java - 共享首选项未更新

Question

我正试图让世界创造者像在游戏中一样，我正在使用共享首选项来存储数组等。但有一个问题。我试图从另一个类更新它，所以我使用静态变量来这样做。但是当我用 ListView 回到原来的类时，我发现什么都没有更新。有任何想法吗？这是代码。哦，logcat 中没有错误。

ListView 类。

package you.don't.need-to-know;

import android.app.ListActivity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class WorldMenu extends  ListActivity{
public static SharedPreferences prefs = null;
static String splitter;
String[] worldList;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    prefs = PreferenceManager.getDefaultSharedPreferences(this);
    splitter =  "Create World," + prefs.getString("worldString", "");
    worldList = splitter.split(",");
    setListAdapter(new ArrayAdapter<String>(WorldMenu.this,
    android.R.layout.simple_list_item_1, worldList));


}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    // TODO Auto-generated method stub
    super.onListItemClick(l, v, position, id);
    if(position == 0){
        Intent openWorldNamer = new                                           
 Intent("you.don't.need-to-know");
        startActivity(openWorldNamer);
    }

}


}

更新器:

package you.don't.need-to-know;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class WorldCreator extends Activity{
EditText worldNameEditor;
Button saver;
static String updater;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_worldcreator);
    worldNameEditor = (EditText) findViewById(R.id.editText1);
    saver = (Button) findViewById(R.id.button1);
    updater = worldNameEditor.getText().toString() + ",";
    saver.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Editor editor = WorldMenu.prefs.edit();
            editor.putString("worldString", updater);
            editor.commit();
            Intent openListWorld = new
 Intent("you.don't.need.to-know");
            startActivity(openListWorld);
        }
    });
}
@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();

}

}

编辑:新代码已更新，接近修复。更新程序和列表 Activity

更新者:

 import android.app.Activity;

 import android.content.Intent;

 import android.content.SharedPreferences;

 import android.content.SharedPreferences.Editor;

 import android.content.SharedPreferences.OnSharedPreferenceChangeListener;

 import android.os.Bundle;

 import android.preference.PreferenceManager;

 import android.view.View;

 import android.widget.Button;

 import android.widget.EditText;


public class WorldCreator extends Activity{
EditText worldNameEditor;
Button saver;
SharedPreferences prefs;
OnSharedPreferenceChangeListener listener;
String updater;
Editor editor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_worldcreator);
    prefs = PreferenceManager.getDefaultSharedPreferences(this);
    worldNameEditor = (EditText) findViewById(R.id.hello);
    saver = (Button) findViewById(R.id.button1);
    updater = worldNameEditor.getText().toString() + ",";

saver.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        listener = new SharedPreferences.OnSharedPreferenceChangeListener()  
{
            public void onSharedPreferenceChanged(SharedPreferences      
  prefs, String key) {
                editor = prefs.edit();
                editor.putString("worldString", updater);   
                editor.commit();
              }
            };

            prefs.registerOnSharedPreferenceChangeListener(listener);
            Intent openListWorld = new                                    
 Intent("");
            startActivity(openListWorld);

    }});

    }
    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();





    }





@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();

}
}

列表 Activity :

import android.app.ListActivity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class WorldMenu extends  ListActivity{
SharedPreferences prefs = null;
String splitter;
String[] worldList;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    prefs = PreferenceManager.getDefaultSharedPreferences(this);
    splitter =  "Create World," + prefs.getString("worldString", "hello");
    worldList = splitter.split(",");
    setListAdapter(new ArrayAdapter<String>(WorldMenu.this,          
 android.R.layout.simple_list_item_1, worldList));
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    // TODO Auto-generated method stub
    super.onListItemClick(l, v, position, id);
    if(position == 0){
        Intent openWorldNamer = new                                          
Intent("");
        startActivity(openWorldNamer);
    }

}

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    finish();
}


}

Answer 1

您似乎没有在监视共享首选项的更改。见:

http://developer.android.com/reference/android/content/SharedPreferences.OnSharedPreferenceChangeListener.html

final SharedPreferences.OnSharedPreferenceChangeListener listener = new SharedPreferences.OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
    // update your listview.
  }
};

prefs.registerOnSharedPreferenceChangeListener(listener);

因此，当您收到该回调时，它会告诉您更改了哪个键。然后您可以更新 ListView 的适配器以包含新内容并在适配器中调用 onDataSetChanged()。

或者，您可以将适配器设置代码移动到 onResume() 函数中。这样当您的 Activity 恢复时，您就可以检查共享首选项的状态并设置适配器。但是请注意，如果用户向下滚动列表一段距离并且您在恢复中再次调用 setAdapter()，他们将失去滚动位置。

编辑:

尝试:

Updater(这不应该需要开始一个新的 Activity ，这可以直接完成()):

import android.app.Activity;

 import android.content.Intent;

 import android.content.SharedPreferences;

 import android.content.SharedPreferences.Editor;

 import android.content.SharedPreferences.OnSharedPreferenceChangeListener;

 import android.os.Bundle;

 import android.preference.PreferenceManager;

 import android.view.View;

 import android.widget.Button;

 import android.widget.EditText;


public class WorldCreator extends Activity{
EditText worldNameEditor;
Button saver;
SharedPreferences prefs;
OnSharedPreferenceChangeListener listener;
String updater;
Editor editor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_worldcreator);
    prefs = PreferenceManager.getDefaultSharedPreferences(this);
    worldNameEditor = (EditText) findViewById(R.id.hello);
    saver = (Button) findViewById(R.id.button1);
    updater = worldNameEditor.getText().toString() + ",";

saver.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
           editor = prefs.edit();
           editor.putString("worldString", updater);   
           editor.commit();
           finish();
    }});

    }

ListView :

import android.app.ListActivity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class WorldMenu extends  ListActivity{
SharedPreferences prefs = null;
String splitter;
String[] worldList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    prefs = PreferenceManager.getDefaultSharedPreferences(this);
final SharedPreferences.OnSharedPreferenceChangeListener listener = new SharedPreferences.OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
    // update your listview.
  }
};

prefs.registerOnSharedPreferenceChangeListener(listener);

}

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();

    splitter =  "Create World," + prefs.getString("worldString", "hello");
    worldList = splitter.split(",");
    setListAdapter(new ArrayAdapter<String>(WorldMenu.this,          
 android.R.layout.simple_list_item_1, worldList));
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    // TODO Auto-generated method stub
    super.onListItemClick(l, v, position, id);
    if(position == 0){
        Intent openWorldNamer = new                                          
Intent("");
        startActivity(openWorldNamer);
    }

}
}