Android - SharedPreference转换为Double [英] Android - SharedPreference converting to Double

问题描述

我正在检索保存的值，并尝试在计算中使用它。

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如何将其转换为双倍而不是字符串？

一旦值为在计算后检索，新值将保存回相同值的共享引用。

希望你能理解，一直遇到麻烦！

  SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences（getApplicationContext（））; 
 String newweight = sharedPreferences.getString（storednewweight，）; 
 newweight = newweight + 5; 
 //将值保存到sharedpreference 
 savePreferences（storednewweight，（Double.toString（newweight）））; 
  

解决方案

您可以将字符串解析为双精度：

  SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences（getApplicationContext（））; 
 
 String weight = sharedPreferences.getString（storednewweight，）; 
 Double newweight = Double.parseDouble（weight）; 
 newweight = newweight + 5; 
 
 //将值保存到sharedpreference 
 savePreferences（storednewweight，（Double.toString（newweight）））; 
  

Basically i have a valued saved into shared preference as a string.

I am retrieving the value saved, and am trying to use it in a calculation.

How can i convert this so that it is seen as a double instead of a string?

Once the value is retrieved after the calculation, the new value is saved back into the sharedpreference under the same value.

I hope you can understand, been having trouble with this!

            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
            String newweight =  sharedPreferences.getString("storednewweight", "");
            newweight = newweight + 5;
            //saves value into sharedpreference
            savePreferences("storednewweight", (Double.toString(newweight)));

解决方案

You can parse the string as a double:

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

String weight =  sharedPreferences.getString("storednewweight", "");
Double newweight = Double.parseDouble(weight);
newweight = newweight + 5;

//saves value into sharedpreference
savePreferences("storednewweight", (Double.toString(newweight)));

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