android - How to Check data exists in SharedPreferences

Question

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

Answer 1

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

Answer 2

每当您检索数据时，您总是需要提供一个默认参数以在数据不存在时返回，例如

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

如果“key”的首选项值不存在，那么data将是。-1

Answer 3

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

Answer 4

一个简单的解决方案。从共享偏好中获取数据。如果未找到数据，则返回null因此检查字符串变量是否为空或任何其他值。

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
            }
        }