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因此，我正在编写一个应用程序，用于读取串口读取数据。这些数据来自与力传感器相连的arduino--实质上，应用程序旨在衡量某物的重量。我在这里找到串口代码：https://www.allaboutcircuits.com/projects/communicate-with-your-arduino-through-android/，我在多种不同的活动中使用它（因为我需要校准活动，实际测量活动等）。我的问题是，同一个确切的串行端口代码在一个活动中工作，并且不在另一个活动中工作。它工作在这个活动中，例如：相同的代码在不同的Android活动中运行方式不同
public class EnterDataActivity extends AppCompatActivity {
private static final long TIMER_DELAY = 5000;
private static final long TIMER_LENGTH = 15000;
EditText enterMax, enterMin;
Button submitMax, submitMin, continueButton;
Chronometer emptyBagTimer;
boolean firstMeasure, getEmptyBagData, canEnterMax, canEnterMin;
ArrayList<String> emptyBagData;
float maxLoad, minLoad;
// serial port variables:
public final String ACTION_USB_PERMISSION = "com.example.jake.USB_PERMISSION";
UsbManager usbManager;
UsbDevice device;
UsbSerialDevice serialPort;
UsbDeviceConnection connection;
UsbSerialInterface.UsbReadCallback mCallback = new UsbSerialInterface.UsbReadCallback() { //Defining a Callback which triggers whenever data is read.
@Override
public void onReceivedData(byte[] arg0) {
String data;
try {
data = new String(arg0, "UTF-8");
if(getEmptyBagData)
emptyBagData.add(data);
} catch (UnsupportedEncodingException e) {}
}
};
private final BroadcastReceiver broadcastReceiver = new BroadcastReceiver() { //Broadcast Receiver to automatically start and stop the Serial connection.
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(ACTION_USB_PERMISSION)) {
boolean granted = intent.getExtras().getBoolean(UsbManager.EXTRA_PERMISSION_GRANTED);
if (granted) {
connection = usbManager.openDevice(device);
serialPort = UsbSerialDevice.createUsbSerialDevice(device, connection);
if (serialPort != null) {
if (serialPort.open()) { //Set Serial Connection Parameters.
serialPort.setBaudRate(9600);
serialPort.setDataBits(UsbSerialInterface.DATA_BITS_8);
serialPort.setStopBits(UsbSerialInterface.STOP_BITS_1);
serialPort.setParity(UsbSerialInterface.PARITY_NONE);
serialPort.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);
serialPort.read(mCallback);
} else {
Log.d("SERIAL", "PORT NOT OPEN");
}
} else {
Log.d("SERIAL", "PORT IS NULL");
}
} else {
Log.d("SERIAL", "PERM NOT GRANTED");
}
} else if (intent.getAction().equals(UsbManager.ACTION_USB_DEVICE_ATTACHED)) {
start();
} else if (intent.getAction().equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {
stop();
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_enter_data);
usbManager = (UsbManager) getSystemService(USB_SERVICE);
IntentFilter filter = new IntentFilter();
filter.addAction(ACTION_USB_PERMISSION);
filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
registerReceiver(broadcastReceiver, filter);
enterMax = (EditText) findViewById(R.id.enterMax);
enterMin = (EditText) findViewById(R.id.enterMin);
submitMax = (Button) findViewById(R.id.submitMax);
submitMin = (Button) findViewById(R.id.submitMin);
continueButton = (Button) findViewById(R.id.continueButton);
emptyBagTimer = (Chronometer) findViewById(R.id.emptyBagTimer);
firstMeasure = true;
getEmptyBagData = false;
canEnterMax = true;
canEnterMin = true;
emptyBagData = new ArrayList<>();
start();
}
// method: measureEmptyBag
// description: this method is called when the button to measure the mass of the empty bag is
// pressed. It starts the chronometer and serial port, first waiting TIMER_DELAY milliseconds
// from the button press, then sets a boolean to true that causes the serial data to be added to
// an arraylist over the next TIMER_LENGTH milliseconds. It then sets the next views in the
// enter data process to visible. The firstMeasure boolean is to prevent spamming.
public void measureEmptyBag(View view){
if(firstMeasure) {
firstMeasure = false;
start();
emptyBagTimer.setBase(SystemClock.elapsedRealtime());
emptyBagTimer.start();
emptyBagTimer.setFormat("Waiting - %s");
emptyBagTimer.setOnChronometerTickListener(new Chronometer.OnChronometerTickListener() {
@Override
public void onChronometerTick(Chronometer chronometer) {
if (SystemClock.elapsedRealtime() - emptyBagTimer.getBase() <= TIMER_DELAY)
emptyBagTimer.setFormat("Waiting - %s");
else if (SystemClock.elapsedRealtime() - emptyBagTimer.getBase() <= TIMER_DELAY + TIMER_LENGTH) {
emptyBagTimer.setFormat("Calculating - %s");
getEmptyBagData = true;
}
else if (SystemClock.elapsedRealtime() - emptyBagTimer.getBase() > TIMER_DELAY + TIMER_LENGTH) {
getEmptyBagData = false;
emptyBagTimer.stop();
enterMax.setVisibility(View.VISIBLE);
submitMax.setVisibility(View.VISIBLE);
}
else
emptyBagTimer.setFormat("Waiting - %s");
}
});
}
}
// method: setMaxLoad
// description: called when the submit button is pressed for the max load, this method trys to
// pull the max load value from it edit text and store it. If that is successful (the user has
// entered in a number) then it sets the next views in the enter data process to visible.
public void setMaxLoad(View view){
if(canEnterMax){
try {
canEnterMax = false;
maxLoad = Float.parseFloat(enterMax.getText().toString());
enterMin.setVisibility(View.VISIBLE);
submitMin.setVisibility(View.VISIBLE);
} catch (Exception e) {} // in case the user enters a non number
}
}
// method: setMinLoad
// description: called when the submit button is pressed for the min load, this method trys to
// pull the min load value from its edit text and store it. If that is successful (the user has
// entered in a number) then it sets the next view in the enter data process to visible.
public void setMinLoad(View view){
if(canEnterMin){
try {
canEnterMin = false;
minLoad = Float.parseFloat(enterMin.getText().toString());
continueButton.setVisibility(View.VISIBLE);
} catch (Exception e) {} // in case the user enters a non number
}
}
// method: continuePressed
// description: this method is called when the continue button is pressed. It averages all of the
// data read in over the measure empty mass period to find the mass when empty, then writes that
// value along with maxLoad and minLoad to a file for later use. Finally it starts the pump
// activity
public void continuePressed(View view){
int emptyMassSum = 0;
int emptyMass;
// cleaning up emptyBagData to only include 3,2, or 1 digit numbers (the serial output gets
// wonky sometimes and spits out weird numbers that would throw off the calculations below,
// so those numbers need to be removed)
for (int i = emptyBagData.size() - 1; i >= 0; i--)
if (emptyBagData.get(i).length() != 3)
emptyBagData.remove(i);
// add up all the values in emptyBagData (try catch in case a non-number was read in)
for (int i = emptyBagData.size() - 1; i >= 0; i--) {
try {
emptyMassSum += Integer.parseInt(emptyBagData.get(i));
} catch (Exception e) {
emptyBagData.remove(i);
}
}
emptyMass = emptyMassSum/emptyBagData.size();
FileOutputStream outputStream;
String dataOut = "E" + emptyMass + "Mx" + maxLoad + "Mn" + minLoad + ";";
try {
outputStream = openFileOutput("BagData.txt", Context.MODE_PRIVATE);
outputStream.write(dataOut.getBytes());
outputStream.close();
} catch (Exception e) {
continueButton.setText(R.string.file_write_error_message);
}
Intent intent = new Intent(this, PumpActivity.class);
startActivity(intent);
}
// serial port methods:
public void start() {
HashMap<String, UsbDevice> usbDevices = usbManager.getDeviceList();
if (!usbDevices.isEmpty()) {
boolean keep = true;
for (Map.Entry<String, UsbDevice> entry : usbDevices.entrySet()) {
device = entry.getValue();
int deviceVID = device.getVendorId();
if (deviceVID == 10755 || deviceVID == 9025)//Arduino Vendor ID
{
PendingIntent pi = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
usbManager.requestPermission(device, pi);
keep = false;
} else {
connection = null;
device = null;
}
if (!keep)
break;
}
}
}
public void stop() {
if(serialPort!=null)
serialPort.close();
}
}
通过“它的工作原理”，我的意思是我可以从串行端口进来的数据，并使用它。然而，同样的代码不能在这里工作：
public class PumpActivity extends AppCompatActivity {
File calibrationData, bagData;
int mass1, mass2, read1, read2, emptyMassNum;
float maxLoad, minLoad;
double slope, currentMassVal, emptyMass;
boolean status, runTimer;
TextView statusTextView, currentMassTextView;
Button stop;
Thread updateMass;
ArrayList<String> inData;
// this does two things when the handleMessage method is called:
// 1) it takes the most recent data read in and calculates the current mass from it, then updates
// the current mass text view to reflect that
// 2) it takes that newly calculated mass and sees if status should change, depending on how much
// mass there currently is. It also writes a value to the serial port (back to the arduino)
// depending on that status. It then updates the status text view to reflect this
Handler updateMassHandler = new Handler(){
public void handleMessage(Message msg){
// mass calculation
try{currentMassVal = calculateMass(Integer.parseInt(inData.get(inData.size()-1)));} catch (Exception e){} // try-catch in case data isn't an int
inData.clear();
currentMassTextView.setText(String.format(getResources().getString(R.string.current_mass_string), currentMassVal));
// status check with new mass
if (currentMassVal >= maxLoad)
status = true;
else if (currentMassVal <= minLoad)
status = false;
statusTextView.setText(String.format(getResources().getString(R.string.pump_status), getStatus()));
// writing back to arduino
if (serialPort != null) {
if (status)
serialPort.write("1".getBytes());
else
serialPort.write("0".getBytes());
}
}
};
// serial port variables:
public final String ACTION_USB_PERMISSION = "com.example.jake.USB_PERMISSION";
UsbManager usbManager;
UsbDevice device;
UsbSerialDevice serialPort;
UsbDeviceConnection connection;
UsbSerialInterface.UsbReadCallback mCallback = new UsbSerialInterface.UsbReadCallback() { //Defining a Callback which triggers whenever data is read.
@Override
public void onReceivedData(byte[] arg0) {
String data;
try {
data = new String(arg0, "UTF-8");
inData.add(data);
} catch (UnsupportedEncodingException e) {}
}
};
private final BroadcastReceiver broadcastReceiver = new BroadcastReceiver() { //Broadcast Receiver to automatically start and stop the Serial connection.
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(ACTION_USB_PERMISSION)) {
boolean granted = intent.getExtras().getBoolean(UsbManager.EXTRA_PERMISSION_GRANTED);
if (granted) {
connection = usbManager.openDevice(device);
serialPort = UsbSerialDevice.createUsbSerialDevice(device, connection);
if (serialPort != null) {
if (serialPort.open()) { //Set Serial Connection Parameters.
serialPort.setBaudRate(9600);
serialPort.setDataBits(UsbSerialInterface.DATA_BITS_8);
serialPort.setStopBits(UsbSerialInterface.STOP_BITS_1);
serialPort.setParity(UsbSerialInterface.PARITY_NONE);
serialPort.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);
serialPort.read(mCallback);
} else {
Log.d("SERIAL", "PORT NOT OPEN");
}
} else {
Log.d("SERIAL", "PORT IS NULL");
}
} else {
Log.d("SERIAL", "PERM NOT GRANTED");
}
} else if (intent.getAction().equals(UsbManager.ACTION_USB_DEVICE_ATTACHED)) {
start();
} else if (intent.getAction().equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {
stop();
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pump);
usbManager = (UsbManager) getSystemService(USB_SERVICE);
IntentFilter filter = new IntentFilter();
filter.addAction(ACTION_USB_PERMISSION);
filter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
registerReceiver(broadcastReceiver, filter);
status = false;
statusTextView = (TextView) findViewById(R.id.statusTextView);
statusTextView.setText(String.format(getResources().getString(R.string.pump_status), getStatus()));
currentMassTextView = (TextView) findViewById(R.id.currentMassTextView);
currentMassTextView.setText(R.string.calculating_text);
stop = (Button) findViewById(R.id.stopButton);
runTimer = true;
currentMassVal = 0;
inData = new ArrayList<>();
// thread that "calls" the handleMessage method in the upDateMassHandler every 100 milliseconds
updateMass = new Thread(new Runnable() {
@Override
public void run() {
while(runTimer){
updateMassHandler.sendEmptyMessage(0);
try{Thread.sleep(100);} catch (InterruptedException e){}
}
}
});
// thanks to stackOverflow for the file reading code
// reading and parsing from calibration data
calibrationData = new File(getFilesDir(), "CalibrationData.txt");
StringBuilder text = new StringBuilder();
// reading in the calibration data from the file (of the same name)
try {
BufferedReader br = new BufferedReader(new FileReader(calibrationData));
String line;
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
}
br.close();
} catch (IOException e) {}
// parsing values from calibration data
String calibData = text.toString();
calibData = calibData.substring(3);
mass1 = Integer.parseInt(calibData.substring(0, calibData.indexOf('R')));
calibData = calibData.substring(calibData.indexOf(':') + 1);
read1 = Integer.parseInt(calibData.substring(0, calibData.indexOf('M')));
calibData = calibData.substring(calibData.indexOf(':') + 1);
mass2 = Integer.parseInt(calibData.substring(0, calibData.indexOf('R')));
calibData = calibData.substring(calibData.indexOf(':') + 1);
read2 = Integer.parseInt(calibData.substring(0, calibData.indexOf('.')));
slope = ((double) (mass2 - mass1)/(read2 - read1)); // calculating slope of masses and reads to allow
// calculation of mass of an unknown read
// reading and parsing from bag data
bagData = new File(getFilesDir(), "BagData.txt");
StringBuilder text2 = new StringBuilder();
// reading in the bag data from the file (of the same name)
try {
BufferedReader br = new BufferedReader(new FileReader(bagData));
String line;
while ((line = br.readLine()) != null) {
text2.append(line);
text2.append('\n');
}
br.close();
} catch (IOException e) {}
// parsing values frm bag data
String bagData = text2.toString();
bagData = bagData.substring(1);
emptyMassNum = Integer.parseInt(bagData.substring(0, bagData.indexOf('M')));
bagData = bagData.substring(bagData.indexOf('x') + 1);
maxLoad = Float.parseFloat(bagData.substring(0, bagData.indexOf('M')));
bagData = bagData.substring(bagData.indexOf('n') + 1);
minLoad = Float.parseFloat(bagData.substring(0, bagData.indexOf(';')));
emptyMass = calculateMass(emptyMassNum); // emptyMassNum is the values read in from the arduino
// this converts it to a mass
updateMass.start();
start();
}
// method: calculateMass
// description: calculates the mass of the object on the transducer based off of the value read
// in and the data gotten from calibration
// input: int readVal - the value read in
// output: double - the calculated mass
public double calculateMass(int readVal){
return (slope * (readVal-read1)) + mass1;
}
// method: getStatus
// description: returns a string representation of the status
public String getStatus(){
if(status)
return "running";
else
return "stopped";
}
// method: stop
// description: stops everything when the stop button is pressed
public void stop(View view){
status = false;
runTimer = false;
stop();
stop.setText(R.string.button_stopped);
}
// serial port methods:
public void start() {
HashMap<String, UsbDevice> usbDevices = usbManager.getDeviceList();
if (!usbDevices.isEmpty()) {
boolean keep = true;
for (Map.Entry<String, UsbDevice> entry : usbDevices.entrySet()) {
device = entry.getValue();
int deviceVID = device.getVendorId();
if (deviceVID == 10755 || deviceVID == 9025)//Arduino Vendor ID
{
PendingIntent pi = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
usbManager.requestPermission(device, pi);
keep = false;
} else {
connection = null;
device = null;
}
if (!keep)
break;
}
}
}
public void stop() {
if(serialPort!=null)
serialPort.close();
}
}
出于某种原因，在mCallback变量onReceivedData方法似乎并没有在第二个活动（一不工作）被调用。我很确定这是问题，我只是不确定为什么它被称为一个活动，而不是另一个具有相同的代码。如果该方法未被调用，那么我无法访问进入的数据，这是我的问题。
任何和所有的帮助将不胜感激！
老兄这是一个问题，太多的代码。 –