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

在这里,我创建了一个Helper类来使用android中的首选项。

这是helper类:

public class PrefsUtil {

public static SharedPreferences getPreference() {
    return PreferenceManager.getDefaultSharedPreferences(Applicatoin.getAppContext());
}

public static void putBoolean(String key, boolean value) {
    getPreference().edit().putBoolean(key, value)
            .apply();
}

public static boolean getBoolean(String key) {
    return getPreference().getBoolean(key, false);
}

public static void putInt(String key, int value) {

    getPreference().edit().putInt(key, value).apply();

}

public static void delKey(String key) {

    getPreference().edit().remove(key).apply();

}

}

其他回答

简单和无麻烦::"Android-SharedPreferences-Helper"库

迟到总比不到好:我创建了“Android-SharedPreferences-Helper”库来帮助降低使用SharedPreferences的复杂性和工作量。它还提供了一些扩展功能。它提供的一些东西如下:

一行初始化和设置 轻松选择是使用默认首选项还是自定义首选项文件 每种数据类型的预定义(默认数据类型)和自定义(您可以选择的)默认值 能力设置不同的默认值为单一使用,只是一个额外的参数 你可以注册和取消注册OnSharedPreferenceChangeListener,因为你做的默认类

dependencies {
    ...
    ...
    compile(group: 'com.viralypatel.sharedpreferenceshelper', name: 'library', version: '1.1.0', ext: 'aar')
}

SharedPreferencesHelper对象的声明:(建议在类中 级)

SharedPreferencesHelper sph; 

SharedPreferencesHelper对象的实例化:(建议在 onCreate()方法)

// use one of the following ways to instantiate
sph = new SharedPreferencesHelper(this); //this will use default shared preferences
sph = new SharedPreferencesHelper(this, "myappprefs"); // this will create a named shared preference file
sph = new SharedPreferencesHelper(this, "myappprefs", 0); // this will allow you to specify a mode

将价值观融入到共同的偏好中

非常简单!不像默认的方式(当使用SharedPreferences类时),你不需要调用.edit()和.commit()。

sph.putBoolean("boolKey", true);
sph.putInt("intKey", 123);
sph.putString("stringKey", "string value");
sph.putLong("longKey", 456876451);
sph.putFloat("floatKey", 1.51f);

// putStringSet is supported only for android versions above HONEYCOMB
Set name = new HashSet();
name.add("Viral");
name.add("Patel");
sph.putStringSet("name", name);

就是这样!您的值存储在共享首选项中。

从共享首选项中获取值

同样,这只是一个使用键名的简单方法调用。

sph.getBoolean("boolKey");
sph.getInt("intKey");
sph.getString("stringKey");
sph.getLong("longKey");
sph.getFloat("floatKey");

// getStringSet is supported only for android versions above HONEYCOMB
sph.getStringSet("name");

它还有很多其他扩展功能

在GitHub知识库页面上查看扩展功能的详细信息,使用和安装说明等。

我创建了一个Helper类来简化我的生活。这是一个泛型类,有很多在应用程序中常用的方法,如共享首选项,电子邮件有效性,日期时间格式。在代码中复制这个类,并在任何需要的地方访问它的方法。

 import android.app.AlertDialog;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.SharedPreferences;
 import android.support.v4.app.FragmentActivity;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.EditText;
 import android.widget.Toast;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Random;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;

/**
* Created by Zohaib Hassan on 3/4/2016.
*/
 public class Helper {

private static ProgressDialog pd;

public static void saveData(String key, String value, Context context) {
    SharedPreferences sp = context.getApplicationContext()
            .getSharedPreferences("appData", 0);
    SharedPreferences.Editor editor;
    editor = sp.edit();
    editor.putString(key, value);
    editor.commit();
}

public static void deleteData(String key, Context context){
    SharedPreferences sp = context.getApplicationContext()
            .getSharedPreferences("appData", 0);
    SharedPreferences.Editor editor;
    editor = sp.edit();
    editor.remove(key);
    editor.commit();

}

public static String getSaveData(String key, Context context) {
    SharedPreferences sp = context.getApplicationContext()
            .getSharedPreferences("appData", 0);
    String data = sp.getString(key, "");
    return data;

}




public static long dateToUnix(String dt, String format) {
    SimpleDateFormat formatter;
    Date date = null;
    long unixtime;
    formatter = new SimpleDateFormat(format);
    try {
        date = formatter.parse(dt);
    } catch (Exception ex) {

        ex.printStackTrace();
    }
    unixtime = date.getTime();
    return unixtime;

}

public static String getData(long unixTime, String formate) {

    long unixSeconds = unixTime;
    Date date = new Date(unixSeconds);
    SimpleDateFormat sdf = new SimpleDateFormat(formate);
    String formattedDate = sdf.format(date);
    return formattedDate;
}

public static String getFormattedDate(String date, String currentFormat,
                                      String desiredFormat) {
    return getData(dateToUnix(date, currentFormat), desiredFormat);
}




public static double distance(double lat1, double lon1, double lat2,
                              double lon2, char unit) {
    double theta = lon1 - lon2;
    double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2))
            + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2))
            * Math.cos(deg2rad(theta));
    dist = Math.acos(dist);
    dist = rad2deg(dist);
    dist = dist * 60 * 1.1515;
    if (unit == 'K') {
        dist = dist * 1.609344;
    } else if (unit == 'N') {
        dist = dist * 0.8684;
    }
    return (dist);
}

/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
/* :: This function converts decimal degrees to radians : */
/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
private static double deg2rad(double deg) {
    return (deg * Math.PI / 180.0);
}

/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
/* :: This function converts radians to decimal degrees : */
/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */
private static double rad2deg(double rad) {
    return (rad * 180.0 / Math.PI);
}

public static int getRendNumber() {
    Random r = new Random();
    return r.nextInt(360);
}

public static void hideKeyboard(Context context, EditText editText) {
    InputMethodManager imm = (InputMethodManager) context
            .getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(editText.getWindowToken(), 0);
}

public static void showLoder(Context context, String message) {
    pd = new ProgressDialog(context);

    pd.setCancelable(false);
    pd.setMessage(message);
    pd.show();
}

public static void showLoderImage(Context context, String message) {
    pd = new ProgressDialog(context);
    pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    pd.setCancelable(false);
    pd.setMessage(message);
    pd.show();
}

public static void dismissLoder() {
    pd.dismiss();
}

public static void toast(Context context, String text) {

    Toast.makeText(context, text, Toast.LENGTH_LONG).show();
}
/*
     public static Boolean connection(Context context) {
    ConnectionDetector connection = new ConnectionDetector(context);
    if (!connection.isConnectingToInternet()) {

        Helper.showAlert(context, "No Internet access...!");
        //Helper.toast(context, "No internet access..!");
        return false;
    } else
        return true;
}*/

public static void removeMapFrgment(FragmentActivity fa, int id) {

    android.support.v4.app.Fragment fragment;
    android.support.v4.app.FragmentManager fm;
    android.support.v4.app.FragmentTransaction ft;
    fm = fa.getSupportFragmentManager();
    fragment = fm.findFragmentById(id);
    ft = fa.getSupportFragmentManager().beginTransaction();
    ft.remove(fragment);
    ft.commit();

}

public static AlertDialog showDialog(Context context, String message) {
    AlertDialog.Builder builder = new AlertDialog.Builder(context);
    builder.setMessage(message);

    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int id) {
            // TODO Auto-generated method stub

        }
    });

    return builder.create();
}

public static void showAlert(Context context, String message) {
    AlertDialog.Builder builder = new AlertDialog.Builder(context);
    builder.setTitle("Alert");
    builder.setMessage(message)
            .setPositiveButton("Ok", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.dismiss();
                }
            }).show();
}

public static boolean isURL(String url) {
    if (url == null)
        return false;

    boolean foundMatch = false;
    try {
        Pattern regex = Pattern
                .compile(
                        "\\b(?:(https?|ftp|file)://|www\\.)?[-A-Z0-9+&#/%?=~_|$!:,.;]*[A-Z0-9+&@#/%=~_|$]\\.[-A-Z0-9+&@#/%?=~_|$!:,.;]*[A-Z0-9+&@#/%=~_|$]",
                        Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
        Matcher regexMatcher = regex.matcher(url);
        foundMatch = regexMatcher.matches();
        return foundMatch;
    } catch (PatternSyntaxException ex) {
        // Syntax error in the regular expression
        return false;
    }
}

public static boolean atLeastOneChr(String string) {
    if (string == null)
        return false;

    boolean foundMatch = false;
    try {
        Pattern regex = Pattern.compile("[a-zA-Z0-9]",
                Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
        Matcher regexMatcher = regex.matcher(string);
        foundMatch = regexMatcher.matches();
        return foundMatch;
    } catch (PatternSyntaxException ex) {
        // Syntax error in the regular expression
        return false;
    }
}

public static boolean isValidEmail(String email, Context context) {
    String expression = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
    CharSequence inputStr = email;
    Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(inputStr);
    if (matcher.matches()) {
        return true;
    } else {
        // Helper.toast(context, "Email is not valid..!");

        return false;
    }
}

public static boolean isValidUserName(String email, Context context) {
    String expression = "^[0-9a-zA-Z]+$";
    CharSequence inputStr = email;
    Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
    Matcher matcher = pattern.matcher(inputStr);
    if (matcher.matches()) {
        return true;
    } else {
        Helper.toast(context, "Username is not valid..!");
        return false;
    }
}

public static boolean isValidDateSlash(String inDate) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd/mm/yyyy");
    dateFormat.setLenient(false);
    try {
        dateFormat.parse(inDate.trim());
    } catch (ParseException pe) {
        return false;
    }
    return true;
}

public static boolean isValidDateDash(String inDate) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd-mm-yyyy");
    dateFormat.setLenient(false);
    try {
        dateFormat.parse(inDate.trim());
    } catch (ParseException pe) {
        return false;
    }
    return true;
}

public static boolean isValidDateDot(String inDate) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd.mm.yyyy");
    dateFormat.setLenient(false);
    try {
        dateFormat.parse(inDate.trim());
    } catch (ParseException pe) {
        return false;
    }
    return true;
}

}

使用这个简单的库,下面是如何调用SharedPreferences..

TinyDB tinydb = new TinyDB(context);

tinydb.putInt("clickCount", 2);

tinydb.putString("userName", "john");
tinydb.putBoolean("isUserMale", true); 

tinydb.putList("MyUsers", mUsersArray);
tinydb.putImagePNG("DropBox/WorkImages", "MeAtlunch.png", lunchBitmap);

//These plus the corresponding get methods are all Included

要获得共享首选项,请使用以下方法 在活动中:

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

读取首选项:

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

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

编辑和保存首选项

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

android sdk的示例目录包含一个检索和存储共享首选项的示例。它位于:

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

编辑= = >

我注意到,在这里写commit()和apply()之间的区别也很重要。

如果保存成功,Commit()返回true,否则返回false。它同步保存值到SharedPreferences。

Apply()是在2.3中添加的,无论成功还是失败都不返回任何值。它会立即将值保存到SharedPreferences,但会启动异步提交。 更多细节在这里。

我为sharedpreferences写了一个helper类:

import android.content.Context;
import android.content.SharedPreferences;

/**
 * Created by mete_ on 23.12.2016.
 */
public class HelperSharedPref {

Context mContext;

public HelperSharedPref(Context mContext) {
    this.mContext = mContext;
}

/**
 *
 * @param key Constant RC
 * @param value Only String, Integer, Long, Float, Boolean types
 */
public void saveToSharedPref(String key, Object value) throws Exception {
    SharedPreferences.Editor editor = mContext.getSharedPreferences(key, Context.MODE_PRIVATE).edit();
    if (value instanceof String) {
        editor.putString(key, (String) value);
    } else if (value instanceof Integer) {
        editor.putInt(key, (Integer) value);
    } else if (value instanceof Long) {
        editor.putLong(key, (Long) value);
    } else if (value instanceof Float) {
        editor.putFloat(key, (Float) value);
    } else if (value instanceof Boolean) {
        editor.putBoolean(key, (Boolean) value);
    } else {
        throw new Exception("Unacceptable object type");
    }

    editor.commit();
}

/**
 * Return String
 * @param key
 * @return null default is null
 */
public String loadStringFromSharedPref(String key) throws Exception {
    SharedPreferences prefs = mContext.getSharedPreferences(key, Context.MODE_PRIVATE);
    String restoredText = prefs.getString(key, null);

    return restoredText;
}

/**
 * Return int
 * @param key
 * @return null default is -1
 */
public Integer loadIntegerFromSharedPref(String key) throws Exception {
    SharedPreferences prefs = mContext.getSharedPreferences(key, Context.MODE_PRIVATE);
    Integer restoredText = prefs.getInt(key, -1);

    return restoredText;
}

/**
 * Return float
 * @param key
 * @return null default is -1
 */
public Float loadFloatFromSharedPref(String key) throws Exception {
    SharedPreferences prefs = mContext.getSharedPreferences(key, Context.MODE_PRIVATE);
    Float restoredText = prefs.getFloat(key, -1);

    return restoredText;
}

/**
 * Return long
 * @param key
 * @return null default is -1
 */
public Long loadLongFromSharedPref(String key) throws Exception {
    SharedPreferences prefs = mContext.getSharedPreferences(key, Context.MODE_PRIVATE);
    Long restoredText = prefs.getLong(key, -1);

    return restoredText;
}

/**
 * Return boolean
 * @param key
 * @return null default is false
 */
public Boolean loadBooleanFromSharedPref(String key) throws Exception {
    SharedPreferences prefs = mContext.getSharedPreferences(key, Context.MODE_PRIVATE);
    Boolean restoredText = prefs.getBoolean(key, false);

    return restoredText;
}

}