我正在Android中编写代码以保存日期选择器中的所选日期。我在Sharedpreference对象中保存日期，但在关闭和打开应用程序后显示最新结果。
我认为必须有刷新活动需要显示来自SharedPreference对象的最新保存结果，所以我使用了AsyncTask并试图获得最新结果但是应用程序没有显示最新结果，每当我关闭应用程序并重新 - 再次打开应用程序，然后我可以看到最新保存的结果。
我的代码：
package com.example.date_pick;
import java.util.Calendar;
import java.util.concurrent.ExecutionException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.app.Dialog;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity{
DatePicker pickerDate;
TextView info;
Button btn;
Button btn12;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button)findViewById(R.id.btn);
info = (TextView)findViewById(R.id.test);
final SharedPreferences pref = getApplicationContext().getSharedPreferences("Demo", 0);
btn.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
final Dialog dia = new Dialog(MainActivity.this);
dia.requestWindowFeature(dia.getWindow().FEATURE_NO_TITLE);
dia.setContentView(R.layout.mydate);
btn12 = (Button)dia.findViewById(R.id.btn1);
pickerDate = (DatePicker)dia.findViewById(R.id.pickerdate);
Calendar today = Calendar.getInstance();
pickerDate.init(
today.get(Calendar.YEAR),
today.get(Calendar.MONTH),
today.get(Calendar.DAY_OF_MONTH),
new OnDateChangedListener(){
@Override
public void onDateChanged(DatePicker view, int year, int monthOfYear,int dayOfMonth)
{
Toast.makeText(getApplicationContext(), "onDateChanged", Toast.LENGTH_SHORT).show();
Editor et = pref.edit();
et.remove("year");
et.remove("month");
et.remove("day");
et.commit();
et.putInt("year", year);
et.putInt("month", monthOfYear);
et.putInt("day", dayOfMonth);
et.commit();
}});
btn12.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dia.dismiss();
}
});
dia.show();
}
});
MyShared ms = new MyShared();
String save_date;
try {
save_date = ms.execute().get();
info.setText("Result : "+save_date);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private class MyShared extends AsyncTask<String ,Void, String>
{
String save_date = null;
SharedPreferences pref = getApplicationContext().getSharedPreferences("Demo", 0);
@Override
protected String doInBackground(String... params)
{
int year = pref.getInt("year", 0);
int month = pref.getInt("month", 0);
int day = pref.getInt("day", 0);
String data = String.valueOf(day+"/"+month+"/"+year);
return data;
}
}
}
如何从SharedPreference对象获取最新保存的结果。请告诉我，建议我一些好的解决方案。
答案 0 :(得分：1)
查看你的代码，你初始化onDateChanged然后执行asynctask。
你得到第一个结果。
然后onDateChanged更改首选项，您需要再次调用它。
代码（未经测试）
import java.util.Calendar;
import java.util.concurrent.ExecutionException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.app.Dialog;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity{
DatePicker pickerDate;
TextView info;
Button btn;
Button btn12;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button)findViewById(R.id.btn);
info = (TextView)findViewById(R.id.test);
final SharedPreferences pref = getApplicationContext().getSharedPreferences("Demo", 0);
new MyShared().execute();
btn.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
final Dialog dia = new Dialog(MainActivity.this);
dia.requestWindowFeature(dia.getWindow().FEATURE_NO_TITLE);
dia.setContentView(R.layout.mydate);
btn12 = (Button)dia.findViewById(R.id.btn1);
pickerDate = (DatePicker)dia.findViewById(R.id.pickerdate);
Calendar today = Calendar.getInstance();
pickerDate.init(
today.get(Calendar.YEAR),
today.get(Calendar.MONTH),
today.get(Calendar.DAY_OF_MONTH),
new OnDateChangedListener(){
@Override
public void onDateChanged(DatePicker view, int year, int monthOfYear,int dayOfMonth)
{
Toast.makeText(getApplicationContext(), "onDateChanged", Toast.LENGTH_SHORT).show();
Editor et = pref.edit();
et.remove("year");
et.remove("month");
et.remove("day");
et.commit();
et.putInt("year", year);
et.putInt("month", monthOfYear);
et.putInt("day", dayOfMonth);
et.commit();
new MyShared().execute();
}});
btn12.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dia.dismiss();
}
});
dia.show();
}
});
}
private class MyShared extends AsyncTask<String ,Void, String>
{
SharedPreferences pref = getApplicationContext().getSharedPreferences("Demo", 0);
@Override
protected String doInBackground(String... params)
{
int year = pref.getInt("year", 0);
int month = pref.getInt("month", 0);
int day = pref.getInt("day", 0);
String data = String.valueOf(day+"/"+month+"/"+year);
return data;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
info.setText(s);
}
}
}
答案 1 :(得分：0)
dia.dismiss();执行你的asynctask之后。即，在您关闭DatePicker后，将所有代码从MyShared ms = new MyShared()...写到catch(ExecuteException e){}...。
这将关闭对话框并从sharedPreferences读取数据并更新信息。