android开发(37) android使用android_serialport_api 操作串口，解决权限问题
最近有个项目，要使用android设备操作串口的 斑马GK888T打印机，使用打印机打印二维码。
硬件设备连接方式：
安卓设备 通过 串口RS232 连接 斑马打印机的串口
那么就要解决：使用安卓设备操作串口的问题。 我找到一个框架：android_serialport_api，这个框架被托管在：
https://code.google.com/p/android-serialport-api/ 谷歌的代码库，无奈国内无法下载
https://github.com/cepr/android-serialport-api GITHUB的地址，这个可以下载
下载后，阅读下源代码，准备使用。
1.拷贝 jni 文件夹下的文件到 你的project中, 这些是jni调用的设定文件，包括:
Android.mk
Application.mk
gen_SerialPort_h.sh
SerialPort.c
SerialPort.h
2.拷贝libs 下的文件到你的 project中，这些是原生库，包括
armeabi/libserial_port.so
armeabi-v7a/libserial_port.so
x86/libserial_port.so
3.在你的项目下新建 package: android_serialport_api，拷贝下列src下的class 到这个package下
Application.java
SerialPort.java
SerialPortActivity.java
SerialPortFinder.java
注意， package名称一定要是android_serialport_api。或者你需要修改Android.mk下对应的模块配置项。不然会提示找不到jni调用的库
4.拷贝资源文件等：
string.xml 的内容：
<string name="error_configuration">Please configure your serial port first.</string>
<string name="error_security">You do not have read/write permission to the serial
port.</string>
<string name="error_unknown">The serial port can not be opened for an unknown
reason.</string>
5.修改AndroidManifest.xml，在application节点指定对应的 "android:name" 配置，如下面红色文字所示
<application android:allowBackup="true" android:name="android_serialport_api.Application" android:theme="@style/AppTheme" >
6.下面写测试的activity。我的设备连接在安卓设备的端口 ”ttyS2”上，下面是个演示：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:keepScreenOn="true" android:orientation="vertical" > <EditText android:id="@+id/EditTextReception" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="7" android:gravity="top" android:hint="Reception" android:isScrollContainer="true" android:scrollbarStyle="insideOverlay" > </EditText> <EditText android:id="@+id/EditTextEmission" android:layout_width="fill_parent" android:layout_height="wrap_content" android:hint="Emission" android:lines="4" android:text="" > </EditText> <Button android:id="@+id/btnSend" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="Send" /> </LinearLayout>
/* * Copyright 2009 Cedric Priscal * * 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. */ package zyf.serialportdemo; import java.io.IOException; import zyf.serialportdemo.R; import android.os.Bundle; import android.view.KeyEvent; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.TextView.OnEditorActionListener; import android_serialport_api.SerialPortActivity; public class ConsoleActivity extends SerialPortActivity { Button btnSend; EditText mReception; EditText mEmission; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.console); // setTitle("Loopback test"); mReception = (EditText) findViewById(R.id.EditTextReception); mEmission = (EditText) findViewById(R.id.EditTextEmission); btnSend = (Button)findViewById(R.id.btnSend); btnSend.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { String text = mEmission.getText().toString(); try { mOutputStream.write(new String(text).getBytes()); mOutputStream.write('\n'); } catch (IOException e) { e.printStackTrace(); } } }); //发送指令到斑马打印机 mEmission.setText("^XA^A0N,40,30^FO50,150^FDHELLO WORLD^FS^XZ");
/*二维码指令
^XA
^PMY
^FO200,200^BQ,2,10
^FDD03040C,LA,012345678912AABBqrcode^FS
^XZ
*/ } @Override protected void onDataReceived(final byte[] buffer, final int size) { runOnUiThread(new Runnable() { public void run() { if (mReception != null) { mReception.append(new String(buffer, 0, size)); } } }); } }
/* * Copyright 2009 Cedric Priscal * * 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. */ package android_serialport_api; import java.io.File; import java.io.IOException; import java.security.InvalidParameterException; import android.content.SharedPreferences; public class Application extends android.app.Application { public SerialPortFinder mSerialPortFinder = new SerialPortFinder(); private SerialPort mSerialPort = null; public SerialPort getSerialPort() throws SecurityException, IOException, InvalidParameterException { if (mSerialPort == null) { /* Read serial port parameters */ //SharedPreferences sp = getSharedPreferences("android_serialport_api.sample_preferences", MODE_PRIVATE); //String path = sp.getString("DEVICE", ""); //String path = "ttyS2"; String path = "/dev/ttyS2";//指定端口 //int baudrate = Integer.decode(sp.getString("BAUDRATE", "-1")); int baudrate = 9600;//指定速率 /* Check parameters */ if ( (path.length() == 0) || (baudrate == -1)) { throw new InvalidParameterException(); } /* Open the serial port */ mSerialPort = new SerialPort(new File(path), baudrate, 0); } return mSerialPort; } public void closeSerialPort() { if (mSerialPort != null) { mSerialPort.close(); mSerialPort = null; } } }
最后别忘了一个操作权限的问题，很多设备直接操作串口，会提示无权限 read/write 的问题，需要java层去提权，方法如下：
使用下面的方法执行指令： chmod 777 /dev/ttyS2
public void exeShell(String cmd){ try{ Process p = Runtime.getRuntime().exec(cmd); BufferedReader in = new BufferedReader( new InputStreamReader( p.getInputStream())); String line = null; while ((line = in.readLine()) != null) { Log.i("exeShell",line); } } catch(Throwable t) { t.printStackTrace(); } }
手动解决方法：打开cmd，进入 adb shell，执行：chmod 777 /dev/ttyS2
参考：
https://code.google.com/p/android-serialport-api/
https://github.com/cepr/android-serialport-api
http://blog.csdn.net/imyang2007/article/details/8331800
http://blog.csdn.net/imyang2007/article/details/8331800
http://bbs.csdn.net/topics/380234030
