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Android - Does R.Resource ID changes in runtime

I have number of drawables to select in a View. When the user selects one of the drawable and on next time when the app is launch , I have to show only the selected drawable.
Is it good to store the Resource ID in shared preference and retrieve the selected drawable using Resource ID next time when the app is launched.?

All the R class related ids are generated at compile time so they won't change at runtime. There's nothing stopping you from storing this IDs in SharedPreferences, however, there's no gain whatsoever. It's almost always faster just to reference the R.drawable.x related id.

I know this is an older question, but I'd advise AGAINST storing the values in SharedPreferences.
When you release a newer version of the app, it's re-compiled. There is no guarantee, that the old value of let's say R.drawable.ic_example has the same value when drawables have been added/removed to the updated application. Therefore the stored value could no longer match with the Drawable asset you expect.

Best way to store Resource id in Database on Android

In my app i want to be able to store resource id of some icons in database. I suppose it is not save to do, cause in the later stages (application upgrades) i may want to add new icons to the app, so all id's may change? What is the best practice to store resource in case i do not want to store icons as blobs?
As an example, let's say i have a game 1.0, where i let user to choose an avatar for his character from a list of avatars. I want to store this avatars id in DB and be sure that if i add more avatars in game 1.1 - user will still see his choice.

The best way (in my opinion) is to store the resource entry name.
String iconName = getResources().getResourceEntryName(R.drawable.your_icon);
So your SQLite database column where you want to store the icon will have type TEXT. You're right that storing resource IDs is a bad practice because they're recreated when you compile the app, so you can't rely on them not changing (I learned this the hard way, all my app's icons got messed up).
To get the resource ID from the String when you need it, call
int resID = getResources().getIdentifier(iconName, "drawable", getPackageName());
Note that both getResources() and getPackageName() are methods from Context, so you need to have reference to your application/activity Context to be able to call these methods.

Formatting fileds using android views

Is there any good simple way to format fields as I want.
I'd like to separate field value from field text. For example, I'd like to group number by 4, so when I set field's value to 123456789 it would show as 1 2345 6789, but when I get value I'll get number without spaces (123456789).
I think, this is the way widgets works on other tools, i.e. .Net VS. I can set there some mapping, formats and so on, so what is shown depends on value and format/mapping.
In android this must be done for passwords fields. It has text as value, but it shows some dots (value is mypassword and field shows **********).

I guess you just want to display the number in nice format, please use the APIs provided by PhoneNumberUtils.
static String formatNumber(String source)
static void formatNumber(Editable text, int defaultFormattingType)
You could set the formatted string to the text view for displaying nicely. But the saved content is still the raw content without any format.
Please refer to the SDK document at http://developer.android.com/reference/android/telephony/PhoneNumberUtils.html

Android: image ID in layout directory

I have 100 images in my application of different cities and I want to divide these pictures in different groups, lets say in evening, morning, sunny, raining etc…
We know that when we call an image from layout folder by calling R.layout.image_1, android generates integer number for each image
For example:
R.layout.image_1 (223344), R.layout.image_2 (556677),
R.layout.image_3 (778899),
I can create one table having evening, morning fields and I can assign group of pictures to each of them with integer IDs which are (223344,556677) and I can call evening or morning group and i can display all images related to these group.
My question is: Does Android generate same number every time. Are these numbers are fixed? When ever the application runs.
If its true then upper idea will work for me. If this idea is incorrect then kindly guide me what is the decent approach to handle hundreds of PNGs in application.

Those numbers are not fixed. R will be regenerated and can have completely different numbers if you change something. That is why when comparing ids, you compare by the name instead.
Eg instead of
if (i == 223344)
do
if (i == R.layout.image_1)
Since R.layout.image_1 references the integer id, the name won't change (unless you change the layout xml name.
If you want to get a resource id dynamically (by a string representing the name), you should have a look at this method - Resources#getIdentifier().

First of all we generally put images in the drawable folder.
Does Android generate same number every time?
No.
Are these numbers fixed whenever the application runs?
Yes.
In fact, once your project is built, the ids will remain the same for that same build.
In other words for a certain generated APK file, the ids won't change.
So how can you take advantage of that to group your resources?
You could have a static int array that holds the ids:
public static final int[] IMAGES_MORNING = {R.drawable.morning0, R.drawable.morning1, etc};
public static final int[] IMAGES_EVENING = {R.drawable.evening0, R.drawable.evening1, etc};
Although a more structured method would be to store them in a database on your app's first launch.
Or you could use what A--C suggests:
For example to get all the ids of morning images
for(int i = 0; i < numberOfMorningImages ; i++){
int id = getResources().getIdentifier("morning" + i, "drawable", getPackageName());
// do something with the id
}

No, there's no guarantee that integers will be the same every time, so the solution you've described won't work. Unfortunately, there's no proper way to group drawables inside the res/drawable folder. As a workaround, you can store them inside the assets folder, where you can group them as you like. However, Android won't be able to handle different resolutions this way. The choice is up to you. Hope this helps.

Is there simple way to create user defaults values for TextView in Android?

I'm looking for simple way to create user defaults values for TextView in Android: I need the standart solution that user is seeing the previous value, that was entered by him to the TextView. Sure, there is way to store value of TextView at somewhere and then read it again while starting activity, but, may be, there is any simple tool to get what I wish ?

You can use SharedPreferences to store previous values and then get previous values from shared preferences to set as default values

Just to get your question correctly:
You want to present the values the user selected/set in his last visit?
You can save those values in the SharedPreferences - That's what they're made for.
You can give the google prediction api a try.