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Increment shared preference key after adding value

In my app, the user can add a name and an age for multiple people. Most likely it will only be around 2 or 3. I want to store these in shared preferences. I set a counter to keep track of how many people have been stored as well as to manage which key goes with which value. I took the edittext input and put it in a string and then put it into the shared preferences like so, adding on the counter so I know that is the first person and would access the person with "name1".
//this is in the class
public int count = 1;
//this is in the main
SharedPreferences sharedPreferences = getSharedPreferences("registerData", Context.MODE_PRIVATE);
SharedPreferences.Editor myEditor = sharedPreferences.edit();
myEditor.putString("Name"+count, name);
myEditor.putString("Age"+count, age);
Unless I am mistaken, that should put the string "name" into "Name1".
Then I go and try to access it in another activity with...
SharedPreferences sharedPreferences = getSharedPreferences("registerData", Context.MODE_PRIVATE);
String name = sharedPreferences.getString("Name"+count,"");
String age = sharedPreferences.getString("Age"+count,"");
Then i would update the counter before the next person would be added to change the key to "Name2" "Age2", and so on.
Whenever I try to set the strings to a textview, they show up blank. Which means its not the same String to access the key. The putString has to get the "Name1", because even when I try to access the getString("Name",""), it's still blank. Is there something I'm doing wrong or missing. Or there is a better way of doing this? Thanks.

SharedPreferences sharedPreferences = getSharedPreferences("registerData",Context.MODE_PRIVATE);
SharedPreferences.Editor myEditor = sharedPreferences.edit();
myEditor.putString("Name"+count, name);
myEditor.putString("Age"+count, age);
myEditor.apply();//returns nothing,don't forgot to commit changes
also you can use
myEditor.commit() //returns true if the save works, false otherwise.

Is there something I'm doing wrong or missing. Or there is a better
way of doing this?
If SharedPreferences key names are dynamic then you should use SharedPreferences.getAll() which return all keys available in selected preference:
Map<String, ?> allKeys = sharedPreferences.getAll();
Now iterate through allKeys to check key names and get values from Map.Entry related to key like:
for (Map.Entry<String, ?> entry : allKeys.entrySet()) {
Log.v("TAG","Key Name :" entry.getKey());
Log.v("TAG","Key Value :" entry.getValue());
}

You have to call apply() on the shared preference editor after making changes.
...
myEditor.apply();
Shared preferences however, are not meant to store content related data. Consider using more appropriate solutions like a database.

How to get all keys of SharedPreferences programmatically in Android?

How to get all keys in SharedPreferences, not the value of the preference just key only?
prefA = getSharedPreferences("MyAttack", MODE_PRIVATE);
prefB= getSharedPreferences("MySkill", MODE_PRIVATE);

SharedPreferences has the method getAll() that returns a Map<String, ?> . From the Map you can retrieve easily the keys with keySet() and the key/value mappings with entrySet():
Map<String, ?> allEntries = prefA.getAll();
for (Map.Entry<String, ?> entry : allEntries.entrySet()) {
Log.d("map values", entry.getKey() + ": " + entry.getValue().toString());
}

What you can do is use getAll() method of SharedPreferences and get all the values in Map and then you can easily iterate through them:
Map<String,?> keys = prefs.getAll();
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " + entry.getValue().toString());
}
For more, you can check PrefUtil.java's dump() implementation with this link.

Use the getAll() method of android.content.SharedPreferences.
Map<String, ?> map = sharedPreferences.getAll();

Kotlin will allow you to get all your SharedPreferences keys with just one line by using Map.
Cheers mate 🎉
val sharedPreferences = context.getSharedPreferences("SHARED_PREFERENCES", Context.MODE_PRIVATE)
val sharedPreferenceIds = sharedPreferences.all.map { it.key } //returns List<String>

Check out the below code for getAll() method
Map<String, ?> prefsMap = prefA.getAll();
for (Map.Entry<String, ?> entry: prefsMap.entrySet()) {
Log.v("SharedPreferences", entry.getKey() + ":" +
entry.getValue().toString());
}

After reading #Delacrix response and playing with the Kotlin-way (tested in Kotlin 1.3.11) of retrieving the keys, I found out an even shorter version for getting the keys (or even the values):
val prefsA = context.getSharedPreferences("MyAttack", Context.MODE_PRIVATE)
val prefsAIDs = sharedPreferences.all.keys //returns MutableSet<String>
The same way, you can access only the values via sharedPreferences.all.values (even tho is not what you asked in your question, might be a useful for other readers).

Although #Blackbelt's answer is quite popular here, I think it is not actually targeting the question. (It is not suprising since the question mixes up the terminology of preferences names and keys.) I guess the question is how to find out which shared preferences instances have been created - which can be of interest if the names are created dynamically.
Here are two strategies for that:
create another shared preferences "meta" instance where all created shared prefences instances are registered by adding a key/value pair for it to the meta prefs - with the key being the shared prefences name and the value being any value e.g. true.
getSharedPreferences( DYNAMIC_PREFS_NAME, 0 )
.edit().put*(*).apply();
getSharedPreferences( "meta_prefs_index", 0 )
.edit().putBoolean( DYNAMIC_PREFS_NAME, true).apply();
To obtain all shared prefences created by you, use the meta prefs and follow the answer of #Blackbelt.
shared preferences have a backup file, which is stored in folder /data/data/YOUR_PACKAGE_NAME/shared_prefs with name YOUR_PREFS_NAME.xml
So you can look into that directory for your shared preferences files. But be careful, there might be shared preferences files that were not created by your logic! Therfore I would stick with the first approach.

How to avoid adding duplicate values in shared preferences in android?

In android, i am adding string values using shared preferences, but i want to compare the value which i am going to add to shared preferences with values which are already stored in shared preferences to avoid adding duplicate values, but i am not getting how to do this?
or is there any alternate method to avoid adding duplicate values in shared preferences?
I am adding string values using following code
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
Editor editor = sharedpreferences.edit();
editor.putString(Name, s);
editor.commit();

In android you cannot really have duplicate value in sharedPreference because every time you change or modify a value on sharedPreference it will replace the previous with the current. So since every instance of it has a single unique key, which mean it will always be unique (in my experience every time i messed up with this keys like giving the same name key for both an Int and boolean for example i end up crashing the app or having some kind of exception)
If im wrong i hope someone else will correct me and provide you with a better answer!

I don't know whether I'm understanding your question quite well or not, but Android's SharedPreferenceshas it's own contains to check if a a key already exists or not.
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
if (sharedpreferences.contains(NAME)) //It already contains NAME key
On the other hand, if your worries are about a single key's value not to be repeated, just read it before storing the new value and compare themselves, no more.
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
if (!sharedpreferences.getString(NAME, "").equals(s)) {
// It does not have the same value, store 's'
sharedpreferences
.edit();
.putString(NAME, s);
.commit();
}
However, in this particular case I wouldn't perform this verification, just overwrite the value and that's it, as it always gonna be the same.

First get String value from SharedPreferences as oldvalue then compare with newvalue which you want to store. If String not match then save newvalue in SharedPreferences.
Try something like this
String str_newvalue = "new string here";
SharedPreferences sharedpref = this.getSharedPreferences(this.getPackageName(), context.MODE_PRIVATE);
String str_oldvalue = sharedpref.getString("key", "");
if (!str_newvalue.equals(str_oldvalue)) {
sharedpref.edit().putString("key", str_newvalue).commit();
}

Do this
SharedPreferences prefs = getPreferences(MODE_PRIVATE);
String restoredText = prefs.getString("text", null);
if(restoredText.matches(your string))
{
// do nothing
}
else
{
//save your data
}
}

Get Strings from ArrayList and save in Shared Preferences

I have an ArrayList that can contain 1 to 15 strings. Those strings need to be saved in my shared preferences, now I know how to iterate trough the array to get the strings. What I don't know, is there a clean way to dynamically add the strings to my shared preferences file? I could do this on a sluggish way by creating 15 strings and using an if statement to fill the shared preference, but I would like to know if there is a better way.
Thank you.

If its about naming, you can use something like this:
public static final String mPrefix = "mArray";
SharedPreferences prefs;
prefs = this.getSharedPreferences("PREF", 0);
prefsEditor = appSharedPrefs.edit();
//mAL is your ArrayList
for(int i=0; i<mAl.size(); i++){
prefsEditor.putString(mPrefix + "-" + i, mAl.get(i));
}
prefsEditor.commit();

You can use the putStringSet method available in SharedPreferences.Editor to store string arrays. For example:
String[] array = new String[]{"this", "is", "a", "string", "array"};
SharedPreferences.Editor edit = sharedPrefs.edit();
edit.putStringSet("myKey", new HashSet<String>(Arrays.asList(array)));
edit.commit();
Or if your API is below 11 then you may convert your string array into a single string and save it just like an ordinary string. For example:
edit.putString("myKey", TextUtils.join(",", array));
and later use the following to rebuild your array from string:
array = TextUtils.split(sharedPrefs.getString("myKey", null), ",");

Mainly to edit the shared prefernces data you need to take the Editor Object from it so you could edit it freely so to put data in it:
SharedPrefernces preferences = mContext.getSharedPreferences(MODE_PRIVATE);
Editor prefEditor = preferences.edit();
prefEditor.putString("this is a key object","this is value of the key");
You can also put inside different kinds of object for example : boolean , int , float , double and etc....
Just look up the editor class in android developers website...
In order to read the data from the sharedPrefrences it is even more simplier
SharedPrefrences pref = mContext.getSharedPreferences(MODE_PRIVATE);
pref.getString("the key of the value");

how to convert sharedpreferences data to hashmap in android

I have created shared preferences as below:
SharedPreferences preferences =
getSharedPreferences("PREF_FILE_NAME",Activity.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
and put the value as shown below:
editor.putLong(parser.nextText().toString(), i);
where I increase the value.
It is stored fine.
Now I want to retrieve that value because I want to show it in table layout, but I don't know how.
So what is easiest way to do this? Any advice?

Iterating Preferences using Map.
Map<String,?> keys = prefs.getAll();
Then you can easily iterate using Entry,
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " +
entry.getValue().toString());
}