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Performance at working with strings android

Could somebody tell me what is better in terms of performance?
Is it better to save 2 strings at string.xml, like 'abc' and 'abc:'
Or should I save only the first one and concatenate ':' when needed at Java coding ???

Very difficult to answer depending on what your strings will represent and what you need to append. Localization is also an issue, for example...
Dog // English
Chien // French
Hund // German
Using string resources allows you to create different resource files depending on the locale of the device and Android will automatically use the right localized string resource file. If all you need to do is append a single character such as : then you'll double every string for every language.
If you choose to only save the basic strings and append the character using code, then the code will be universal and you'll simply need to append the character to whatever localized word - potentially a lot more efficient.

Both from storage perspective and performance you should save only "abc";
getting extra data from disk takes far longer as some quick in-memory actions.
storing the same data twice is bad practice in general

If you have to concatenate multiple strings you should use StringBuilder - http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/StringBuilder.html
It's much faster then using '+' or '.concat()'

how to add smilies/emotions in my edittext for a notes app in android?

can any one know about how to add/insert emotions/smiles to text(which ever i typed in my edit text for my notes). i have little confusion about if i want to add these smiles of type .png in to edit text type of string, is it possible? and also i have to save these input into sqlite database. normally i know to store string data taken from edit text.
but along with that text i want to also add smiles symbols where ever my cursor placed and to be store in sqlite data base. and get it back to read.
so guys any ideas, most welcome!

Try to use java (i.e. android) spannable method to implement smiley (i.e.) images for that. You will surely get it, search in google for "how to add images/smiley with java spannable method in android?" you will get good idea.

Reading your question the first thing I can think of is Mapping each image to a sequence of letters, for example :) is smiley.png etc. Now your database also has these smaller representation However while reading from the database you can convert those special character sequences to appropriate image.
For simplicity in seraching those Strings You can wrap them in some less used characters i.e. [ or { or <.

extracting strings from KML file

I am extracting strings from KML file, if the string contains special character like !, #, #, ', " etc. its using codes like '
I am not able to extract entire string if it is like above, by calling getNodeValue(). It is terminating the string at special character.
<name>Continue onto Royal's Market</name>
If i extract the string i am getting only ""Continue onto Royal". I want entire string as
Continue onto Royal's Market.
How to achieve this ?? If anybody familiar with this please reply to this one.
Thanks

Your problem has nothing to do with KML but is general for XML parsning:
Don't use getNodeValue(), as there is no guarantee in DOM that text isn't actually split over several nodes.
Try using getTextContent() instead.
You might also have to replace entities, as in: node.getTextContent().replaceAll("'","'");
In general I wouldnt use DOM at all for extracting data.
I'd use the XmlPullParser as its simpler to work with - and parses faster.

Show a bulleted list from Strings.xml file in android

I have a problem that I want to show a bulleted list contents which is resided in strings.xml file as an array elements. Then the problem is that how to convert the array elements in Html List format? Can any one suggest any solution regarding the same.
Thanks in advance

I just put the symbol directly into the strings.xml without any codes or anything:
<string name="msg_sms_no_note">• Notes and attachments will not be sent.</string>

There's a problem with the approach suggested by some of the answers in this thread of prepending the bullet unicode character (i.e. \u2022) to each of the Strings in the String array: You don't get proper indentation when one or more Strings in the String array span multiple lines. What you get is formatting as follows:
In order to get proper indentation, you're better using BulletSpan. In doing so, you'll get formatting as follows:
To use BulletSpan, you need to create a SpannableStringBuilder instance and append each String in your String array to this SpannableStringBuilder instance. As you append each String, call the setSpan(what:start:end:flags:) method on the SpannableStringBuilder instance passing in a BulletSpan instance for the what parameter. You can find an example of this in the appendBulletSpan(...) Kotlin extension function located here.

I think, the most elegant way of doing this is to load a WebView and put your string in it. this way, you use the common ul/li convention and you can style it at your leisure with CSS.

Use the unicode escape sequence "\u2022" in strings.xml
like so:
<string name="menu_new_trip_desc">View them in: \n\u2022 Table

Keep Strings into .txt file or put them into a Database?

Hey, I have a lot of Strings that I use into my app, the .txt file that I use has ~14000 lines.. and each 3-10 lines are divided into sections like <String="Chapter I"> ... </String> ..
Speaking of performance/speed, should I put the sections into a Database, Or read line by line through the .txt file and check if the section number is the current one? Will this affect speed/performance?
I could also divide each ~2000 lines into a different .txt file so there would be less lines to go through. Is this a bad way of storing data? Thanks

I think sqlite would do the trick. It will probably be way faster than parsing a text file, plus you wont have to maintain the headache of your own ad hoc text database, or build a parser in the first place. Basically, use it, its way easier.

The standard way to deal with Strings in Android is to put them into res/values/strings.xml (I'm pretty sure you can have multiple String files in that directory if you like). If you are developing in Eclipse it will automatically populate the R class (the resource class) with constants that you can use to reference these Strings in your code:
R.string.mystring
Or in XML layouts:
#string/mystring
Or if you're doing something more custom you can use:
String string = getString(R.string.hello);
I would definitely choose this over a .txt file. It's much easier. All the work is done for you! Have a read of this Android article about it.

This is what a database is for. Use it.