Why equals might not return true

Question

I have this string: "no_questions_by_user" in a variable named result.

than I do this check:

if ( result != null && result.equals( "no_user_id" ) )
{
        Log.d( "Post execute: " , "NOOOT  OKKKK - no user id" );    
}
else
if ( result != null && result.equals( "database_error" ) )
{
        Log.d( "Post execute: " , "NOOOT  OKKKK - database error" );    
}
else
if ( result != null && result.equals( "no_questions_by_user" ) )
{           
        Log.d( "Post execute: " , "NOOOT  OKKKK - no questions by user so far" );   
}
else
{
  Log.d( "MyQuestionsActivity" , "In JSON parsing area.." );                
}

and it always goes to the last else. But in my understanding it should really go to the block which checks result.equals( "no_questions_by_user" )

any idea why that block does not get executed?

Thanks!!

Answer 1

The code looks good. Your variable result must have another value.

My guess is that there are some whitespaces at the end or beginning of your result string.

Answer 2

Personally, I think this code is a hot mess.

I'd write one method that took in a result and looked up a message in a Map. All those if tests are making my eyes bleed:

private static final Map<String, String> LOG_MESSAGE_MAP;

static {
    LOG_MESSAGE_MAP = new HashMap<String, String>();
    // put all your result, message pairs in here
}

public void logResultDependentMessage(String result) {
    log.debug(LOG_MESSAGE_MAP.get(result));
}

Now adding new result, message pairs just means inserting into the map. If you're using something like Spring you can do it in configuration and not touch the code.

Answer 3

尝试：

result.trim().equals( "no_questions_by_user" )

Answer 4

Did you see "no_questions_by_user" in a debbugger ?

You can try to trim it before the test, as spaces are hard to detect in debuggers.

Answer 5

Make sure there are no white spaces in the value of the "result" variable. Before entering the if statements, you can do a print line like this one.

System.out.println("The Value of result variable is=\"" + result + "\"");

You might as well do this

if ( result != null && result.trim().equals( "no_questions_by_user" ) )
{           
        Log.d( "Post execute: " , "NOOOT  OKKKK - no questions by user so far" );   
}

Answer 6

我建议您使用一些静态变量来存储您的字符串，从而避免键入错误。