Android Question Thread stop

[stari]

How can i stop the thread once it starts ?
Code:

#Region  Project Attributes
    #ApplicationLabel: StariSound_thr
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: unspecified
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim nativeMe As JavaObject
    Dim thread1 As Thread
    Dim Lock1 As Lock
 
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.

    Private EditText1 As EditText
    Private EditText2 As EditText
    Private Button1 As Button
    Private Button2 As Button
End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    Activity.LoadLayout("main")

    If FirstTime Then
        thread1.Initialise ("Thread1")
    End If 
    nativeMe.InitializeContext

End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub Thread1_Ended(fail As Boolean, err As String) 'An error or Exception has occurred in the Thread

Log("Thread1 ended")

End Sub

Sub thread_Sub1
    Dim freq As Double       'frequency to play
    Dim dur As Double        'play for 5 seconds
    freq = EditText1.Text
    dur = EditText2.text
    nativeMe.RunMethod("playTone",Array(freq,dur))  'start the java code - it will run in the new thread and not in the main thread
End Sub

Sub Button1_Click
    Log("Button1_Click")
    Dim args(0) As Object
    Lock1.Initialize(True)
    thread1.Name = "B4A Thread 1"
    thread1.Start(Null, "Thread_Sub1", args)           'start a new thread to run the java code in
End Sub

Sub Button2_Click
    'Stop pulses ??? How ???
    Log("Reacting to button 2 while java code thread is running") 
End Sub


#If Java

import android.media.AudioTrack;     //you need to add this as it is not part of the code posted on Stackoverflow - compiler will complain if it can't find a reference to AudioTrack so search for the correct way to import it on the web
import android.media.AudioFormat;    //you need to add this as it is not part of the code posted on Stackoverflow - see comment above
import android.media.AudioManager;   //you need to add this as it is not part of the code posted on Stackoverflow - see comment above


public void playTone(double freqOfTone, double duration) {
//double duration = 1000;                // seconds
//   double freqOfTone = 1000;           // hz
    int sampleRate = 8000;              // a number

    double dnumSamples = duration * sampleRate;
    dnumSamples = Math.ceil(dnumSamples);
    int numSamples = (int) dnumSamples;
    double sample[] = new double[numSamples];
    byte generatedSnd[] = new byte[2 * numSamples];
 
    AudioTrack audioTrack = null;                                   // Get audio track
 
    if (freqOfTone == 0) {
        //audioTrack.release(); 
        audioTrack = null;
        return;
    }
 

    for (int i = 0; i < numSamples; ++i) {      // Fill the sample array
        sample[i] = Math.sin(freqOfTone * 2 * Math.PI * i / (sampleRate));
    }

    // convert to 16 bit pcm sound array
    // assumes the sample buffer is normalized.
    // convert to 16 bit pcm sound array
    // assumes the sample buffer is normalised.
    int idx = 0;
    int i = 0 ;

    int ramp = numSamples / 20 ;                                    // Amplitude ramp as a percent of sample count


    for (i = 0; i< ramp; ++i) {                                     // Ramp amplitude up (to avoid clicks)
        double dVal = sample[i];
                                                                    // Ramp up to maximum
        final short val = (short) ((dVal * 32767 * i/ramp));
                                                                    // in 16 bit wav PCM, first byte is the low order byte
        generatedSnd[idx++] = (byte) (val & 0x00ff);
        generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
    }


    for (i = i; i< numSamples - ramp; ++i) {                        // Max amplitude for most of the samples
        double dVal = sample[i];
                                                                    // scale to maximum amplitude
        final short val = (short) ((dVal * 32767));
                                                                    // in 16 bit wav PCM, first byte is the low order byte
        generatedSnd[idx++] = (byte) (val & 0x00ff);
        generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
    }

    for (i = i; i< numSamples; ++i) {                               // Ramp amplitude down
        double dVal = sample[i];
                                                                    // Ramp down to zero
        final short val = (short) ((dVal * 32767 * (numSamples-i)/ramp ));
                                                                    // in 16 bit wav PCM, first byte is the low order byte
        generatedSnd[idx++] = (byte) (val & 0x00ff);
        generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);
    }

 
    try {
        int bufferSize = AudioTrack.getMinBufferSize(sampleRate, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
        audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                sampleRate, AudioFormat.CHANNEL_OUT_MONO,
                AudioFormat.ENCODING_PCM_16BIT, bufferSize,
                AudioTrack.MODE_STREAM);
        audioTrack.play();                                          // Play the track
        audioTrack.write(generatedSnd, 0, generatedSnd.length);     // Load the track
    }
    catch (Exception e){
    }
 
 
    if (audioTrack != null) audioTrack.release();           // Track play done. Release track.
}



#End If