Question

我正在尝试使用共享首选项将值从一个活动传递到另一个活动，但是我获得了null值。在第一个活动中，我在控制台中打印了值并将其打印但是我无法检索这些值。请帮我解决这个错误

第一项活动：传递值

sharedpreferences.edit().putString("CHECKPASS","changepass").commit();
editor.putString("FOOD",food1);
editor.putString("PLACE",place1);
editor.putString("COLOR",colour1);
editor.putString("BUY",buy1);
editor.commit();

第二项活动：我正在检索的地方

     Log.d("succ", "reached");
        String yourpass = sharedpreferences.getString("CHECKPASS","changepass");
        Log.d("succ", "yournext" + yourpass);

        if (yourpass.equals("changepass")) {
            {
                final String foodshared = sharedpreferences.getString("FOOD","NULL");
                Log.d("succ", "foodshared" + foodshared);

                final String colorshared = sharedpreferences.getString("COLOR", "NULL");
                Log.d("succ", "colorshared" + colorshared);

                final String buyshared = sharedpreferences.getString("BUY", "NULL");
                Log.d("succ", "buyshared" + buyshared);

                final String placeshared = sharedpreferences.getString("PLACE", "NULL");
                Log.d("succ", "placeshared" + placeshared);



}

Answer 1

使用此代码

//用于写入数据

SharedPreferences.Editor 
editor=getSharedPreferences("nameOFSharedPref",MODE_PRIVATE).edit();
editor.putString("CHECKPASS","changepass");
editor.putString("FOOD",food1);
editor.putString("PLACE",place1);
editor.putString("COLOR",colour1);
editor.putString("BUY",buy1);
editor.apply();

//读取数据

SharedPreferences sharedPreferences=getSharedPreferences("nameOFSharedPref",MODE_PRIVATE);
String foodshared = sharedPreferences.getString("FOOD","NULL");
String colorshared = sharedPreferences.getString("COLOR", "NULL");
final String buyshared = sharedPreferences.getString("BUY", "NULL");
final String placeshared = sharedPreferences.getString("PLACE", "NULL");

同样在编写数据时不要使用editor.commit（）而是使用editor.apply（），因为它在后台处理数据。

Answer 2

更新：

在您的第一个活动中

SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0);//or MODE_PRIVATE
Editor editor = pref.edit();
editor.putString("CHECKPASS","changepass")
editor.putString("FOOD",food1);
editor.putString("PLACE",place1);
editor.putString("COLOR",colour1);
editor.putString("BUY",buy1);
editor.commit();

在你的secondActivity中

 SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0);

 final String foodshared = pref.getString("FOOD",null);
            Log.d("succ", "foodshared" + foodshared);

            final String colorshared = pref.getString("COLOR",null);
            Log.d("succ", "colorshared" + colorshared);

            final String buyshared = pref.getString("BUY",null);
            Log.d("succ", "buyshared" + buyshared);

            final String placeshared = pref.getString("PLACE",null);
            Log.d("succ", "placeshared" + placeshared);

修改：

初始化

SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0); Editor editor = pref.edit();

存储数据

editor.putBoolean("key_name", true); // Storing boolean - true/false editor.putString("key_name", "string value"); // Storing string editor.commit(); // commit changes

检索数据

pref.getString("key_name", null); // getting String pref.getBoolean("key_name", null); // getting boolean

我正在尝试将共享首选项中的值从一个Activity传递到另一个Activity

2 个答案: