如何检查SharedPreferences中是否存在数据

How we can check whether the data exists in the SharedPreferences.if exists then start new activity?

我们如何检查SharedPreferences.if中是否存在数据，然后启动新活动？

4 个解决方案

#1

SharedPreferences prefs = getSharedPreferences("application_settings", 0);
int id = prefs.getInt("id", 0);
if(id > 0) {
  startActivity(new Intent(CurrentCLass.this, NextClass.class));
}

#2

Whenever you retrieve the data, you always need to supply a default parameter to return if the data doesn't exist, so for example

每当您检索数据时，如果数据不存在，您总是需要提供一个默认参数来返回，例如

SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(getContext());
int data = pref.getInt("key",-1);

then data will be -1 if the preference value for "key" doesn't exist.

如果“key”的首选项值不存在，则数据将为-1。

#3

if (preferences.contains("yourKey")){
    startActivity(new Intent(CurrentActivity.this, NewActivity.class));
}

#4

A simple Solution. Get Data From Shared Preference. If Data Not Found Then It Returns null So Check if String Variable get null or any other Value.

简单的解决方案。从共享首选项中获取数据。如果找不到数据则返回null所以检查字符串变量是否为null或任何其他值。

File f = new File("/data/data/" + getPackageName() +  "/shared_prefs/mypref.xml");
        if(f.exists())
        { 

            String user=mypref.getString("UserName", null);
            if(user!=null){     
                                   //do stuff`enter code here
            }
        }

#1

SharedPreferences prefs = getSharedPreferences("application_settings", 0);
int id = prefs.getInt("id", 0);
if(id > 0) {
  startActivity(new Intent(CurrentCLass.this, NextClass.class));
}

#2