懒得再翻译,这段应该很好理解,直接将Dev Guide中复制过来。
The SharedPreferences
class provides a general framework that allows you to save and retrieve persistent key-value pairs of primitive data types. You can use SharedPreferences
to save any primitive data: booleans, floats, ints, longs, and strings. This data will persist across user sessions (even if your application is killed).
To get a SharedPreferences
object for your application, use one of two methods:
getSharedPreferences()
- Use this if you need multiple preferences files identified by name, which you specify with the first parameter.
getPreferences()
- Use this if you need only one preferences file for your Activity. Because this will be the only preferences file for your Activity, you don't supply a name.
To write values:
- Call
edit()
to get a SharedPreferences.Editor
.
- Add values with methods such as
putBoolean()
and putString()
.
- Commit the new values with
commit()
To read values, use SharedPreferences
methods such as getBoolean()
and getString()
.
Here is an example that saves a preference for silent keypress mode in a calculator:
1public class Calc extends Activity {
2 public static final String PREFS_NAME = "MyPrefsFile";
3
4 @Override
5 protected void onCreate(Bundle state){
6 super.onCreate(state);
7 . . .
8
9 // Restore preferences
10 SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
11 boolean silent = settings.getBoolean("silentMode", false);
12 setSilent(silent);
13 }
14
15 @Override
16 protected void onStop(){
17 super.onStop();
18
19 // We need an Editor object to make preference changes.
20 // All objects are from android.context.Context
21 SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
22 SharedPreferences.Editor editor = settings.edit();
23 editor.putBoolean("silentMode", mSilentMode);
24
25 // Commit the edits!
26 editor.commit();
27 }
28}