What's the best way to check if a String contains a URL in Java/Android?

Best way would be to use regular expression, something like below:

public static final String URL_REGEX = "^((https?|ftp)://|(www|ftp)\\.)?[a-z0-9-]+(\\.[a-z0-9-]+)+([/?].*)?$";

Pattern p = Pattern.compile(URL_REGEX);
Matcher m = p.matcher("example.com");//replace with string to compare
if(m.find()) {
    System.out.println("String contains URL");
}

This is simply done with a try catch around the constructor (this is necessary either way).

String inputUrl = getInput();
if (!inputUrl.contains("http://"))
    inputUrl = "http://" + inputUrl;

URL url;
try {
    url = new URL(inputUrl);
} catch (MalformedURLException e) {
    Log.v("myApp", "bad url entered");
}
if (url == null)
    userEnteredBadUrl();
else
    continue();

After looking around I tried to improve Zaid's answer by removing the try-catch block. Also, this solution recognizes more patterns as it uses a regex.

So, firstly get this pattern:

// Pattern for recognizing a URL, based off RFC 3986
private static final Pattern urlPattern = Pattern.compile(
    "(?:^|[\\W])((ht|f)tp(s?):\\/\\/|www\\.)"
            + "(([\\w\\-]+\\.){1,}?([\\w\\-.~]+\\/?)*"
            + "[\\p{Alnum}.,%_=?&#\\-+()\\[\\]\\*$~@!:/{};']*)",
    Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);

Then, use this method (supposing str is your string):

    // separate input by spaces ( URLs don't have spaces )
    String [] parts = str.split("\\s+");

    // get every part
    for( String item : parts ) {
        if(urlPattern.matcher(item).matches()) { 
            //it's a good url
            System.out.print("<a href=\"" + item + "\">"+ item + "</a> " );                
        } else {
           // it isn't a url
            System.out.print(item + " ");    
        }
    }