Monitoring battery use

1. Monitoring battery use

2. New app, BatteryMonitor • Add permission: BATTERY_STATS • The battery is monitored by receiving broadcasts of battery state information • Register to receive broadcasts • In onCreate add • IntentFilterbatteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED); • registerReceiver(batteryLevelReceiver, batteryLevelFilter); • Add broadcast receiver as activity member variable. • BroadcastReceiverbatteryLevelReceiver = new BroadcastReceiver() { • public void onReceive(Context context, Intent intent) { • context.unregisterReceiver(this); • intrawlevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1); • int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1); • int level = -1; • if (rawlevel >= 0 && scale > 0) { • level = (rawlevel * 100) / scale; • } • Log.e("DEBUG","Battery Level Remaining: " + level + "%"); • } • }; • run

3. Show more battery things • Add member variable • TextViewtextView; • String batteryStr = new String(); • Add TextView to layout • Set Misc.LayoutHeight = fill_parent • Set Misc.LayoutWidth = fill_parent • In onCreate, add • textView = (TextView)findViewById(R.id.TextView01); • textView.setMovementMethod(new ScrollingMovementMethod()); • In batteryLevelReceiver.onReceive, add to beginning • batteryStr += "------------------------------------------------\n"; • Calendar calendar = new GregorianCalendar(); • batteryStr += "time: "+calendar.get(Calendar.HOUR)+":"+calendar.get(Calendar.MINUTE)+":"+calendar.get(Calendar.SECOND)+"\n"; • Change Log.e("DEBUG","Battery Level Remaining: " + level + "%");, to • batteryStr += "Battery Level Remaining: " + level + "%\n"; • At the end ofbatteryLevelReceiver.onReceive, add • textView.setText(batteryStr); • Run • Plug and unplug until textview is full and check that view is scrollable

4. Battery plugged state • In batteryLevelReceiver.onReciever, before textView.setText…, add • int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1); • switch (plugged) { • case 0: • batteryStr += "unplugged\n"; • break; • case BatteryManager.BATTERY_PLUGGED_AC: • batteryStr += "Plugged into AC\n"; • break; • case BatteryManager.BATTERY_PLUGGED_USB: • batteryStr += "Plugged into USB\n"; • break; • default: batteryStr += "unknown plugged state\n"; • }

5. Battery status • int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1); • switch (status) { • case BatteryManager.BATTERY_STATUS_CHARGING: • batteryStr += "battery is charging\n"; • break; • case BatteryManager.BATTERY_STATUS_DISCHARGING: • batteryStr += "battery is discharging\n"; • break; • case BatteryManager.BATTERY_STATUS_FULL: • batteryStr += "battery is full\n"; • break; • case BatteryManager.BATTERY_STATUS_NOT_CHARGING: • batteryStr += "battery is not charging\n"; • break; • case BatteryManager.BATTERY_STATUS_UNKNOWN : • batteryStr += "battery status is unknown\n"; • break; • default: • batteryStr += "battery status should not happen\n"; • break; • }

6. Battery type, temperature, voltage, • String tech = intent.getStringExtra(BatteryManager.EXTRA_TECHNOLOGY); • batteryStr += "technology: " + tech +"\n"; • int temp = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE, -1); • batteryStr += "temp: " + temp+"\n"; • int voltage = intent.getIntExtra(BatteryManager.EXTRA_VOLTAGE, -1); • batteryStr += "voltage: " + voltage+"\n";

7. Battery health • int health = intent.getIntExtra(BatteryManager.EXTRA_HEALTH,-1); • switch (health) { • /*case BatteryManager.BATTERY_HEALTH_COLD: • batteryStr += "health = cold\n"; • break; //in documentation, but not supported • */ • case BatteryManager.BATTERY_HEALTH_DEAD: • batteryStr += "health = dead\n"; • break; • case BatteryManager.BATTERY_HEALTH_GOOD: • batteryStr += "health = good\n"; • break; • case BatteryManager.BATTERY_HEALTH_OVERHEAT: • batteryStr += "health = overheat\n"; • break; • case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE: • batteryStr += "health = over voltage\n"; • break; • case BatteryManager.BATTERY_HEALTH_UNKNOWN: • batteryStr += "health = unknown\n"; • break; • case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE: • batteryStr += "health = unspecified failure\n"; • break; • default: • batteryStr += "health state: should not happen\n"; • break; • }

8. More fun with battery level • Let’s estimate battery charge/discharge rate • Add member variables • long lastTime = 0; • double lastLevel; • After level is computed, add • double rate = 0; • double terminationTime=0; • if (lastTime!=0) { • rate = (level - lastLevel)/(calendar.getTimeInMillis()-lastTime)*1000.0; • if (rate>0) { • terminationTime = (100-level)/rate/3600; • batteryStr += "charged in "+terminationTime+" hours\n"; • } • if (rate<0) { • terminationTime = -level/rate/3600; • batteryStr += "discharged in "+terminationTime+" hours\n"; • } • } • lastTime = calendar.getTimeInMillis(); • lastLevel = level;

9. Battery Monitor Service • Make new class • BatteryMonitorService • Derived from android.app.Service • To manifest, add service, i.e, • In Application tab • Application nodes, add • Select radio button “Create a new element at the top level, in application” • Select “service” • Select ok • With the new service highlighted, • In name (on the right), add • BatteryMonitorService • Or, select “browse” and (wait) and select BatteryMonitorService

10. In BatteryMonitorService • @Override • public void onCreate() { • super.onCreate(); • Log.d("BatteryMonitorService","Created"); • IntentFilterbatteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED); • registerReceiver(batteryLevelReceiver, batteryLevelFilter); • } • private final Binder binder = new LocalBinder(); • public class LocalBinder extends Binder { • BatteryMonitorServicegetService() { • Log.d("BatteryMonitorService","localbinder"); • return BatteryMonitorService.this; • } • } • Change onBind, to • @Override • public IBinderonBind(Intent intent) { • // TODO Auto-generated method stub • return binder; • } • @Override • public void onDestroy() { • super.onDestroy(); • Log.d("BatteryMonitorService","Destroyed"); • unregisterReceiver(batteryLevelReceiver); • }

11. In BatteryMonitorService • Move broadcast receiver from activity to service • Move member variables • String batteryStr = new String(); • long lastTime = 0; • double lastLevel; • BroadcastReceiverbatteryLevelReceiver = new BroadcastReceiver() { • public void onReceive(Context context, Intent intent) { • ……

12. In BatteryMonitor • Start service. In OnCreate, add • startService(new Intent(this, BatteryMonitorService.class)); • bindService(new Intent(this, BatteryMonitorService.class), connectionToMyService, BIND_AUTO_CREATE); • Add member variable • boolean started = false; • After onCreate, add • private BatteryMonitorService batteryMonitorService = null; • private ServiceConnection connectionToMyService = new ServiceConnection() { • @Override • public void onServiceConnected(ComponentName className, IBinder rawBinder) { • batteryMonitorService = ((BatteryMonitorService.LocalBinder)rawBinder).getService(); • started = true; • } • @Override • public void onServiceDisconnected(ComponentName name) { • batteryMonitorService = null; • started = false; • } • };

13. In BatteryMonitor • We need to get the batteryStr from the service and post it on the textview. • We can use a intent to send the message to get the string • IntentFilter intentFilter = new IntentFilter(); • intentFilter.addAction("edu.udel.eleg454.NewBatteryMonitorStringIsReady"); • registerReceiver(new BroadcastReceiver() { • public void onReceive(Context context, Intent intent) { • Log.d("DEBUG","Received intent "+intent); • textView.setText(batteryMonitorService.batteryStr); • } • },intentFilter); • Let’s get the string when the UI becomes active after being out of focus • @Override • public void onResume() { • super.onResume(); • if (started) { • textView.setText(batteryMonitorService.batteryStr); • } • } • // note: batteryMonitorService is only valid after the connection with the service has been established. See connectionToMyService

14. In BatteryMonitorService • At the end of BroadcastReceiverbatteryLevelReceiver = new BroadcastReceiver() { …. • Remove • textView.setText(batteryStr); • Add • Intent broadcastIntent = new Intent(); • broadcastIntent.setAction("edu.udel.eleg454.NewBatteryMonitorStringIsReady"); • sendBroadcast(broadcastIntent); • Run and play with gps on, wifi, etc. and see impact on battery usage