android開發(37) android使用android_serialport_api 操作串口,解決權限問題


最近有個項目,要使用android設備操作串口的 斑馬GK888T打印機,使用打印機打印二維碼。

 

硬件設備連接方式:

安卓設備 通過 串口RS232 連接 斑馬打印機的串口

 

那么就要解決:使用安卓設備操作串口的問題。 我找到一個框架:android_serialport_api,這個框架被托管在:

https://code.google.com/p/android-serialport-api/    谷歌的代碼庫,無奈國內無法下載

https://github.com/cepr/android-serialport-api     GITHUB的地址,這個可以下載

下載后,閱讀下源代碼,准備使用。

 

1.拷貝 jni 文件夾下的文件到 你的project中, 這些是jni調用的設定文件,包括:

  Android.mk

  Application.mk

  gen_SerialPort_h.sh

  SerialPort.c

  SerialPort.h

2.拷貝libs 下的文件到你的 project中,這些是原生庫,包括

  armeabi/libserial_port.so

  armeabi-v7a/libserial_port.so

  x86/libserial_port.so

3.在你的項目下新建 package: android_serialport_api,拷貝下列src下的class  到這個package下

  Application.java

  SerialPort.java

  SerialPortActivity.java

  SerialPortFinder.java

  注意, package名稱一定要是android_serialport_api。或者你需要修改Android.mk下對應的模塊配置項。不然會提示找不到jni調用的庫

4.拷貝資源文件等:

  string.xml 的內容:

    <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節點指定對應的 "android:name" 配置,如下面紅色文字所示

    <application
        android:allowBackup="true"
        android:name="android_serialport_api.Application"
        android:theme="@style/AppTheme" >

6.下面寫測試的activity。我的設備連接在安卓設備的端口 ”ttyS2”上,下面是個演示:

<?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();
                }
            }
        });
        //發送指令到斑馬打印機
        mEmission.setText("^XA^A0N,40,30^FO50,150^FDHELLO WORLD^FS^XZ");
    /*二維碼指令

      ^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;
        }
    }
}

 

 

最后別忘了一個操作權限的問題,很多設備直接操作串口,會提示無權限 read/write 的問題,需要java層去提權,方法如下:

使用下面的方法執行指令: 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(); } }

手動解決方法:打開cmd,進入  adb shell,執行:chmod 777 /dev/ttyS2

 

 

 參考:

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


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