如何在 Android 中使用 SharedPreferences 来存储、获取和编辑值

How to use SharedPreferences in Android to store, fetch and edit values

提问by Muhammad Maqsoodur Rehman

I want to store a time value and need to retrieve and edit it. How can I use SharedPreferencesto do this?

我想存储一个时间值，需要检索和编辑它。我怎样才能SharedPreferences做到这一点？

回答by naikus

To obtain shared preferences, use the following method In your activity:

要获取共享首选项，请在您的活动中使用以下方法：

SharedPreferences prefs = this.getSharedPreferences(
      "com.example.app", Context.MODE_PRIVATE);

To read preferences:

要阅读首选项：

String dateTimeKey = "com.example.app.datetime";

// use a default value using new Date()
long l = prefs.getLong(dateTimeKey, new Date().getTime()); 

To edit and save preferences

编辑和保存首选项

Date dt = getSomeDate();
prefs.edit().putLong(dateTimeKey, dt.getTime()).apply();

The android sdk's sample directory contains an example of retrieving and storing shared preferences. Its located in the:

android sdk 的示例目录包含检索和存储共享首选项的示例。它位于：

<android-sdk-home>/samples/android-<platformversion>/ApiDemos directory

Edit==>

编辑==>

I noticed, it is important to write difference between commit()and apply()here as well.

我注意到，在这里写下commit()和之间的差异也很重要apply()。

commit()return trueif value saved successfully otherwise false. It save values to SharedPreferences synchronously.

commit()true如果值保存成功则返回，否则返回false。它将值同步保存到 SharedPreferences 。

apply()was added in 2.3 and doesn't return any value either on success or failure. It saves values to SharedPreferences immediately but starts an asynchronouscommit. More detail is here.

apply()在 2.3 中添加并且在成功或失败时不返回任何值。它立即将值保存到 SharedPreferences，但会启动异步提交。更多细节在这里。

回答by Harneet Kaur

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.apply();

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*/
}

回答by DeRagan

To editdata from sharedpreference

要编辑从数据sharedpreference

 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.apply();

To retrievedata from sharedpreference

为了获取从数据sharedpreference

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);
  }*/
}

Edit

编辑

I took this snippet from API Demo sample. It had an EditTextbox there . In this contextit is not required.I am commenting the same .

我从 API Demo 示例中获取了这个片段。那里有一个EditText盒子。在这context不是必需的。我评论相同。

回答by stackoverflow

To Write :

来写 ：

SharedPreferences preferences = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_WORLD_WRITEABLE);
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();

To Read :

阅读 ：

SharedPreferences prfs = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_PRIVATE);
String Astatus = prfs.getString("Authentication_Status", "");

回答by ArcDare

Easiest way:

最简单的方法：

To save:

保存：

getPreferences(MODE_PRIVATE).edit().putString("Name of variable",value).commit();

To retrieve:

检索：

your_variable = getPreferences(MODE_PRIVATE).getString("Name of variable",default value);

回答by Jorgesys

Setting values in Preference:

在首选项中设置值：

// MY_PREFS_NAME - a static String variable like: 
//public static final String MY_PREFS_NAME = "MyPrefsFile";
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
 editor.putString("name", "Elena");
 editor.putInt("idName", 12);
 editor.commit();

Retrieve data from preference:

从首选项中检索数据：

SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE); 
String restoredText = prefs.getString("text", null);
if (restoredText != null) {
  String name = prefs.getString("name", "No name defined");//"No name defined" is the default value.
  int idName = prefs.getInt("idName", 0); //0 is the default value.
}

more info:

更多信息：

Using Shared Preferences

使用共享首选项

Shared Preferences

共享偏好

回答by Magesh Pandian

Singleton Shared Preferences Class. it may help for others in future.

单例共享首选项类。将来可能会对其他人有所帮助。

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;

public class SharedPref
{
    private static SharedPreferences mSharedPref;
    public static final String NAME = "NAME";
    public static final String AGE = "AGE";
    public static final String IS_SELECT = "IS_SELECT";

    private SharedPref()
    {

    }

    public static void init(Context context)
    {
        if(mSharedPref == null)
            mSharedPref = context.getSharedPreferences(context.getPackageName(), Activity.MODE_PRIVATE);
    }

    public static String read(String key, String defValue) {
        return mSharedPref.getString(key, defValue);
    }

    public static void write(String key, String value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putString(key, value);
        prefsEditor.commit();
    }

    public static boolean read(String key, boolean defValue) {
        return mSharedPref.getBoolean(key, defValue);
    }

    public static void write(String key, boolean value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putBoolean(key, value);
        prefsEditor.commit();
    }

    public static Integer read(String key, int defValue) {
        return mSharedPref.getInt(key, defValue);
    }

    public static void write(String key, Integer value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putInt(key, value).commit();
    }
}

Simply call SharedPref.init()on MainActivityonce

只需拨打SharedPref.init()上MainActivity一次

SharedPref.init(getApplicationContext());

To Write data

写入数据

SharedPref.write(SharedPref.NAME, "XXXX");//save string in shared preference.
SharedPref.write(SharedPref.AGE, 25);//save int in shared preference.
SharedPref.write(SharedPref.IS_SELECT, true);//save boolean in shared preference.

To Read Data

读取数据

String name = SharedPref.read(SharedPref.NAME, null);//read string in shared preference.
int age = SharedPref.read(SharedPref.AGE, 0);//read int in shared preference.
boolean isSelect = SharedPref.read(SharedPref.IS_SELECT, false);//read boolean in shared preference.

回答by fidazik

To store information

存储信息

SharedPreferences preferences = getSharedPreferences(PREFS_NAME,Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("username", username.getText().toString());
editor.putString("password", password.getText().toString());
editor.putString("logged", "logged");
editor.commit();

To reset your preferences

重置您的偏好

SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.commit();

回答by alexm

If you are making a large application with other developers in your team and intend to have everything well organized without scattered code or different SharedPreferences instances, you may do something like this:

如果您正在与团队中的其他开发人员一起制作大型应用程序，并打算在没有分散的代码或不同的 SharedPreferences 实例的情况下将所有内容组织得井井有条，您可以这样做：

//SharedPreferences manager class
public class SharedPrefs {

    //SharedPreferences file name
    private static String SHARED_PREFS_FILE_NAME = "my_app_shared_prefs";

    //here you can centralize all your shared prefs keys
    public static String KEY_MY_SHARED_BOOLEAN = "my_shared_boolean";
    public static String KEY_MY_SHARED_FOO = "my_shared_foo";

    //get the SharedPreferences object instance
    //create SharedPreferences file if not present


    private static SharedPreferences getPrefs(Context context) {
        return context.getSharedPreferences(SHARED_PREFS_FILE_NAME, Context.MODE_PRIVATE);
    }

    //Save Booleans
    public static void savePref(Context context, String key, boolean value) {
        getPrefs(context).edit().putBoolean(key, value).commit();       
    }

    //Get Booleans
    public static boolean getBoolean(Context context, String key) {
        return getPrefs(context).getBoolean(key, false);
    }

    //Get Booleans if not found return a predefined default value
    public static boolean getBoolean(Context context, String key, boolean defaultValue) {
        return getPrefs(context).getBoolean(key, defaultValue);
    }

    //Strings
    public static void save(Context context, String key, String value) {
        getPrefs(context).edit().putString(key, value).commit();
    }

    public static String getString(Context context, String key) {
        return getPrefs(context).getString(key, "");
    }

    public static String getString(Context context, String key, String defaultValue) {
        return getPrefs(context).getString(key, defaultValue);
    }

    //Integers
    public static void save(Context context, String key, int value) {
        getPrefs(context).edit().putInt(key, value).commit();
    }

    public static int getInt(Context context, String key) {
        return getPrefs(context).getInt(key, 0);
    }

    public static int getInt(Context context, String key, int defaultValue) {
        return getPrefs(context).getInt(key, defaultValue);
    }

    //Floats
    public static void save(Context context, String key, float value) {
        getPrefs(context).edit().putFloat(key, value).commit();
    }

    public static float getFloat(Context context, String key) {
        return getPrefs(context).getFloat(key, 0);
    }

    public static float getFloat(Context context, String key, float defaultValue) {
        return getPrefs(context).getFloat(key, defaultValue);
    }

    //Longs
    public static void save(Context context, String key, long value) {
        getPrefs(context).edit().putLong(key, value).commit();
    }

    public static long getLong(Context context, String key) {
        return getPrefs(context).getLong(key, 0);
    }

    public static long getLong(Context context, String key, long defaultValue) {
        return getPrefs(context).getLong(key, defaultValue);
    }

    //StringSets
    public static void save(Context context, String key, Set<String> value) {
        getPrefs(context).edit().putStringSet(key, value).commit();
    }

    public static Set<String> getStringSet(Context context, String key) {
        return getPrefs(context).getStringSet(key, null);
    }

    public static Set<String> getStringSet(Context context, String key, Set<String> defaultValue) {
        return getPrefs(context).getStringSet(key, defaultValue);
    }
}

In your activity you may save SharedPreferences this way

在您的活动中，您可以通过这种方式保存 SharedPreferences

//saving a boolean into prefs
SharedPrefs.savePref(this, SharedPrefs.KEY_MY_SHARED_BOOLEAN, booleanVar);

and you may retrieve your SharedPreferences this way

你可以通过这种方式检索你的 SharedPreferences

//getting a boolean from prefs
booleanVar = SharedPrefs.getBoolean(this, SharedPrefs.KEY_MY_SHARED_BOOLEAN);

回答by Sathish

In any application, there are default preferences that can accessed through the PreferenceManagerinstance and its related method getDefaultSharedPreferences(Context).

在任何应用程序中，都有可以通过PreferenceManager实例及其相关方法访问的默认首选项getDefaultSharedPreferences(Context)。

With the SharedPreferenceinstance one can retrieve the int value of the any preference with the getInt(String key, int defVal). The preference we are interested in this case is counter .

对于SharedPreference实例，可以使用getInt(String key, int defVal)检索 any 首选项的 int 值。我们在这种情况下感兴趣的偏好是 counter 。

In our case, we can modify the SharedPreferenceinstance in our case using the edit() and use the putInt(String key, int newVal)We increased the count for our application that presist beyond the application and displayed accordingly.

在我们的案例中，我们可以SharedPreference使用 edit()修改我们案例中的实例，并使用putInt(String key, int newVal)We 增加我们的应用程序的计数，该计数超出应用程序并相应地显示。

To further demo this, restart and you application again, you will notice that the count will increase each time you restart the application.

为了进一步演示这一点，重新启动应用程序，您会注意到每次重新启动应用程序时计数都会增加。

PreferencesDemo.java

首选项演示.java

Code:

代码：

package org.example.preferences;
import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.widget.TextView;

public class PreferencesDemo extends Activity {
   /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Get the app's shared preferences
        SharedPreferences app_preferences = 
        PreferenceManager.getDefaultSharedPreferences(this);

        // Get the value for the run counter
        int counter = app_preferences.getInt("counter", 0);

        // Update the TextView
        TextView text = (TextView) findViewById(R.id.text);
        text.setText("This app has been started " + counter + " times.");

        // Increment the counter
        SharedPreferences.Editor editor = app_preferences.edit();
        editor.putInt("counter", ++counter);
        editor.commit(); // Very important
    }
}

main.xml

主文件

Code:

代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent" >

        <TextView
            android:id="@+id/text"  
            android:layout_width="fill_parent" 
            android:layout_height="wrap_content" 
            android:text="@string/hello" />
</LinearLayout>