HW1.java

package com.example.mitflashlight;///this should be your package file name!

import android.graphics.Color;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {
	
	//***Define your Instance Variables***
	//I've left mine here but feel free to do it your own way
	
	private boolean isLightOn = false;
	private Camera camera;
	private Button button;
	private View v;
	
	

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
	   /* Retrieve the layout elements (buttonFlashlight and backgroundView) and cast them
		*  into objects we can use here. 
		*/
		
		button = (Button) findViewById(R.id.buttonFlashlight);
		v = //INSERT CODE the same as above but for backgroundView and cast it into a View object v! (one line)

		
		/*
		 * Retrieve the application's context (basically the state in which it's in) and ask it for
		 * its PackageManager. This PackageManager will then allow us to figure out if the 
		 * phone has a Camera. You will want to use the hasSystemFeature method of the PackageManager class
		 * (google it) in an if-statement as I've setup for you below
		 */
		
		Context context = this;		
		PackageManager pm = context.getPackageManager();
	
		//if(INSERT CODE to check if device has camera){ 
			Log.e("err", "Your device has no camera!");//this prints a message in the LogCat when we run our app!
			return;//we escape out of here since there's no camera
		//}
		
		
		
		//start the camera
		camera = Camera.open();
		final Parameters p = camera.getParameters();
		 
		
		///set the clicklistener on our button
		button.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {

				if (isLightOn) {
					
					
					/*
					 * INSERT CODE here that does the following:
					 * 1. Prints to the LogCat the state you are about to change the light to ("Flashlight is on/off!")
					 * 2. Turns on or off the flash (google "setFlashMode" on Parameters of the camera ('p')
					 * 3. Starts or stops the preview (required for camera access) [e.g. camera.stopPreview(); is run when you want to switch it off]
					 * 4. Changes the background color of our backgroundView (which we'ved named 'v' above)
					 * 5. Adjusts the boolean value accordingly (so we can toggle it again next time)
					 */



				} else {

					/*
					 * INSERT CODE here that does the following:
					 * 1. Prints to the LogCat the state you are about to change the light to ("Flashlight is on/off!")
					 * 2. Turns on or off the flash (google "setFlashMode" on Parameters of the camera ('p')
					 * 3. Starts or stops the preview (required for camera access) [e.g. camera.stopPreview(); is run when you want to switch it off]
					 * 4. Changes the background color of our backgroundView to Color.WHITE when the light is on and Color.BLACK when the light is off (which we'ved named 'v' above)
					 * 5. Adjusts the boolean value accordingly (so we can toggle it again next time)
					 */


				}

			}
		});
		
		
	}
	
	@Override
	protected void onStop() {
		super.onStop();
		
		/*
		 * Here we handle the case when the app is Stopped (via exit or by the OS)
		 * [no need for code here, just understand why we've put this here in the onStop Method of the application lifecycle]
		 */
		if (camera != null) {
			camera.release();
		}
	}

}