary not found!");
}
}
}
2.編寫應用程序，調用TESTCLASS類中的函數OPEN()/CLOSE()/IOCTL()就可以實現底層的控制了。
添加按鈕，用來打開和關閉LED燈,以及關閉驅動
<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.編寫MainActivity，添加響應函數：
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();
//修改驅動的權限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, "沒有打開設備", Toast.LENGTH_SHORT).show();
else
Toast.makeText(MainActivity.this, "打開設備", 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, "設備未打開，無需關閉", 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();
}
}
}
問題一：android NDK jni下的c文件 Unresolved inclusion
原因是在eclipse編輯環境中沒有找到對應的include中的文件。解決方法是將包含該文件的include目錄作爲新的linked folder加入工程中。具體方法如下：
1. 右擊工程->New->Folder
2. 對話框中點擊Advanced
3. 選擇Link to alternate location (Linked Folder)，選擇需要的include目錄
4. Finish後刷新工程，問題解決。
include 目錄可以在ndk的安裝目錄中找到
比如：在安裝的NDK目錄下找到/NDKDir/android-ndk-r7b/platforms/android-8/arch-arm/usr/include
問題二：在android裏使用JNI，總是報錯：insomethingnotastructureorunion
error:requestformember'GetStringUTFChars'insomethingnotastructureorunion
問題解決了，原來是這樣的：
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->”編譯會找不到此結構，必須用“(*env)->”，或者改成.cpp文件，以c++的方式來編譯
以下是兩者的區別：
jni.h中
structJNINativeInterface_;
structJNIEnv_;
#ifdef__cplusplus
typedefJNIEnv_JNIEnv;
#else
typedefconststructJNINativeInterface_*JNIEnv;
#endif
/*
*WeuseinlinedfunctionsforC++sothatprogrammerscanwrite:
*env->FindClass("java/lang/String")
*inC++ratherthan:
*(*env)->FindClass(env,"java/lang/String")
*inC.
*/
即C++中使用
env->FindClass("java/lang/String")
C中使用
(*env)->FindClass(env,"java/lang/String")
問題三：直接在應用程序中獲取驅動的可執行權限#chmod 777
//用來修改驅動的權限問題否則需要在終端輸入 #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();
}
}
問題四：S5VP210端口設置小結
//定義用到的引腳S5PV210_GPJ0(7)
//設置引腳的輸出
s3c_gpio_cfgpin(S5PV210_GPJ0(7),S3C_GPIO_SFN(1));//設置爲輸出
gpio_direction_output(S5PV210_GPJ0(7),0);
//釋放總線
#define OW_Pin S5PV210_GPJ0(7)
s3c_gpio_cfgpin(OW_Pin,S3C_GPIO_SFN(0));//設置爲輸入
s3c_gpio_setpull(OW_Pin,S3C_GPIO_PULL_UP);
gpio_get_value(OW_Pin)//獲取引腳的輸入電平狀態