ANDROID: If...Else as Switch on String

Question

I'm writing an Android app for work that shows the status of our phone lines, but thats neither here nor there.

I make a call to one of our servers and get returned JSON text of the status. I then parse this putting each line into a SortedMap (TreeMap) with the Key being the name of the line and my own class as the value (which holds status and other details).

This all works fine.

When the app runs it should then show each line and the info I have retrieved, but nothing gets updated.

The JSON is returned and added to the Map correctly.

This is a snapshot of the code that isn't working. I simply iterate through the map and depending on the value of key update the relevant TextView. The problem I am having is that when it gets to the IF statement that matches it never runs that code. It skips it as if values don't match.

I can't see any errors. Is this the only way to do this as I know you can't use Switch..Case etc?

Can anyone see my error? I've been coding on Android for 1 week now so its probably a newbie error!!

Thanks Neil

Iterator iterator = mapLines.entrySet().iterator();

while(iterator.hasNext())
{
// key=value separator this by Map.Entry to get key and value
Map.Entry<String, Status> mapEntry = (Map.Entry<String, Status>)iterator.next();

// getKey is used to get key of Map
String key = (String)mapEntry.getKey();

// getValue is used to get value of key in Map
Status value = (Status)mapEntry.getValue();

if(key == "Ski")
{
    TextView tvStatus = (TextView)findViewById(R.id.SkiStatus);

    tvStatus.setText(value.Status);
}
else if(key == "Cruise")
{
    TextView tvStatus = (TextView)findViewById(R.id.CruiseStatus);

    tvStatus.setText(value.Status);
}
else if(key == "Villas")
{
    TextView tvStatus = (TextView)findViewById(R.id.VillasStatus);

    tvStatus.setText(value.Status);
}
}

Answer 1

You must use equals() to compare String objects in Java. Otherwise you just compare if the two objects are the same instance of the String class and don't compare their actual content:

if (key.equals("Ski")) {
  ...
}

Or, to avoid a NullPointerException if key might be null:

if ("Ski".equals(key)) {
  ...
}

Answer 2

checking key with the string literal "Ski", you can use like below . This will prevent nullpointer exception.

if ("Ski".equals(key)) 
{ 
  ... 
} 

Answer 3

I prefer to use maps in this case because they eliminate the need for duplicated code and long if else constructs. I don't know where in your code this snippet occurs so this may not apply in your case but just to mention it.

Use a Map to get the correct resource for your String and set the status.

The code would look something like this:

First initialize the map:

Map<String, Integer> textViews = new HashMap<String, Integer>();
textViews.put("Ski", R.id.Ski);
textViews.put("Cruise", R.id.Cruise);
textViews.put("Villas", R.id.Villas);

Then retrieve the correct id and set the text:

((TextView) findViewById(textViews.get(key))).setText(status);

This will reduce the big if else construct a lot and adding a textview will be as easy as changing the map.