我一直在尝试使用一个 android 偏好活动,我已经完成了所有设置,但我在实际检索用户偏好时遇到了麻烦。具体来说,我想检索两个edittext首选项,即期限长度和年份长度,以便检索int的值,以便我可以在另一个活动的计算中使用它们。
我找到的每个例子都是不同的,我真的找不到明确的解释。我将在下面发布我正在使用的类和方法,我知道那里的代码不正确,但我觉得我现在已经把它弄乱了,无法弄清楚。特别是这条线我不认为是正确的:SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
而且我并不真正理解整个偏好活动,它们似乎没有像我预期的那样工作。任何建议都会很棒!几天来,我一直在处理相同的代码行。
谢谢。
我的偏好活动如下所示:
package com.geistware.studentbudgetapp;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
import android.text.method.DigitsKeyListener;
import android.util.Log;
public class UserPrefs extends PreferenceActivity {
public int termLength = 1;
public int yearLength = 1;
@Override //OnCreate never runs, why?
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.setup);
EditTextPreference usersTermLength =(EditTextPreference)
findPreference(getString(R.string.term_length_set)); //finds
//the edittext box by its key, term_length_set
usersTermLength.getEditText().setKeyListener(DigitsKeyListener.
getInstance()); //DigitsKeyListener only allows digits to be typed in
Log.v("UserPrefs", "UsersTermLength: " + usersTermLength);
EditTextPreference usersYearLength =(EditTextPreference)
findPreference(getString(R.string.year_length_set));
usersYearLength.getEditText().setKeyListener(DigitsKeyListener.
getInstance());
}
}
我希望能够在此方法中检索用户 termLength 和 yearLength (作为整数):
public float alterForFrequency(float enteredAmount, String spinnerPosition){
//get user preferences (not working)
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String termKey = getString(R.string.term_length_set, "");
String yearKey = getString(R.string.year_length_set, "");
int termLength = prefs.getInt(termKey, 1);
int yearLength = prefs.getInt(yearKey, 1);
Log.v("alterForFrequency", "userprefs: " + termLength + yearLength);
//perform calculations for monthly/temly/yearly
if(spinnerPosition.equals("Monthly")){
usersAmount = ((enteredAmount / 31)* 7);
Log.v("FiscFreq", "revisingAmount=" + usersAmount);
}
else if(spinnerPosition.equals("Termly")){
usersAmount = (enteredAmount / termLength);
Log.v("FiscFreq", "revisingAmount=" + usersAmount);
}
else if(spinnerPosition.equals("Yearly")){
usersAmount = (enteredAmount / yearLength);
}
else{
usersAmount = enteredAmount;
}
currencyRevisedAmount = toCurrency(usersAmount); //drops the unwanted digits
return currencyRevisedAmount;
}
我实际上是在创建一个 FiscalFrequency 的实例,以便在一个名为 Keypad 的活动中使用 alterForFrequency,如下所示:
public class Keypad extends Activity { .....
public float reviseOnSpinnerPos(){
enteredAmount = Float.valueOf(userAmount.getText().toString());
FiscalFrequency ff = new FiscalFrequency();
revisedAmount = ff.alterForFrequency(enteredAmount, spinnerPosition);
return revisedAmount;
}
}