我想存储一个时间值,需要检索和编辑它。我如何使用SharedPreferences来做到这一点?
当前回答
写:
SharedPreferences preferences = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Authentication_Id",userid.getText().toString());
editor.putString("Authentication_Password",password.getText().toString());
editor.putString("Authentication_Status","true");
editor.apply();
阅读:
SharedPreferences prfs = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_PRIVATE);
String Astatus = prfs.getString("Authentication_Status", "");
其他回答
简单的方法:
保存:
getPreferences(MODE_PRIVATE).edit().putString("Name of variable",value).commit();
检索:
your_variable = getPreferences(MODE_PRIVATE).getString("Name of variable",default value);
最好的实践
创建命名为PreferenceManager的接口:
// Interface to save values in shared preferences and also for retrieve values from shared preferences
public interface PreferenceManager {
SharedPreferences getPreferences();
Editor editPreferences();
void setString(String key, String value);
String getString(String key);
void setBoolean(String key, boolean value);
boolean getBoolean(String key);
void setInteger(String key, int value);
int getInteger(String key);
void setFloat(String key, float value);
float getFloat(String key);
}
如何使用活动/片段:
public class HomeActivity extends AppCompatActivity implements PreferenceManager{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout_activity_home);
}
@Override
public SharedPreferences getPreferences(){
return getSharedPreferences("SP_TITLE", Context.MODE_PRIVATE);
}
@Override
public SharedPreferences.Editor editPreferences(){
return getPreferences().edit();
}
@Override
public void setString(String key, String value) {
editPreferences().putString(key, value).commit();
}
@Override
public String getString(String key) {
return getPreferences().getString(key, "");
}
@Override
public void setBoolean(String key, boolean value) {
editPreferences().putBoolean(key, value).commit();
}
@Override
public boolean getBoolean(String key) {
return getPreferences().getBoolean(key, false);
}
@Override
public void setInteger(String key, int value) {
editPreferences().putInt(key, value).commit();
}
@Override
public int getInteger(String key) {
return getPreferences().getInt(key, 0);
}
@Override
public void setFloat(String key, float value) {
editPreferences().putFloat(key, value).commit();
}
@Override
public float getFloat(String key) {
return getPreferences().getFloat(key, 0);
}
}
注意:用SP_TITLE替换你的SharedPreference键。
例子:
存储字符串在shareperence:
setString("my_key", "my_value");
从shareperence获取字符串:
String strValue = getString("my_key");
希望这对你有所帮助。
SharedPreferences.Editor editor = getSharedPreferences("identifier",
MODE_PRIVATE).edit();
//identifier is the unique to fetch data from your SharedPreference.
editor.putInt("keyword", 0);
// saved value place with 0.
//use this "keyword" to fetch saved value again.
editor.commit();//important line without this line your value is not stored in preference
// fetch the stored data using ....
SharedPreferences prefs = getSharedPreferences("identifier", MODE_PRIVATE);
// here both identifier will same
int fetchvalue = prefs.getInt("keyword", 0);
// here keyword will same as used above.
// 0 is default value when you nothing save in preference that time fetch value is 0.
你需要在AdapterClass或任何其他类中使用SharedPreferences。 那一次只是使用这个声明和使用相同的屁股上面。
SharedPreferences.Editor editor = context.getSharedPreferences("idetifier",
Context.MODE_PRIVATE).edit();
SharedPreferences prefs = context.getSharedPreferences("identifier", Context.MODE_PRIVATE);
//here context is your application context
用于字符串或布尔值
editor.putString("stringkeyword", "your string");
editor.putBoolean("booleankeyword","your boolean value");
editor.commit();
取数据与上面相同
String fetchvalue = prefs.getString("keyword", "");
Boolean fetchvalue = prefs.getBoolean("keyword", "");
使用这个例子简单明了
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.sairamkrishna.myapplication" >
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
public class MainActivity extends AppCompatActivity {
EditText ed1,ed2,ed3;
Button b1;
public static final String MyPREFERENCES = "MyPrefs" ;
public static final String Name = "nameKey";
public static final String Phone = "phoneKey";
public static final String Email = "emailKey";
SharedPreferences sharedpreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ed1=(EditText)findViewById(R.id.editText);
ed2=(EditText)findViewById(R.id.editText2);
ed3=(EditText)findViewById(R.id.editText3);
b1=(Button)findViewById(R.id.button);
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String n = ed1.getText().toString();
String ph = ed2.getText().toString();
String e = ed3.getText().toString();
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString(Name, n);
editor.putString(Phone, ph);
editor.putString(Email, e);
editor.commit();
Toast.makeText(MainActivity.this,"Thanks",Toast.LENGTH_LONG).show();
}
});
}
}
人们推荐使用SharedPreferences的方法有很多。我在这里做了一个演示项目。示例中的关键点是使用ApplicationContext &单个sharedpreferences对象。本示例演示了如何使用SharedPreferences与以下特性
使用singelton类访问/更新SharedPreferences 不需要总是为读/写SharedPreferences传递上下文 它使用apply()而不是commit() Apply()是异步保存,不返回任何东西,它首先在内存中更新值,然后将更改写入磁盘 asynchronusly。 Commit()是同步保存,它根据结果返回true/false。更改以同步方式写入磁盘 适用于android 2.3+版本
使用示例如下:-
MyAppPreference.getInstance().setSampleStringKey("some_value");
String value= MyAppPreference.getInstance().getSampleStringKey();
点击这里获取源代码 &详细的API可以在developer.android.com上找到
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