Android 串口通信

前段时间项目里用到了android的串口通信，网上查找资料，找到了下面一篇文章

http://lpcjrflsa.iteye.com/blog/2097280

我参考这篇文章实现了串口通信，在这里记录一下，省得以后再看的时候找不到。还有几点说明一下

1、原文使用eclipse，将android-serialport-api源码里的两个文件复制进工程里。我是用android studio，将源码直接导入到android studio里，再将app文件夹作为库添加进新项目里，具体方法前面博客已经说过了，不再赘述。

2、项目里需要android通过串口给单片机发送十六进制的指令，所以添加了hexStringToBytes（）这个方法，将String类型以十六进制发送。

3、接收数据改用线程

下面是完整代码：
MainActivity.java

package com.example.administrator.serialporttest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import android_serialport_api.SerialPort;

public class MainActivity extends AppCompatActivity {
    private Button btn_open, btn_send, btn_rec;
    private EditText edRec;

    private FileOutputStream mOutputStream;
    private FileInputStream mInputStream;
    private SerialPort sp;

    private ReadThread mReadThread;

    private class ReadThread extends Thread {//接收线程
        @Override
        public void run() {
            super.run();
            while (!isInterrupted()) {
                int size;
                try {
                    byte[] buffer = new byte[64];
                    if (mInputStream == null) return;
                    size = mInputStream.read(buffer);//接收数据
                    if (size > 0) {
                        onDataReceived(buffer, size);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                    return;
                }
            }
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        edRec = (EditText) findViewById(R.id.edRec);

        btn_open = (Button) findViewById(R.id.open);
        btn_open.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    sp = new SerialPort(new File("/dev/ttySAC3"), 19200, 0);//这里写你要打开的串口和波特率
                    Toast.makeText(getApplicationContext(), "open",
                            Toast.LENGTH_SHORT).show();
                } catch (SecurityException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                mOutputStream = (FileOutputStream) sp.getOutputStream();
                mInputStream = (FileInputStream) sp.getInputStream();
            }
        });

        btn_send = (Button) findViewById(R.id.send);
        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
//                    mOutputStream.write(new String("send").getBytes());
                    mOutputStream.write(hexStringToBytes("AA01BB"));//这里发送的是十六进制的数据
                    Toast.makeText(getApplicationContext(), "send",
                            Toast.LENGTH_SHORT).show();
                } catch (IOException e) {
                    e.printStackTrace();
                }


            }
        });

        btn_rec = (Button) findViewById(R.id.rec);
        btn_rec.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                mReadThread = new ReadThread();
                mReadThread.start();
            }
        });
    }

    void onDataReceived(final byte[] buffer, final int size) {
        runOnUiThread(new Runnable() {
            public void run() {
                if (edRec != null) {
                    edRec.append(new String(buffer, 0, size));

                }
            }
        });
    }

    public static byte[] hexStringToBytes(String inputStr) {
        byte[] result = new byte[inputStr.length() / 2];
        for (int i = 0; i < inputStr.length() / 2; ++i)
            result[i] = (byte) (Integer.parseInt(inputStr.substring(i * 2, i * 2 + 2), 16) & 0xff);
        return result;
    }

    @Override
    protected void onDestroy() {
        if (mReadThread != null)
            mReadThread.interrupt();
        sp = null;
        super.onDestroy();
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.administrator.serialporttest.MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/open"
        android:text="open"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/send"
        android:text="send"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/rec"
        android:text="rec"/>
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/edRec"/>
    </LinearLayout>
</LinearLayout>

界面设计和原文差不多，我就不放图了

下面是完整项目地址

http://download.youkuaiyun.com/detail/amazinguu/9630474

P.S:附上一个bytesToHexString（）方法，可以用来处理android通过串口接收单片机发送的十六进制数据

public static String bytesToHexString(byte[] buffer){
        String result="";
        for (int i = 0; i < buffer.length; i++) {
            String hex = Integer.toHexString(buffer[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            result=result+hex;//result字符串长度为2的倍数
        }
        return result;
    }