Android 来自不同活动的 SharedPreferences
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/11316560/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
SharedPreferences from different activity
提问by user1390816
I load from activity A the SharedPreferences in following way:
我通过以下方式从活动 A 加载 SharedPreferences：
private void SavePreferences(String key, String value){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
At activity B I want to load the SharedPreferences. Following was a NullPointerException:
在活动 BI 想要加载 SharedPreferences。以下是 NullPointerException：
private void LoadPreferences(){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
data = sharedPreferences.getString("name", "08:00") ;
}
If I try following, I get this compilation error: "No enclosing instance of the type A is accessible in scope"
如果我尝试以下操作，则会收到此编译错误：“在范围内无法访问类型 A 的封闭实例”
private void LoadPreferences(){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(A.this);
data = sharedPreferences.getString("name", "08:00") ;
}
How can I access the data?
如何访问数据？
回答by ρяσ?ρ?я K
use getApplicationContext()instead of thisin both Activities as:
在两个活动中使用getApplicationContext()代替this：
In activity A the SharedPreferences in following way:
在活动 A 中， SharedPreferences 以下列方式：
private void SavePreferences(String key, String value){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
Intent sd=new Intent(this,Secongtess.class);
startActivity(sd);
}
and in Activity B get Value as:
并在活动 B 中获得价值为：
private void LoadPreferences(){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
String data = sharedPreferences.getString("name", "08:00") ;
Toast.makeText(this,data, Toast.LENGTH_LONG).show();
}
because as doc says:
因为正如医生所说：
getDefaultSharedPreferences(Context context):
getDefaultSharedPreferences(上下文上下文)：
Gets a SharedPreferences instance that points to the default file that is used by the preference framework in the given context.
获取一个 SharedPreferences 实例，该实例指向给定上下文中首选项框架使用的默认文件。
回答by Goofy
To store values in shared preferences:
要将值存储在共享首选项中：
SharedPreferences preferences==PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor=preferences.edit();
editor.putString("Name","Harneet");
editor.commit();
To retrieve values from shared preferences:
要从共享首选项中检索值：
SharedPreferences preferences==PreferenceManager.getDefaultSharedPreferences(this);
String name=preferences.getString("Name","");
if(!name.equalsIgnoreCase(""))
{
name=name+" Sethi"; /* Edit the value here*/
}
To edit data from sharedpreference
从共享首选项编辑数据
SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
editor.putString("text", mSaved.getText().toString());
editor.putInt("selection-start", mSaved.getSelectionStart());
editor.putInt("selection-end", mSaved.getSelectionEnd());
editor.commit();
To retrieve data from shared preference
从共享首选项中检索数据
SharedPreferences prefs = getPreferences(MODE_PRIVATE);
String restoredText = prefs.getString("text", null);
if (restoredText != null)
{
//mSaved.setText(restoredText, TextView.BufferType.EDITABLE);
int selectionStart = prefs.getInt("selection-start", -1);
int selectionEnd = prefs.getInt("selection-end", -1);
/*if (selectionStart != -1 && selectionEnd != -1)
{
mSaved.setSelection(selectionStart, selectionEnd);
}*/
}
