Android: How to keep current state (Using SharedPreferences method)

1. Save Data
    SharedPreferences shprefs
                          = getSharedPreferences((String)"GroupSMSApp", MODE_PRIVATE);
    SharedPreferences.Editor preeditor = shprefs.edit();
    preeditor.putString((String)"s_prefix", mPrefix);
    preeditor.putString((String)"s_postfix", mPostfix);
    preeditor.putString((String)"s_message", mMessage);
    preeditor.commit();


2. Getting Data

    SharedPreferences prefs =
               getApplicationContext().getSharedPreferences((String)"GroupSMSApp", 0);
               
    String mStrEditPrefix  = prefs.getString((String)"s_prefix", "");
    if(mStrEditPrefix != null)
        mEditPrefix.setText(mStrEditPrefix);
       
    String mStrEditPostfix = prefs.getString((String)"s_postfix", "");
    if(mStrEditPostfix != null)
        mEditPostfix.setText(mStrEditPostfix);
       
    String mStrEditMessage = prefs.getString((String)"s_message", "");
    if(mStrEditMessage != null)
        mEditMessage.setText(mStrEditMessage);

3. Saved Location
    data/data/PACAKGE_NAME/shared_prefs/GroupSMSApp.xml

From : http://developer.android.com

public interface

SharedPreferences

android.content.SharedPreferences

Class Overview

---

Interface for accessing and modifying preference data returned by getSharedPreferences(String, int). For any particular set of preferences, there is a single instance of this class that all clients share. Modifications to the preferences must go through an SharedPreferences.Editor object to ensure the preference values remain in a consistent state and control when they are committed to storage. Objects that are returned from the various get methods must be treated as immutable by the application.

Note: currently this class does not support use across multiple processes. This will be added later.

Developer Guides

For more information about using SharedPreferences, read the Data Storage developer guide.

See Also

• getSharedPreferences(String, int)

Summary

---

Nested Classes
interface	SharedPreferences.Editor	Interface used for modifying values in a SharedPreferences object.
interface	SharedPreferences.OnSharedPreferenceChangeListener	Interface definition for a callback to be invoked when a shared preference is changed.

Public Methods
abstract boolean	contains(String key) Checks whether the preferences contains a preference.
abstract SharedPreferences.Editor	edit() Create a new Editor for these preferences, through which you can make modifications to the data in the preferences and atomically commit those changes back to the SharedPreferences object.
abstract Map<String, ?>	getAll() Retrieve all values from the preferences.
abstract boolean	getBoolean(String key, boolean defValue) Retrieve a boolean value from the preferences.
abstract float	getFloat(String key, float defValue) Retrieve a float value from the preferences.
abstract int	getInt(String key, int defValue) Retrieve an int value from the preferences.
abstract long	getLong(String key, long defValue) Retrieve a long value from the preferences.
abstract String	getString(String key, String defValue) Retrieve a String value from the preferences.
abstract Set<String>	getStringSet(String key, Set<String> defValues) Retrieve a set of String values from the preferences.
abstract void	registerOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener) Registers a callback to be invoked when a change happens to a preference.
abstract void	unregisterOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener) Unregisters a previous callback.

Public Methods

---

public abstract boolean contains (String key)

Added in API level 1

Checks whether the preferences contains a preference.

Parameters

key	The name of the preference to check.

Returns

• Returns true if the preference exists in the preferences, otherwise false.

public abstract SharedPreferences.Editor edit ()

Added in API level 1

Create a new Editor for these preferences, through which you can make modifications to the data in the preferences and atomically commit those changes back to the SharedPreferences object.

Note that you must call commit() to have any changes you perform in the Editor actually show up in the SharedPreferences.

Returns

• Returns a new instance of the SharedPreferences.Editor interface, allowing you to modify the values in this SharedPreferences object.

public abstract Map<String, ?> getAll ()

Added in API level 1

Retrieve all values from the preferences.

Note that you must not modify the collection returned by this method, or alter any of its contents. The consistency of your stored data is not guaranteed if you do.

Returns

• Returns a map containing a list of pairs key/value representing the preferences.

Throws

NullPointerException

public abstract boolean getBoolean (String key, boolean defValue)

Added in API level 1

Retrieve a boolean value from the preferences.

Parameters

key	The name of the preference to retrieve.
defValue	Value to return if this preference does not exist.

Returns

• Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a boolean.

Throws

ClassCastException

public abstract float getFloat (String key, float defValue)

Added in API level 1

Retrieve a float value from the preferences.

Parameters

key	The name of the preference to retrieve.
defValue	Value to return if this preference does not exist.

Returns

• Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a float.

Throws

ClassCastException

public abstract int getInt (String key, int defValue)

Added in API level 1

Retrieve an int value from the preferences.

Parameters

key	The name of the preference to retrieve.
defValue	Value to return if this preference does not exist.

Returns

• Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not an int.

Throws

ClassCastException

public abstract long getLong (String key, long defValue)

Added in API level 1

Retrieve a long value from the preferences.

Parameters

key	The name of the preference to retrieve.
defValue	Value to return if this preference does not exist.

Returns

• Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a long.

Throws

ClassCastException

public abstract String getString (String key, String defValue)

Added in API level 1

Retrieve a String value from the preferences.

Parameters

key	The name of the preference to retrieve.
defValue	Value to return if this preference does not exist.

Returns

• Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a String.

Throws

ClassCastException

public abstract Set<String> getStringSet (String key, Set<String> defValues)

Added in API level 11

Retrieve a set of String values from the preferences.

Note that you must not modify the set instance returned by this call. The consistency of the stored data is not guaranteed if you do, nor is your ability to modify the instance at all.

Parameters

key	The name of the preference to retrieve.
defValues	Values to return if this preference does not exist.

Returns

• Returns the preference values if they exist, or defValues. Throws ClassCastException if there is a preference with this name that is not a Set.

Throws

ClassCastException

public abstract void registerOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)

Added in API level 1

Registers a callback to be invoked when a change happens to a preference.

Parameters

listener	The callback that will run.

See Also

• unregisterOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener)

public abstract void unregisterOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)

Added in API level 1

Unregisters a previous callback.

Parameters

listener	The callback that should be unregistered.

See Also

• registerOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener)