Plain and, hopefully simply...
-What I would like to do is make a list of strings.
-I would like to add to this list while in the application.
-Finally, I want to get each String from this list.
This must be saved somehow so that when you close it and open it back up, the list will save...
How should I get around to this? SharedPreferences? An SQL Database? What should I use to accomplish this?
I vote SharedPreferences since it will be faster and will persist throughout the life span of the application.
If you need to have the saved data made available during the next time the app is run, you will most likely want to use a DB
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I want to create a javafx project, but does it need Database?
when I create this program save these name when I input this name and other. I mean save the result in the program and show me when I run it, I don’t need to be store for along time .just for that time when I will run it?
Short answer is no, JavaFX can run without database and you don't need to use it.
If you need to sava data that only while program is running but don't need to save it for next use of program then you can simply use some Collection or custom data structure to hold what you need in runtime, but bare in mind that this means that all data will reset once you quit program.
If you need to save data even when program shuts down then you will need to use some kind of database, if you want to save a small amount of data then you can use json, xml or even raw txt files, for more data you should take look at some SQL/NoSQL database.
I'm starting to work on a new Java desktop app that should help me and my colleagues learn vocabulary. It will contain around 700 words, some texts (that point to the words contained in them) and maybe some images (not sure about that part yet). The data will never change and I want the program to be able to run offline.
The question is: Should I use database, text file or serialize the data into file? Or perhaps if there is any other option I don't know about? If you could explain your choice in detail I would be glad.
If the data never changes and is only 700 words it would probably be easiest to use a file.
If your data was a bit more complex and had many fields and was being constantly updated, a database would be more preferable but a csv file could still be used.
Since you want to access this data offline and data never changes, I think the best option would be to just use text file, which will be more efficient in terms of access and speed.
Keep all the data in memory as Serializable Java objects, and store them serialized when your application is not running. Evaluate airomem - really nice solution that would perfectly work for you.
I display dates to the user in a layout that are let's say are textual.
When the user presses a button I want to get the information in those fields that represent these "dates" but if I get the text in them is not of value to me.
I would need to store somewhere the original dates that created these "textual" elements and fetch them from there.
Is there a specific construct in android that one can use as a stash area or should I just use a static class with variable to hold them?
In your case, you should use SharedPreferences to store the data by converting it into a String (text) or int/long first.
This will allow you to easily write and retrieve data, and you should use this.
You can also use the file system to save almost any Java object using serializable, on Internal Storage.
Either way, the data will stay there even if your app is closed or the device is turned off.
When I google "how to make a dictionary", it gives me a great measure of the explanation of "make", which is very helpful. But I need something else, so I put this question here.
I want to make a small project. I want to make a dictionary with java or android. But I don't know how should I organize the words. I have considered a JSON file, a XML file or I can also simply output all the words as ojbects into a file. Could anyone please give me some adivce?
Assuming that you want to be able to read (quickly) values from your dictionary, and maybe update values or create new values then I suggest that you store your dictionary in a Database. For a simple Java database I suggest that you use an embedded Derby Database.
see http://db.apache.org/derby/
Writing Java objects or a List into a text file is ok. But I want to know how I can update or rewrite a object which was written previously without writing objects again. For example, let s assume there is a java.util.List has a set of Objects. and then that list is written to a text file. Then later that file will be read again and get all objects from list and then change one object's value at run time by a java application. Then I don't need to write entire list back to the text file. Instead only the updated object in the list is required to be rewritten or updated in the text file without rewriting the whole list again. Any suggestion, or helpful source with sample codes please.
Take a look at RandomAccessFile. This will let you seek to the place in the file you want, and only update the part that you want to update.
Also take a look at this question on stackoverflow.
Without some fairly complex logic, you won't usually be able to update an object without rewriting the entire file. For example, if one of the objects on your list contains a string "shortstring", and you need to update it with string "muchmuchlongerstring", there will be no space in the file for the longer string without rewriting all the following content in the file.
If you want to persist large object trees to a file and still have the ability to update them, your code will be less buggy and life will be simplified by using one of the many file-based DBs out there, like:
SQLite (see Java and SQLite)
Derby
H2 (disk-based tables)