Monitoring battery use
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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
– IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
– registerReceiver(batteryLevelReceiver, batteryLevelFilter);
Add broadcast receiver as activity member variable.
– BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
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public void onReceive(Context context, Intent intent) {
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context.unregisterReceiver(this);
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int rawlevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
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int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
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int level = -1;
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if (rawlevel >= 0 && scale > 0) {
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level = (rawlevel * 100) / scale;
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}
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Log.e("DEBUG","Battery Level Remaining: " + level + "%");
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}
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};
• run
Show more battery things
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Add member variable
– TextView textView;
– 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());
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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";
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Change Log.e("DEBUG","Battery Level Remaining: " + level + "%");, to
– batteryStr += "Battery Level Remaining: " + level + "%\n";
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At the end of batteryLevelReceiver.onReceive, add
– textView.setText(batteryStr);
• Run
– Plug and unplug until textview is full and check that view is scrollable
Battery plugged state
• In batteryLevelReceiver.onReciever, before textView.setText…, add
– int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
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switch (plugged) {
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case 0:
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batteryStr += "unplugged\n";
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break;
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case BatteryManager.BATTERY_PLUGGED_AC:
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batteryStr += "Plugged into AC\n";
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break;
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case BatteryManager.BATTERY_PLUGGED_USB:
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batteryStr += "Plugged into USB\n";
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break;
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default: batteryStr += "unknown plugged state\n";
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}
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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;
}
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";
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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;
}
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;
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
In BatteryMonitorService
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@Override
public void onCreate() {
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super.onCreate();
Log.d("BatteryMonitorService","Created");
IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
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}
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private final Binder binder = new LocalBinder();
public class LocalBinder extends Binder {
registerReceiver(batteryLevelReceiver, batteryLevelFilter);
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BatteryMonitorService getService() {
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Log.d("BatteryMonitorService","localbinder");
return BatteryMonitorService.this;
}
}
Change onBind, to
@Override
public IBinder onBind(Intent intent) {
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// TODO Auto-generated method stub
return binder;
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}
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@Override
public void onDestroy() {
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}
super.onDestroy();
Log.d("BatteryMonitorService","Destroyed");
unregisterReceiver(batteryLevelReceiver);
In BatteryMonitorService
• Move broadcast receiver from activity to service
• Move member variables
– String batteryStr = new String();
– long lastTime = 0;
– double lastLevel;
• BroadcastReceiver batteryLevelReceiver = new
BroadcastReceiver() {
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public void onReceive(Context context, Intent intent) {
• ……
In BatteryMonitor
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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;
• }
– };
In BatteryMonitor
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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);
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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
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In BatteryMonitorService
• At the end of BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
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– 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