W1ll's questions

I am trying to implement a sketch using a esp8266 como servidor, I need to send a string to the client and for that I am using this piece of code:

  char sbuf[] = "Hello world!\n\r";
  size_t len = strlen(sbuf);
  for (i = 0; i < MAXCLIENTS; i++) {
  if (serverClients[i] && serverClients[i].connected()) {
    serverClients[i].write((char*) &sbuf, len);
    delay(1);
  }
}

Everything funciona OKand the client can receive the characters, now I want to do una funcionthis so I can call it when I need it, so I have tried to implement my function:

void sendDataToClient( char *sbuf[]) {
size_t len = strlen(sbuf) + 1;
for (i = 0; i < MAXCLIENTS; i++) {
 if (serverClients[i] && serverClients[i].connected()) {
   serverClients[i].write((char*) &sbuf, len);
   delay(1);
  }
 }
}

and so I am llamando a la funcion:

char bufferMSGtoClient[] = "Hello world!\n\r\0";

sendDataToClient(bufferMSGtoClient);

But this no funcion, the client does not receive anything, could someone tell me what myerror?

I am getting gps readings using these lines of code:

String mLatitud = String.valueOf(location.getLatitude());
String mLongitud = String.valueOf(location.getLongitude());

The problem is that in some occasions the amount of decimals varia de 6 a 15 decimales, I need that latitud tenga 6 decimalesand longitud 5 decimales.

How can I do that?

I have a conflict that causes my device to hang when I put both read gps and phone number permissions in a single activity, but when I test the permissions in two different activities everything works fine.

Here is part of the permissions in the manifest:

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

Here the MainActivity:

public class MainActivity extends AppCompatActivity {
TextView tvMensaje;
String mPhoneNumber;
private static final long MIN_TIME = 10000; // 10 segundos Minimo tiempo para updates en Milisegundos
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvMensaje = findViewById(R.id.tvMensaje);
    //*     Permission to Read PhoneNumber
    if (ActivityCompat.checkSelfPermission(this, READ_SMS) == PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(this, READ_PHONE_NUMBERS)
            == PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(this,READ_PHONE_STATE)
            == PackageManager.PERMISSION_GRANTED) {
        TelephonyManager tMgr = (TelephonyManager)   this.getSystemService(Context.TELEPHONY_SERVICE);
        String mPhoneNumber = tMgr.getLine1Number();
        return;
    } else {
        requestPermission();
     }

    //*     Permission to Read GPS
    if(ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION,}, 1000);
    } else {
        iniciarLocalizacion();
    }
}

private void iniciarLocalizacion() {

    if(ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED
            && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {

        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION,}, 1000);
        return;
    }

    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME, 0, local);
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME, 0, local);

    tvMensaje.setText("Inicializando GPS");
}

private void requestPermission() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        requestPermissions(new String[]{READ_SMS, READ_PHONE_NUMBERS, READ_PHONE_STATE}, 100);
    }
}
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case 100:
            TelephonyManager tMgr = (TelephonyManager)  this.getSystemService(Context.TELEPHONY_SERVICE);
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,Manifest.permission.READ_PHONE_NUMBERS) != PackageManager.PERMISSION_GRANTED  && ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) !=      PackageManager.PERMISSION_GRANTED) {
                return;
            }
            String mPhoneNumber = tMgr.getLine1Number();
            Log.e( "DEBUG-->", "Nro: " + mPhoneNumber );
            break;

        case 1000:
            if(grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                iniciarLocalizacion();
                return;
            }
            break;
      }
   }
}

Here part of the logcat:

Can you tell me what is my mistake?

I need to convert a string arrayto pares hexadecimalesfor each byte, zero separating each pair and completados con ceros a la izquierdaif necessary.

Using my code I get this:

41 54 2B 43 53 51 C A

But I need this:

41 54 2B 43 53 51 0C 0A

This is my code:

 public class StringToHex {

    public String convertStringToHex(String str) {

        char[] chars = str.toCharArray();

        StringBuffer hex = new StringBuffer();
        for (int i = 0; i < chars.length; i++) {
            hex.append( Integer.toHexString( (int)  chars[i]).toUpperCase());
            if (hex.length() < 2) {
                hex.insert(1, '0');
            }
            hex.append(" ");
        }
        return hex.toString();
    }
}

But it doesn't seem to work, can you tell me what is my mistake?

I need to change the texto de un botonaccording to certain conditions, but this inside a Fragment, but when I try to do it I have an error here:

mHexBtn.setText(modoConsola);

Could someone tell me how to correct this.

Here is my code:

private boolean mConfigModeConsola;
private String modoConsola = "";

public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.content_main, container, false);

    mSendText = view.findViewById(R.id.send_text);
    mHexBtn = (Button) view.findViewById(R.id.hex_btn);

    mHexBtn.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v) {
            if(mConfigModeConsola == false) {
                mConfigModeConsola = true;
                modoConsola = "HEX";
                mHexBtn.setText(modoConsola);
                mSendText.setText( "" );
             }
            else {
                mConfigModeConsola = false;
                modoConsola = "ASCII";
                mHexBtn.setText(modoConsola);
                mSendText.setText( "" );
            }
        }
    });

    return view;
}

Here the error:

In my code I need to implement a setOnClickListenerbut inside a Fragmentbut when I try to do it I get an error The setOnClickListener symbol cannot be resolved , could someone tell me how to correct this?

Here is my code:

public class TerminalFragment extends Fragment implements ServiceConnection, SerialListener {
.
.   
mHexBtn.setOnClickListener(new View.OnClickListener(){
    public void onClick(View v) {
    .
    .
    }
});

I need to place the date as título de un Listviewbut inside a bubble, could someone tell me how to do it.

Here is the code to put thefecha como título:

    readFechaActual();
    TextView textView = new TextView(context);
    textView.setText(stringDate);
    listView.addHeaderView(textView);

With this code I get this:

But what I need is a title like this:

Here the file to create the bubble: drawable/time_message.xml:

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="@color/SALMON" />
<corners android:radius="20dp" />

I have this code in my app, but I don't understand how it is evaluated: return chatBubble.myMessage() ? 1 : 0;,

Could someone tell me how is this?

    public int getItemViewType(int position) {
    ChatBubble chatBubble = messages.get(position);
    return chatBubble.myMessage() ? 1 : 0;
}

I am using this BroadcastReceiver to monitor if the WIFI is connected or disconnected , but it is not working for me, it detects that the WIFI is connected but not when it is disconnected, can someone tell me what is the error?

public class MainActivity extends Activity {

private BroadcastReceiver WifiReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        int WifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
                WifiManager.WIFI_STATE_UNKNOWN);

        switch (WifiState) {
            case WifiManager.WIFI_STATE_ENABLED: {
                Toast.makeText(context,"Wifi enabled",Toast.LENGTH_LONG).show();
            }
            break;

            case WifiManager.WIFI_STATE_ENABLING: {
                Toast.makeText(context,"Wifi enabling",Toast.LENGTH_LONG).show();
            }
            break;
            case WifiManager.WIFI_STATE_DISABLED: {
                Toast.makeText(context,"Wifi disabled",Toast.LENGTH_LONG).show();
            }
            break;

            case WifiManager.WIFI_STATE_DISABLING: {
            }
            break;

            case WifiManager.WIFI_STATE_UNKNOWN: {
            }
            break;
        }
    } };

protected void onResume(){
    super.onResume();
    registerReceiver(WifiReceiver, new IntentFilter( WifiManager.WIFI_STATE_CHANGED_ACTION));
}

protected void onPause(){
    super.onPause();
    unregisterReceiver(WifiReceiver);
}

}

In my application I am using EditTextPreference to request the user to enter an IP address, but in the XML file the initial value is defaultValue="192.168.1.0" and it has a light blue background as you can see in the image, I need to change the color only of this initial text and the background, can someone tell me how to do it in the XML?

    <EditTextPreference
      android:defaultValue="192.168.1.0"
      android:digits="0123456789."
      android:inputType="number|numberDecimal"
      android:key="example_text"
      android:maxLines="1"
      android:selectAllOnFocus="true"
      android:singleLine="true"
      android:title="IP Address" />

I am using this code so that it only accepts IP addresses in the EditText, but I would like that if I enter more than three digits it will automatically insert the period, could someone tell me how to do this?

InputFilter[] filters = new InputFilter[1];
    filters[0] = new InputFilter() {
        @Override
        public CharSequence filter(CharSequence source, int start, int end,android.text.Spanned dest, int dstart, int dend) {
            if (end > start) {
                String destTxt = dest.toString();
                String resultingTxt = destTxt.substring( 0, dstart ) + source.subSequence( start, end ) + destTxt.substring( dend );
                if (!resultingTxt.matches( "^\\d{1,3}(\\.(\\d{1,3}(\\.(\\d{1,3}(\\.(\\d{1,3})?)?)?)?)?)?" )) {
                    return "";
                } else {
                    String[] splits = resultingTxt.split( "\\." );
                    for (int i = 0; i < splits.length; i++) {
                        if (Integer.valueOf( splits[i] ) > 255) {
                            return "";
                        }
                    }
                }
            }
            return null;
        }
    };
    ipAddress.setFilters( filters );

When I start my app in Android it works fine but when I try to put this app in the background I get the following error:

This is what I have in the MainActivity:

public class MainActivity extends AppCompatActivity...
.
.
@Override
protected void onPause() {
    super.onPause();
    mTcpClient.stopClient();
    mTcpClient = null;
    mTcpClient.stopClient();

    arrayList.clear();
    mAdapter.notifyDataSetChanged();
}

And this is what I have in the TcpClient class:

public class TcpClient {
.
.
public void stopClient() {

    statusWIFIX = false;
    Log.e( "DEBUG-->", "Coneccion Cerrada: "+ statusWIFIX );
    sendMessage(Constants.CLOSED_CONNECTION+": " + Modelox);                
// send message that we are closing the connection
    mRun = false;
    if (mBufferOut != null) {
        mBufferOut.flush();
        mBufferOut.close();
    }
    mMessageListener = null;
    mBufferIn = null;
    mBufferOut = null;
    mServerMessage = null;
}

Can someone tell me how to correct this?

In the MainActivity I need to implement a listener, which can receive data (boolean statusWIFIX) sent by TcpClient, The TcpClient class is being used in MainActivity, that is, it is instantiated there,

This is my code of my TcpClient:

public class TcpClient {
.
.
public Boolean statusWIFIX = false;
private TcpListener1 mTcpListener1;
public TcpClient(TcpListener1 tcpListener1) {mTcpListener1 = tcpListener1;}

interface TcpListener1 {
    void onReportStatusWIFIX(boolean statusWIFIX);
}

public void stopClient() {

    statusWIFIX = false;
    // Report status to listener (MainActivity)
    mTcpListener1.onReportStatusWIFIX(statusWIFIX);

    Log.e( "DEBUG-->", "Coneccion Cerrada: "+ statusWIFIX );
    sendMessage(Constants.CLOSED_CONNECTION+": " + Modelox);                // send message that we are closing the connection
}
.
.

And this is the code of my MainActivity, where it evaluated the value of statusWIFI which I will use to hide or make visible an icon on the upper screen:

public class MainActivity extends AppCompatActivity implements 
NavigationView.OnNavigationItemSelectedListener {
...
private TcpClient mTcpClient;

private TcpClient.TcpListener1 mTcpListener1 = new TcpClient.TcpListener1() 
{
    @Override
    void onReportStatusWIFIX(boolean statusWIFIX) {
        if (statusWIFIX == true) {
            statusWIFI = true;
        }else{statusWIFI = false;
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_main );

    mTcpClient = new TcpClient(mTcpListener1);
...
}
...
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
MenuItem IconWIFI = menu.findItem(R.id.bt1_wifi);

if (statusWIFI == true){
    IconWIFI.setVisible(true);
}
if (statusWIFI == false){
    IconWIFI.setVisible(false);
}
return super.onPrepareOptionsMenu(menu);
}
... 
}

But I have this error, could someone tell me how to correct it.

I am making an app that sends and receives data and this data is displayed in one ListViewbut I would like to change the color of the text so that the received texts (RX...) are colored and the texts (TX...) are of a different color, can this be done? What?.

Here is my code, I have tried to use Html.fromHtmlbut it doesn't work.

//* Aqui Transmite datos
send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
    String message = editText.getText().toString();
    arrayList.add("TX: " + message);                        
    //arrayList.add( Html.fromHtml( redB +  "TX: " + message + colorEnd ) );
    if (mTcpClient != null) {
        mTcpClient.sendMessage(message);                    
    }
    mAdapter.notifyDataSetChanged();                        
    editText.setText("");
  }
});
.
.

//* Aqui Recibe datos
@Override
   protected void onProgressUpdate(String... values) {
   super.onProgressUpdate(values);
   arrayList.add("RX: " + values[0]);                
   mAdapter.notifyDataSetChanged();                  
}

I am making an app in which I am trying to create the "Download/Datax" directory and write txt files to the external SD memory and I am using this code:

File directorioExt = new File( Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_DOCUMENTS ), "/Download/Datax/" );
if (!directorioExt.exists()) {
   File directoriox = new File( Environment.getExternalStorageDirectory() + "/Download/Datax/" );
   directoriox.mkdirs();
   }

But the directory cannot be created in external memory. I have also placed in the manifest:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Can someone tell me how to achieve this?

It seems that I have a conflict between PreferenceFragment and onOptionsItemSelected , I am trying to send several ListPreference variables from UsbSettingActivity to the MainActivity using Intents, the problem is that I only get the first data, using the SDK debug in this activity, it observed that only the first data is available. fact:

mconfigbaudrate = 9600

Here is my code

public class UsbSettingActivity extends AppCompatPreferenceActivity {

final String setBaudRate = "" ;
public static String mconfigbaudrate = "";
public static String mconfigdatabit = "";
public static String mconfigbitstop = "";
public static String mconfigparity = "";
public static String mconfigfontsize = "";
public static String mconfigconsolamode = "";
public static String mconfigfindelinea = "";
public static String mconfigenableeco = "";
public static String mconfigfilesave = "";

private static Preference.OnPreferenceChangeListener
        sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener() {
    @Override
    public boolean onPreferenceChange(Preference preference, Object value) {
        String stringValue = value.toString();

        if (preference instanceof ListPreference) {
            ListPreference listPreference = (ListPreference) preference;
            int index = listPreference.findIndexOfValue( stringValue );
            preference.setSummary(index >= 0 ? listPreference.getEntries()[index] : null );
        }else {
            preference.setSummary( stringValue );
        }
        return true;
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getFragmentManager().beginTransaction().replace(android.R.id.content, new MyPreferenceFragment()).commit();
    setupActionBar();
}


private void setupActionBar() {
    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
         actionBar.setDisplayHomeAsUpEnabled( true );
    }
}

private static void bindPreferenceSummaryToValue(Preference preference) {

    preference.setOnPreferenceChangeListener( sBindPreferenceSummaryToValueListener );
    sBindPreferenceSummaryToValueListener.onPreferenceChange( preference,PreferenceManager
            .getDefaultSharedPreferences( preference.getContext() )
            .getString( preference.getKey(), "" ) );
}

public static class MyPreferenceFragment extends PreferenceFragment {
    @Override
    public void onCreate(final Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.pref_setup_com);

        setHasOptionsMenu( true );

        bindPreferenceSummaryToValue( findPreference( "config_baud_rate" ) );
        bindPreferenceSummaryToValue( findPreference( "config_data_bit" ) );
        bindPreferenceSummaryToValue( findPreference( "config_bit_stop" ) );
        bindPreferenceSummaryToValue( findPreference( "config_parity" ) );
        bindPreferenceSummaryToValue( findPreference( "config_flow_control" ) );
        bindPreferenceSummaryToValue( findPreference( "config_font_size" ) );
        bindPreferenceSummaryToValue( findPreference( "config_consola_mode" ) );
        bindPreferenceSummaryToValue( findPreference( "config_fin_delinea" ) );
        bindPreferenceSummaryToValue( findPreference( "config_filesave" ) );

        ListPreference SPconfigbaudrate2 = (ListPreference) findPreference("config_baud_rate");
        mconfigbaudrate = SPconfigbaudrate2.getValue();

        ListPreference SPconfigdatabit2 = (ListPreference) findPreference("config_data_bit");
        String mconfigdatabit = SPconfigdatabit2.getValue();

        ListPreference SPconfigbitstop2 = (ListPreference) findPreference("config_bit_stop");
        String mconfigbitstop = SPconfigbitstop2.getValue();

        ListPreference SPmconfigparity2 = (ListPreference) findPreference("config_parity");
        String mconfigparity = SPmconfigparity2.getValue();

        ListPreference SPconfigfontsize2 = (ListPreference) findPreference("config_font_size");
        String mconfigfontsize = SPconfigfontsize2.getValue();

        ListPreference SPconfigconsolamode2 = (ListPreference) findPreference("config_consola_mode");
        String mconfigconsolamode = SPconfigconsolamode2.getValue();

        ListPreference SPconfigfindelinea2 = (ListPreference) findPreference("config_fin_delinea");
        String mconfigfindelinea = SPconfigfindelinea2.getValue();

        TwoStatePreference SPconfigenableeco2 = (TwoStatePreference) findPreference("config_enable_eco");
        Boolean mconfigenableecoX = SPconfigenableeco2.isChecked();
        String mconfigenableeco = String.valueOf(mconfigenableecoX);

        ListPreference SPconfigfilesave2 = (ListPreference) findPreference("config_filesave");
        String mconfigfilesave = SPconfigfilesave2.getValue();
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    int id = item.getItemId();
    if (id == android.R.id.home) {
        Intent intent2 = new Intent(this, MainActivity.class);
        intent2.putExtra("mconfigbaudratex",mconfigbaudrate);
        intent2.putExtra("mconfigdatabitx",mconfigdatabit);
        intent2.putExtra("mconfigbitstopx", mconfigbitstop);
        intent2.putExtra("mconfigparityx", mconfigparity);
        intent2.putExtra("mconfigfontsizex", mconfigfontsize);
        intent2.putExtra("mconfigconsolamodex", mconfigconsolamode);
        intent2.putExtra("mconfigfindelineax", mconfigfindelinea);
        intent2.putExtra("mconfigenableecox", mconfigenableeco);
        intent2.putExtra("mconfigfilesavex", mconfigfilesave);

        startActivityForResult(intent2, 0);
    }
    return super.onOptionsItemSelected( item );
   }
 }

Could someone tell me what my error is? The data in listPreference is loaded and displayed correctly, if I replace the other variables except the first one with a text string, they all arrive correctly

In an app I want to send a variable Stringusing it Intentto another activity, from the method onOptionsItemSelected, my problem is that the variable is generated in a method PreferenceFragment, no matter how many declarations I try to make, it always gives me an error, because PreferenceFragmentthe variable mconfigenableecoxis not valid (it is paints red), can someone tell me what my mistake is and how to correct it.

Here is my code:

public class UsbSettingActivity extends AppCompatPreferenceActivity {

public String mconfigenableecox = "";

    .
    .
    public static class MyPreferenceFragment extends PreferenceFragment {
    @Override
    public void onCreate(final Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.pref_setup_com);

        setHasOptionsMenu( true );
    .
    .
        TwoStatePreference SPconfigenableeco2 = (TwoStatePreference) findPreference("config_enable_eco");
        Boolean mconfigenableecoX = SPconfigenableeco2.isChecked();
        String mconfigenableeco = String.valueOf(mconfigenableecoX);
        mconfigenableecox = mconfigenableeco;
   .
   .
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == android.R.id.home) {
        Intent intent = new Intent(this, MainActivity.class);
        intent.putExtra("EcoSet", mconfigenableecox);
        startActivityForResult(intent, 0);
    }
    return super.onOptionsItemSelected( item );
}

I am trying to pass a string variable from one activity to another activity without success, this is my data:

Inside Activity1 I have this String: stringInfoUSB and this intent

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
.
.
final UsbDevice device = driver.getDevice();
final String stringInfoUSB = String.format("Driver: %s  Vendor: %s Product: %s",driver.getClass().getSimpleName(),
                HexDump.toHexString((short) device.getVendorId()),
                HexDump.toHexString((short) device.getProductId()));
.
.
.
@Override
public boolean onNavigationItemSelected(MenuItem item) {

    int id = item.getItemId();

    if (id == R.id.nav_usb) {
        Intent intent = new Intent(this, UsbInfoActivity.class);
        intent.putExtra("infoUSB", stringInfoUSB);
        startActivity(intent);
    }

This is the activity2 that receives the variable:

public class UsbInfoActivity extends AppCompatActivity {
private Button mBotonCancel;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_usb_info );

    Bundle bundle = getIntent().getExtras();                        
    String textoImportado1=bundle.getString("Info_USB");

    mBotonCancel = (Button)findViewById( R.id.bt2_SendButton ) ;

    String bufferTexto2 = textoImportado1;
    TextView mDumpTextView = (TextView)findViewById(R.id.tv2_ReadValues);
    mDumpTextView.setText(bufferTexto2);

    mBotonCancel.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent2 = new Intent(v.getContext(), MainActivity.class);
            startActivityForResult(intent2, 0);
        }
    });

}

I need to send this string to the activity2 called UsbInfoActivity, after selecting an item from a navigation bar, but stringinfoUSB gives me ERROR!, can someone tell me what error?

I need to enter only hexadecimal characters to an editText in Android, but these characters must be entered in pairs, after each pair a space must automatically be inserted and then the next pair and so on, could someone tell me how to do it

To enter the hex characters I am using this code:

 @Override
 public boolean onEditorAction(TextView v, int actionId,
 KeyEvent event) {
 if (actionId == EditorInfo.IME_ACTION_DONE
  || event.getAction() == KeyEvent.ACTION_DOWN
  && event.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
  Log.d("", tv.getText().toString());
  return true;
  }
 return false;
 }
});

and the xml layout is like this:

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<EditText
    android:id="@+id/edittext_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:digits="0123456789ABCDEF"
    android:imeOptions="actionDone"
    android:inputType="textCapCharacters" />

I am making an app and I need the textView to show the at commands that it sent to the outside and also have to show the responses,

to differentiate which is a question and which is an answer, that's why I need to change the color of the text depending on whether it leaves or enters the device, by default the answers are configured in the xml layout to blue, using this code I try to change only the questions in red, but there are errors and I can't get what I need

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_main );

    mDumpTextView = (TextView) findViewById(R.id.tv1_ReadValues);
    mTextoEditor1 = (EditText)findViewById( R.id.et1_WriteValues ) ;
    mTextoEditor2 = (EditText)findViewById( R.id.et2_WriteValues ) ;
    mBotonSend1 = (Button)findViewById( R.id.bt1_SendButton ) ;
    mBotonSend2 = (Button)findViewById( R.id.bt2_SendButton ) ;

    mBotonSend1.setOnClickListener( new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mTextoEditor1.length() != 0x00){

                String bufferTXD1 = mTextoEditor1.getText().toString() + "\r" + "\n";
                mDumpTextView.append(bufferTXD1);
                mTextoEditor1.setText( "" );

            }
        }
    } );

    mBotonSend2.setOnClickListener( new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mTextoEditor2.length() != 0x00){

                String bufferTXD2 = mTextoEditor2.getText().toString() + "\r" + "\n";
                mDumpTextView.append(bufferTXD2);

                nroBuffer = mDumpTextView.length();
                nroChar = bufferTXD2.length();
                starChar = nroBuffer - nroChar;
                nroChar = nroChar - 2;
                endChar = nroBuffer - nroChar;

                SpannableStringBuilder builder = new SpannableStringBuilder();

                SpannableString textColor = new SpannableString(bufferTXD2);
                textColor.setSpan(new ForegroundColorSpan(Color.RED), starChar, endChar, 0);
                builder.append(textColor);


                mTextoEditor2.setText( "" );
            }
        }
    } );

}

}

Could someone tell me how to do it, thanks.

If you want to use a SpannableString, you can do it this way, defining to use the color red ("#FF0000") or blue ("#0000FF") ;

There must be some error, because the input and output text comes out of the color (blue), even I have already changed to color, red, green, yellow... it always comes out blue.