使用preferences - 我的列表视图是空的（不能存储数据） [英] using preferences -- my listview is empty (can't store data)

问题描述

我需要为了帮助正确设置preferences。

I need help in order to properly set up preferences.

我有我的主要活动从由pressing菜单按钮，我准备到preferences activity.There，我有3项在用户输入他的data.The第一项是一个序列号

I have my main activity from which by pressing the menu button ,i am going to the preferences activity.There,i have 3 entries where the user inputs his data.The first entry is a serial number.

我希望能够展示所有的序列号列表，当用户选择一个，表明他的其他项目（或做一些计算）。

I want to be able to show a list with all the serial numbers and when the user selects one,show him the other entries (or do some calculations ).

----------已更新------------------------------------

----------UPDATED------------------------------------

我的主要活动是：

 public class Strength extends Activity  implements OnClickListener{


View goto_list;
SharedPreferences mypref;
String [] values=new String [100];

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    //Set up click listeners
    goto_list=(View) findViewById(R.id.goto_list);
    goto_list.setOnClickListener(this);

    //Setup preferences
    mypref= PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor prefsEditr=mypref.edit();

    final Integer counter =values.length; 
    prefsEditr.putInt("size", counter);
    for (int i=0;i<counter;i++) {
        prefsEditr.putString("serial_number"+i, values[i]);
    }

    prefsEditr.putString("date", "");
    prefsEditr.putString("strength", "1.0");
    prefsEditr.commit();     

}

我goto_list活动，这将显示带有序列号列表视图：

My goto_list activity which will show the listview with the serial numbers:

   public class goto_list extends ListActivity {
private final String TAG="list";
SharedPreferences mypref;
    String[] listItems = null;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.list);


    mypref= PreferenceManager.getDefaultSharedPreferences(this);

    final Integer counter = mypref.getInt("size",0); 
    listItems=new String[counter];
    for (int i=0;i<counter;i++) {
        listItems[i] = mypref.getString("serial_number"+i, "");
    }

   //what to do with ArrayAdapter? 
   ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1,listItems);              
   setListAdapter(adapter);
}
       protected void onListItemClick(ListView l, View v, int position, long id) {
    Log.i(TAG, "position: " + position);
        Log.i(TAG, "item: " + listItems[position]);
        mypref.edit().putString("serial_number", listItems[position]).commit();

    String item = (String) getListAdapter().getItem(position);
    Intent i=new Intent(this,calcs_strength.class);
    startActivity(i);
    finish();

}

所以，我的问题是，列表视图是empty.It不显示数据。

So, my problem is that the listview is empty.It show no data.

感谢您！

推荐答案

您的数组是空的。

更改此：

for (int i=0;i<counter;i++) {
    prefsEditr.putString("serial_number"+i, values[i]);
}

与

for (int i=0;i<counter;i++) {
    // just replace the string with you serial number;
    values[i] = "998-123-234-122_" + i;
    prefsEditr.putString("serial_number"+i, values[i]);
}

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