I'm trying to develop an app to scan for a BLE device. However, it only scans one time. I tried to use a while loop to loop it but it hangs there. The scanning part is at the proceed function:

Question

package com.example.user.myfriend;

import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothManager; import android.content.Context; import android.content.Intent; import android.graphics.Color; import android.os.Handler; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.widget.RelativeLayout; import android.widget.TextView; import android.widget.Toast;

import org.w3c.dom.Text;

public class MainActivity extends ActionBarActivity { BluetoothAdapter mBluetoothAdapter;

@Override protected void onCreate(Bundle savedInstanceState) {

BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
hello();

}

public void hello() {

if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
    Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

    startActivityForResult(enableBluetooth, 1);


}
proceed();

}

@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == 1) {
    if (resultCode == RESULT_OK) {
        proceed();


    }

}
super.onActivityResult(requestCode, resultCode, data);

}

private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

public void onLeScan(final BluetoothDevice device, final int rssi, final byte[] scanRecord) {

    int startByte = 2;
    boolean patternFound = false;
    while (startByte <= 5) {

        if (((int) scanRecord[startByte + 2] & 0xff) == 0x02 && //Identifies an iBeacon
                ((int) scanRecord[startByte + 3] & 0xff) == 0x15) { //Identifies correct data length
            patternFound = true;
            break;
        }
        startByte++;
    }

    if (patternFound) {

        //Convert to hex String
        byte[] uuidBytes = new byte[16];
        System.arraycopy(scanRecord, startByte + 4, uuidBytes, 0, 16);
        String hexString = bytesToHex(uuidBytes);

        //Here is your UUID
        String uuid = hexString.substring(0, 8) + "-" +
                hexString.substring(8, 12) + "-" +
                hexString.substring(12, 16) + "-" +
                hexString.substring(16, 20) + "-" +
                hexString.substring(20, 32);

        //Here is your Major value
        int major = (scanRecord[startByte + 20] & 0xff) * 0x100 + (scanRecord[startByte + 21] & 0xff);

        //Here is your Minor value
        int minor = (scanRecord[startByte + 22] & 0xff) * 0x100 + (scanRecord[startByte + 23] & 0xff);

        if (major == 1) {
            RelativeLayout hai = (RelativeLayout) findViewById(R.id.hai);
            hai.setBackgroundColor(Color.YELLOW);

        }
        if (major == 2) {
            RelativeLayout hai = (RelativeLayout) findViewById(R.id.hai);
            hai.setBackgroundColor(Color.RED);

        }


    }


}

};

private static String bytesToHex(byte[] bytes) { final char[] hexArray = "0123456789ABCDEF".toCharArray(); char[] hexChars = new char[bytes.length * 2]; for (int j = 0; j < bytes.length; j++) { int v = bytes[j] & 0xFF; hexChars[j * 2] = hexArray[v >>> 4]; hexChars[j * 2 + 1] = hexArray[v & 0x0F]; } return new String(hexChars); }

public void proceed() { boolean scanning = true;

mBluetoothAdapter.startLeScan(mLeScanCallback);


Handler handler = new Handler();
handler.postDelayed(new Runnable() {
    //  @Override
    public void run() {
        mBluetoothAdapter.stopLeScan(mLeScanCallback);


    }
}, 50000000);

}