Android USB转ttl串口
讲到USB转串口，大都是用的USB->ttl模块，我手里这个是USB CH340的一个usb转串口模块,具体长什么样子可以百度搜一下，这种串口的实现方式和谷歌提供的那种串口解决方式不通，这种是通过USB传输数据的，实现起来比较简单一些，下面来看一下方法：
1、需要用到的jar包 CH34xUARTDriver.jar
链接：https://pan.baidu.com/s/14QHOf_-4jK03u687lCRWIw
提取码：yjhk
2、AndroidManifest.xml配置USB权限
3、在当前的activity下添加
4、在Application 里实现一个静态的CH34xUARTDriver 对象
public class MyApp extends Application {
public static CH34xUARTDriver driver;
}
5、在activity内实现串口读写开关
public class MainActivity extends Activity {
private static final String ACTION_USB_PERMISSION = "cn.wch.wchusbdriver.USB_PERMISSION";
private EditText readText;
private boolean isOpen;
private Handler handler;
private int retval;
private MainActivity activity;
public byte[] writeBuffer;
public byte[] readBuffer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyApp.driver = new CH34xUARTDriver(
(UsbManager) getSystemService(Context.USB_SERVICE), this,
ACTION_USB_PERMISSION);
initUI();
//判断系统是否支持USB HOST
if (!MyApp.driver.UsbFeatureSupported()) {
Dialog dialog = new AlertDialog.Builder(MainActivity.this)
.setTitle("提示")
.setMessage("您的设备不支持USBhost")
.setPositiveButton("确认",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface arg0,
int arg1) {
System.exit(0);
}
}).create();
dialog.setCanceledOnTouchOutside(false);
dialog.show();
}
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);//保持屏幕常亮状态
writeBuffer = new byte[512];
readBuffer = new byte[512];
isOpen = false;
activity = this;
//打开流程主要步骤为ResumeUsbList，UartInit
openButton.setOnClickListener(new openButton());
openButton.post(new Runnable() {
@Override
public void run() {
openButton.performClick();
}
});
handler = new Handler() {
public void handleMessage(Message msg) {
String str = msg.obj.toString();//设备回来的数据
String s0 = str.substring(0, 8);
if(s0.equals("01 03 09")){
//String s1 = str.substring(9,23); /**卡号*/
String s2 = str.substring(24,35);/**余额*/
int i = Integer.valueOf(s2.replaceAll(" ",""),16);//转换成分
String s = String.valueOf(i/100); //转换成元
synthesizer.showVideo("您的卡上余额为:"+s+"元");
}
readText.append((String) msg.obj);
}
};
}
class WriteButton implements View.OnClickListener{
@Override
public void onClick(View v) {
byte[] to_send = toByteArray(writeText.getText().toString());
int retval = MyApp.driver.WriteData(to_send, to_send.length);
//写数据，第一个参数为需要发送的字节数组，第二个参数为需要发送的字节长度，返回实际发送的字节长度
if (retval < 0){
Toast.makeText(MainActivity.this, "写失败",
Toast.LENGTH_SHORT).show();
}else {
writeBtn.setOnClickListener(new WriteBtn());
writeBtn.post(new Runnable() {
@Override
public void run() {
writeBtn.performClick();
}
});
}
}
}
class WriteBtn implements View.OnClickListener{
@Override
public void onClick(View v) {
byte[] to_send = toByteArray(write.getText().toString());
int retval = MyApp.driver.WriteData(to_send, to_send.length);
//写数据，第一个参数为需要发送的字节数组，第二个参数为需要发送的字节长度，返回实际发送的字节长度
if (retval < 0) {
Toast.makeText(MainActivity.this, "写失败",
Toast.LENGTH_SHORT).show();
}
}
}
class setButton implements View.OnClickListener{
@Override
public void onClick(View v) {
if (MyApp.driver.SetConfig((byte)9600, (byte)8, (byte)1, (byte)0,
(byte)0)) {//配置串口波特率，函数说明可参照编程手册
Toast.makeText(MainActivity.this, "串口设置成功",
Toast.LENGTH_SHORT).show();
//01 05 00 00 FF 00 8c 3a
//01 06 00 00 00 64 88 21
/*byte[] send = toByteArray(write.getText().toString());
MyApp.driver.WriteData(send, send.length);*/
writeButton.setOnClickListener(new WriteButton());
writeButton.post(new Runnable() {
@Override
public void run() {
writeButton.performClick();
}
});
} else {
Toast.makeText(MainActivity.this, "串口设置失败",
Toast.LENGTH_SHORT).show();
}
}
}
class openButton implements View.OnClickListener{
@Override
public void onClick(View v) {
if (!isOpen) {
retval = MyApp.driver.ResumeUsbList();
if (retval == -1) {// ResumeUsbList方法用于枚举CH34X设备以及打开相关设备
Toast.makeText(MainActivity.this, "打开设备失败",
Toast.LENGTH_SHORT).show();
MyApp.driver.CloseDevice();
} else if (retval == 0){
if (!MyApp.driver.UartInit()) {//对串口设备进行初始化操作
Toast.makeText(MainActivity.this, "设备初始化失败",
Toast.LENGTH_SHORT).show();
Toast.makeText(MainActivity.this, "打开" +
"设备失败",
Toast.LENGTH_SHORT).show();
return;
}
Toast.makeText(MainActivity.this, "打开设备成功",
Toast.LENGTH_SHORT).show();
isOpen = true;
openButton.setText("关闭");
configButton.setEnabled(true);
writeButton.setEnabled(true);
new readThread().start();//开启读线程读取串口接收的数据
configButton.setOnClickListener(new setButton());
configButton.post(new Runnable() {
@Override
public void run() {
configButton.performClick();
}
});
} else {
AlertDialog.Builder builder = new AlertDialog.Builder(activity);
builder.setIcon(R.drawable.icon);
builder.setTitle("未授权限");
builder.setMessage("确认退出吗？");
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
System.exit(0);
}
});
builder.setNegativeButton("返回", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
builder.show();
}
} else {
MyApp.driver.CloseDevice();
openButton.setText("打开");
configButton.setEnabled(false);
writeButton.setEnabled(false);
isOpen = false;
}
}
}
/*
* 读取设备数据
* */
private class readThread extends Thread {
public void run() {
byte[] buffer = new byte[4096];
while (true) {
Message msg = Message.obtain();
if (!isOpen) {
break;
}
int length = MyApp.driver.ReadData(buffer, 4096);
if (length > 0) {
String recv = toHexString(buffer, length);
msg.obj = recv;
handler.sendMessage(msg);
}
}
}
}
/**
* 将byte[]数组转化为String类型
* @param arg
* 需要转换的byte[]数组
* @param length
* 需要转换的数组长度
* @return 转换后的String队形
*/
private String toHexString(byte[] arg, int length) {
String result = new String();
if (arg != null) {
for (int i = 0; i < length; i++) {
result = result
+ (Integer.toHexString(
arg[i] < 0 ? arg[i] + 256 : arg[i]).length() == 1 ? "0"
+ Integer.toHexString(arg[i] < 0 ? arg[i] + 256
: arg[i])
: Integer.toHexString(arg[i] < 0 ? arg[i] + 256
: arg[i])) + " ";
}
return result;
}
return "";
}
/**
* 将String转化为byte[]数组
* @param arg
* 需要转换的String对象
* @return 转换后的byte[]数组
*/
private byte[] toByteArray(String arg) {
if (arg != null) {
char[] NewArray = new char[1000];
char[] array = arg.toCharArray();
int length = 0;
for (int i = 0; i < array.length; i++) {
if (array[i] != ' ') {
NewArray[length] = array[i];
length++;
}
}
int EvenLength = (length % 2 == 0) ? length : length + 1;
if (EvenLength != 0) {
int[] data = new int[EvenLength];
data[EvenLength - 1] = 0;
for (int i = 0; i < length; i++) {
if (NewArray[i] >= '0' && NewArray[i] <= '9') {
data[i] = NewArray[i] - '0';
} else if (NewArray[i] >= 'a' && NewArray[i] <= 'f') {
data[i] = NewArray[i] - 'a' + 10;
} else if (NewArray[i] >= 'A' && NewArray[i] <= 'F') {
data[i] = NewArray[i] - 'A' + 10;
}
}
byte[] byteArray = new byte[EvenLength / 2];
for (int i = 0; i < EvenLength / 2; i++) {
byteArray[i] = (byte) (data[i * 2] * 16 + data[i * 2 + 1]);
}
return byteArray;
}
}
return new byte[] {};
}
/**
* 将String转化为byte[]数组
* @param arg
* 需要转换的String对象
* @return 转换后的byte[]数组
*/
private byte[] toByteArray2(String arg) {
if (arg != null) {
char[] NewArray = new char[1000];
char[] array = arg.toCharArray();
int length = 0;
for (int i = 0; i < array.length; i++) {
if (array[i] != ' ') {
NewArray[length] = array[i];
length++;
}
}
NewArray[length] = 0x0D;
NewArray[length + 1] = 0x0A;
length += 2;
byte[] byteArray = new byte[length];
for (int i = 0; i < length; i++) {
byteArray[i] = (byte)NewArray[i];
}
return byteArray;
}
return new byte[] {};
}
}