How to change layout size (and other parameters) in code

It is really easy to change layout parameters, but you have to pay attention here: I'm changing LinearLayout, but parent of this layout - RelativeLayout. So I have to set LayoutParams for RelativeLayout otherwise I'll get ClassCastException.

LinearLayout layout = (LinearLayout)findViewById(R.id.activity_layout);
layout.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

Easy way to check if soft keyboard is open

Here's the really easy way to handle very specific 'soft' keyboard events: opening and closing.

final RelativeLayout view = (RelativeLayout)findViewById(R.id.activity_loading);
view.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
        public void onGlobalLayout() {
            if ((view.getRootView().getHeight() - view.getHeight()) >    
                    view.getRootView().getHeight()/3) {
            
  // keyboard is open

            } else {
             
  // keyboard is closed
            
     }
        }
    });

ListView fading edge color

Do you have ListView in your application? I'm sure you do. Have you ever try to change color of fading edge of the list? I think you did. For those of you who still struggling with edge color - I found really elegant way to change color:

<ListView
  ...
  android:cacheColorHint="#00000000"
  ...
/>

I did put transparent white color (#00000000) to achieve nice looking integration of the ListView with the rest of UI elements...

Easy and efficient way to get latest location

If you create an application with the use of location based services than you should be aware how critical the time spent in obtaining the coordinates and save battery life. So, instead of requesting location update every time we need it, lets just check what we already have and choose most accurate result within the acceptable time limit. And only in case we don't get any result we will force location update...

public Location LastBestLocation(int minDistance, long minTime) {  
  Location result = null;
  float bestAccuracy = Float.MAX_VALUE;
  long bestTime = Long.MAX_VALUE;

  Context context = getApplicationContext();
  LocationListener locationListener = locationListener;
  LocationManager locationManager = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
  Criteria criteria = new Criteria();
  criteria.setAccuracy(Criteria.ACCURACY_FINE);
  criteria.setPowerRequirement(Criteria.POWER_LOW);

  List matchingProviders = locationManager.getAllProviders();
  for (String provider: matchingProviders) {
    Location location = locationManager.getLastKnownLocation(provider);   
    if (location != null) {
      float accuracy = location.getAccuracy();
      long time = location.getTime();
      if ((time < minTime && accuracy < bestAccuracy)) {
        result = location;
        bestAccuracy = accuracy;
        bestTime = time;
      } else if (time > minTime && bestAccuracy == Float.MAX_VALUE && time < bestTime){
        result = location;
        bestTime = time;
      }
    } 
  }
  
  // check if result is within limits (time and accuracy)
  if (locationListener != null && (bestTime > minTime || bestAccuracy > minDistance)) { 
    String provider = locationManager.getBestProvider(criteria, true);
    if (provider != null) {

      // if there's no result - request location update
      locationManager.requestLocationUpdates(provider, 0, 0, locationListener, context.getMainLooper());
      
      // if GPS Provider is available than register it for location update, 
      // but only for 30 second (usually it's enough time to get fix with clear sky)
      // remove GPS listener if it takes longer than 30 seconds to get GPS fix
      if (provider.equalsIgnoreCase(LocationManager.GPS_PROVIDER)) {
        Handler handler = new Handler();
        handler.postDelayed(new Runnable(){
          @Override
          public void run() { 
            locationManager.removeUpdates(locationListener);              
          }
        }, 30000L);
      }
    }
  }
  return result;
}


protected LocationListener locationListener = new LocationListener() {
  @Override
  public void onLocationChanged(Location location) {
    locationManager.removeUpdates(locationListener);
  }
  
  @Override public void onProviderDisabled(String provider) {}
  @Override public void onProviderEnabled(String provider) {}
  @Override public void onStatusChanged(String provider, int status, Bundle extras) {}
};

How to check if service is running?

There’re situations where you need to check if service is already running. And it’s pretty easy…

private boolean isServiceRunning() {
  ActivityManager manager = (ActivityManager)getSystemService(ACTIVITY_SERVICE);
  for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
    if (“your.servicename”.equals(service.service.getClassName())) {
      return true;
    }
  }
  return false;
}