android flash turn on/off using button while camera is running

I saw that there are many questions liek this but I didn't find any way. In my app I have my own Camera with some options , and also have button named btnFlash for turning on/off camera's flash light while camera is running. I tried many ways, but nothing worked as on Samsung tab and HTC. here is one of them

ImageButton btnFlash = (ImageButton) findViewById(R.id.btn_flash);
        btnFlash.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {

                Context context = getApplicationContext();
                if( context .getPackageManager().hasSystemFeature(getPackageManager().FEATURE_CAMERA_FLASH)) {
                    Parameters params = mCamera.getParameters();
                    if(isFlashOn) {
                        params.setFlashMode(Parameters.FLASH_MODE_OFF);
                        mCamera.setParameters(params);
                        isFlashOn = false;
                    } else {
                        params.setFlashMode(Parameters.FLASH_MODE_ON);
                        mCamera.setParameters(params);
                        isFlashOn = true;
                    }
                }
            }
        });

1. Can anyone suggest some good tutorial or some code?
2. Can same code work on e.g. HTC but not work on samsung? I mean can I wrote some code for any type of android device?

Thanks in advance..

Go through this link. This helps me to achieve flash functionality in almost all devices.

Import this SVN project.

http://code.google.com/p/torch/source/checkout