Here is the code i tried:
SharedPreferences.Editor prefEditor = sharedPreferences.edit();
int balance = sharedPreferences.getInt("balance", 0);
prefEditor.putInt(balance, balance1);
prefEditor.commit();
From the comments beneath your question, I understand that you simply wish to update a value within sharedpreferences. Your first line is fine:
SharedPreferences.Editor prefEditor = sharedPreferences.edit();
This next line is then optional. Use it if you want to get at the existing value held under the key "balance" before you replace it. Otherwise it is not required and has no bearing on the 3rd line of code which replaces "balance" with a new value.
int balance = sharedPreferences.getInt("balance", 0);
Then I think your 3rd line should become:
prefEditor.putInt("balance", balance1);
That will replace the value held under the key "balance" with whatever value is held in balance1. Notice the quotes around "balance" that you did not have in your original code.
Related
I came across an Android Question as follows. The result is confusing me.
SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0); // 0 - for private mode
SharedPreferences.Editor editor = pref.edit();
editor.putString("1", "2"); // Storing string
editor.putString("3", "4 "); // Storing string
editor.commit();
System.out.println("pref.getString() = " + pref.getString("2","3"));
Answer: pref.getString() = 3.
How does the shared preference prints this value ? Can someone please explain this ?
The first argument to get...() is the shared preferences key. The second argument is the default value to return in case there's no value by that key.
Assuming no other code has put a value with key "2" in this shared preferences file, the default value of "3" is returned when calling pref.getString("2","3").
The SharedPreference object does not print anything.
The sharedPreference stores data in key-value pairs in an xml file named MyPref in your case:
getApplicationContext().getSharedPreferences("MyPref", 0);
You put the value you want to store by calling the putXX method on the editor object obtained from the pref object by calling edit() on it:
SharedPreferences.Editor editor = pref.edit();
** putXX means put[some kind of primitive data] like int float String.
When you call putString you supply a key as the first parameter and the String value in this case as the second parameter:
editor.putString("1", "2"); // Storing string
editor.putInt("myInt", 2); // Storing integer
The commit method writes the data.
editor.commit();
The getString retrieve a string value for a key given as the first parameter and if they are no entry a default value returned which is the second parameter in this case "3":
String myValue = pref.getString("2","3")
The printing performed by calling:
System.out.println(myValue);
editor.putString("1", "2") - first argument is KEY, second argument is value.
pref.getString("2","3") - first argument is KEY, second argument is Default value (in case if such key isn't present).
In your case you've put two strings - 2 and 4 in keys 1 and 3 accordingly.
When you are trying to read string with key 2 - it is missing. So default value (3) is printed
P.s. you are using keys very similar to values - Strings containing numbers. Just put more readable keys and thing will get clearer.
Android has a page that it's very clean. Shared Preferences getString()
This method has two parameters :
key
The name of the preference to retrieve.
defValue
Value to return if this preference does not exist.
This value may be null.
So if you have this in your SharedPreferences
editor.putString("1", "2"); // Storing string
editor.putString("3", "4 "); // Storing string
And you are doing : pref.getString("2","3")
You are looking for the SharedPreferences key with a value of "2", and if it doesn't find anything you'll get "3" as a default value.
I use the following helper to save user input to sharedpreference:
protected void storeData(SharedPreferences.Editor editor,
String key, EditText et) {
String content = et.getText().toString();
if ("".equals(content)||" ".equals(content)) {
editor.remove(key);
} else {
editor.putString(key, content);
}
}
then
number1 = (EditText)findViewById(R.id.number1);
SharedPreferences sharedPreferences = getSharedPreferences("Database", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
storeData(editor,"number1", number1);
editor.commit();
I wish to ask if how can I retrieve that value as a integer, then use it for some calculation.
I been searching and found this , found that they use editor.putInt(key,content);
But is that possible to extract the value as integer straight from my method?
thank you.
Your storeData() method is setting a string (putString()). Shared prefs store typed values distinctly different. That is, you cannot put "1" as a string then get it our later as an integer.
You need to use put/getInt() consistently. Alternatively you could store it as a string, and again consistently get it as a string and coerce it to an int as you need.
Your really should be using putInt(), but you can also use Integer.parseInt("some string") to convert your String value to an integer.
Use editor.commit() inside the else part
A suggestion:
use editor.apply() instead of editor.commit() as commit handles the job in foreground whereas apply handles that asynchronously.
I know, the question has been asked long time agao. I came up with similar situation. So, the might help someone in the future.
//for integer values
port = (EditText) findViewById(R.id.devicePort);
int devicePort = Integer.parseInt(port.getText().toString());
editor.putInt(getString(R.string.devicePort), devicePort);
editor.apply();
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.
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
}
}
my problem: When I want to save a sharedPreference and restart the app, it doesnt load the right value..
My code:
int punkteint = 0;
TextView test1;
String points;
private static String SHARED_PREF_ID = "0";
public void onCreate(Bundle savedInstanceState) {
test1 = (TextView) findViewById(R.id.test1);
SharedPreferences load = getSharedPreferences(SHARED_PREF_ID, 0);
points = load.getString("punkte", "0");
points = SHARED_PREF_ID;
test1.setText(points);
mehrPunkte();
}
public void mehrPunkte() {
punkteint++;
SHARED_PREF_ID = Integer.toString(punkteint);
SharedPreferences load = getSharedPreferences(SHARED_PREF_ID, MODE_PRIVATE);
points = load.getString("punkte", "0");
points = SHARED_PREF_ID;
test1.setText(points);
SharedPreferences save = getSharedPreferences(SHARED_PREF_ID, MODE_PRIVATE);
save.edit().putString("punkte", SHARED_PREF_ID).commit();
}
What did I do wrong here?
Hope you can help me
Not sure what you're trying to do here:
points = load.getString("punkte", "0");
points = SHARED_PREF_ID;
test1.setText(points);
Basically, what you've told it to do is "load punkte's value into points, then load SHARED_PREF_ID into points". That means points will always be equal to SHARED_PREF_ID here. Remove the lines that say "points = SHARED_PREF_ID;" and you will probably have more success.
Additionally, I would not change SHARED_PREF_ID's value. Make it a final String and give it some unique value (like "punkte_prefs").
Lastly, I would take a look at the documentation which has great examples, and #Kaediil's answer as well (as he caught something I missed...).
This line:
save.edit().putString("punkte", SHARED_PREF_ID).commit();
is saving SHARED_PREF_ID as the value of punkte. So, it will always be 0. Maybe you mean:
save.edit().putString("punkte", String.valueOf(punkteint)).commit();
or maybe:
save.edit().putString("punkte", String.valueOf(points)).commit();
I am not sure what you are trying to actually save.
Oh and you are resettiong the value as soonas you get it from the shared prefs:
points = load.getString("punkte", "0");
points = SHARED_PREF_ID;
Don't do the second line.
Not sure. What your doing should work but I would use this instead
SharedPreferences.Editor prefEditor = save.edit();
prefEditor.putString("blah", blah);
PredEditor.commit()
Do the save in onPause and load in onResume. Could help if the data is meant to change thrpught the activity.
I think you've gotten yourself all twisted up here.
private static String SHARED_PREF_ID = "0";
...
SharedPreferences load = getSharedPreferences(SHARED_PREF_ID, 0);
points = load.getString("punkte", "0");
points = SHARED_PREF_ID;
These lines read shared preferences from a file named "0". Is that what you wanted? That's a not-very-useful name for a file. The next line reads a string value named "punkte" into the variable "points" and then immediately discards that value and replaces it with "0".
punkteint++;
SHARED_PREF_ID = Integer.toString(punkteint);
SharedPreferences load = getSharedPreferences(SHARED_PREF_ID, MODE_PRIVATE);
These lines increment a counter, use it to generate a whole new filename, and loads a whole new set of preferences from that file. Again, you load "points" from those preferences and immediately discard the value, setting it to this new filename.
SharedPreferences save = getSharedPreferences(SHARED_PREF_ID, MODE_PRIVATE);
save.edit().putString("punkte", SHARED_PREF_ID).commit();
These lines re-load the preferences from that new file again and writes the filename into the "punkte" value.
It looks like you're deliberately generating a series of preferences files, each of which contains its own name under the value "punkte".
When you next run the app, you'll go back to reading preferences from file "0", getting the same value you got the first time: "0"
It would help if you told us what you were actually trying to do.