AutoRing Android Service Creation Walkthrough

package droid.ar;

import droid.ar.R;
import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.MenuItem;
import android.view.View.OnCreateContextMenuListener;
import android.widget.TextView;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;
import android.content.Intent;
import android.view.View;

public class AutoRingActivity extends Activity 
	//implement click listeners so we can use this class to process menu & button clicks
	implements MenuItem.OnMenuItemClickListener, View.OnClickListener {

	//class level variables
	AutoRingActivity mMainActivity;
	LinearLayout mMainView;
	Button btnConnectedOption, btnDisconnectedOption, btnStartStop;
	private int mConnectAction = 2; //default is Ring
	private int mDisconnectAction = 1; //default is Vibrate

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		//housekeeping
		setContentView(R.layout.main);
		mMainView = (android.widget.LinearLayout) findViewById(R.id.main_view);
		AutoRingSvc.mMainActivity = this; //so service can update GUI
		mMainActivity = this; //for use in anonymous classes

		//get button objects
		btnConnectedOption = ((Button) findViewById(R.id.btnConnectedOption));
		btnDisconnectedOption = ((Button) findViewById(R.id.btnDisconnectedOption));
		btnStartStop = ((Button) findViewById(R.id.btnStartStop));

		//for Android 1.5 and less, we need to add the click listeners in code
		//after Android 1.5, these can be declared in main.xml (android:onClick="onClick")
		btnConnectedOption.setOnClickListener(this);
		btnDisconnectedOption.setOnClickListener(this);
		btnStartStop.setOnClickListener(this);       

		//get user preferences - use defaults if not set
		mConnectAction = getSharedPreferences("AutoRing", 0).getInt("ConnectAction", mConnectAction);
		mDisconnectAction = getSharedPreferences("AutoRing", 0).getInt("DisconnectAction", mDisconnectAction);

		UpdateSvcStatus(); //update text boxes and buttons
        
		//this is called when we pop up the context menu (openContextMenu)
		mMainView.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {   		 
			@Override
			public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
				//we're using the same context menu for the Connect and Disconnect buttons
				Button btnCaller = (Button)v.getTag(); //we passed the calling button in the view tag
				//set menu heading according to calling button
				menu.setHeaderTitle(btnCaller == btnConnectedOption?"When Connected":"When Disconnected");
				//get action based on calling button and current setting
				int action = (v.getTag() == btnConnectedOption) ? mConnectAction : mDisconnectAction;
				//create the menu items according the mActionList string array
				//set the group id to the calling button id for later reference
				//all the menu items have the same listener
				for (int i=0; i<4; i++) 
					menu.add(btnCaller.getId(),i,0, AutoRingSvc.mActionList[i])
					 .setChecked(action == i) //set checked if this item matches current setting
					 .setOnMenuItemClickListener(mMainActivity); //we implemented OnMenuItemClickListener
				//set the menu items to checkable and exclusive so they appear as radio buttons
				menu.setGroupCheckable(btnCaller.getId(), true, true);
			}
		});
    } //onCreate
    
	//this is called when the user clicks a context menu item
	//this is the implementation of OnMenuItemClickListener
	public boolean onMenuItemClick(MenuItem item) {
		//the calling button instance was passed to the context menu
		//the groupid of the menu item is the calling button id
		//update service static value with new setting
		if (item.getGroupId() == R.id.btnConnectedOption)
			mConnectAction = item.getItemId();
		if (item.getGroupId() == R.id.btnDisconnectedOption)
			mDisconnectAction = item.getItemId();

		//store updated settings, these are read in AutoRingSvc.onCreate()
		getSharedPreferences("AutoRing", 0).edit()
		 .putInt("ConnectAction", mConnectAction)
		 .putInt("DisconnectAction", mDisconnectAction)
		 .commit();

		UpdateSvcStatus();	//update GUI
		return true;
	}
    
	//this is called when the user clicks a button on our GUI
	//OnClickListener implementation
	public void onClick(View view) {
		Button btn = (Button)view;
		if (btn.getId()== R.id.btnStartStop)
		{
			AutoRingSvc.mMainActivity = this; //so service can update GUI
			//store service state, this is read in RebootReceiver class
			//if user started service, we will need to restart on reboot
			getSharedPreferences("AutoRing", 0).edit()
			 .putBoolean("StartOnReboot", !AutoRingSvc.mSvcStarted).commit();
			//create service intent (or connect to running service)
			Intent svc = new Intent(mMainActivity, AutoRingSvc.class);
			if (!AutoRingSvc.mSvcStarted) //if not started
				getApplicationContext().startService(svc); //start service 
			else //already started, so attempt stop
				AutoRingSvc.mSvcStarted = !getApplicationContext().stopService(svc); //returns true if stopped successfully
			UpdateSvcStatus(); //update GUI
		}
		//if user clicked on an option button
		if (btn.getId()== R.id.btnConnectedOption || btn.getId()== R.id.btnDisconnectedOption)
		{
			mMainView.setTag(btn); //pass calling button to context menu so we get button id back
			openContextMenu(mMainView); //start option menu
		}
	}
	
	public void UpdateSvcStatus() {
		//update the GUI text fields with the battery and service status
		((TextView) findViewById(R.id.txtBattStatus)).setText(AutoRingSvc.mBatteryStatus);
		((TextView) findViewById(R.id.txtStatus)).setText("AutoRing is "+(AutoRingSvc.mSvcStarted? "running": "stopped"));
		//set text of Start\Stop button
		btnStartStop.setText((AutoRingSvc.mSvcStarted? "Stop": "Start") + " AutoRing"); 

		//if service is running disable the option buttons, else enable them
		btnConnectedOption.setEnabled(!AutoRingSvc.mSvcStarted);
		btnDisconnectedOption.setEnabled(!AutoRingSvc.mSvcStarted);

		//update option button text with current settings
		btnConnectedOption.setText("When Connected: " + AutoRingSvc.mActionList[mConnectAction]);
		btnDisconnectedOption.setText("When Disconnected: " + AutoRingSvc.mActionList[mDisconnectAction]);
		
		//Must be Android 1.6 or higher to add arrow icon to buttons
		if (Integer.parseInt(android.os.Build.VERSION.SDK) > 3) 
		{
			//add arrow icons to option buttons when enabled
			btnConnectedOption.setCompoundDrawablesWithIntrinsicBounds(0,0, btnConnectedOption.isEnabled()? R.drawable.downarrow: 0, 0);
			btnDisconnectedOption.setCompoundDrawablesWithIntrinsicBounds(0,0, btnDisconnectedOption.isEnabled()? R.drawable.downarrow: 0, 0);
		}
	}

	@Override
	public void onPause() { //app moved to background, no need for updates
		super.onPause();
		AutoRingSvc.mMainActivity = null; //disconnect from service
	}

	@Override
	public void onResume() { //app moved to foreground (also occurs at app startup)
		super.onResume();
		AutoRingSvc.mMainActivity = this; //reconnect to service
		UpdateSvcStatus();	//update GUI
	}
     
	@Override 
	public void onDestroy() {
		super.onDestroy();
		//show message so we know when the GUI app is gone and the service is still running
		Toast.makeText( mMainView.getContext(), " Goodbye GUI ", Toast.LENGTH_SHORT).show();
	}
} //AutoRingActivity