java - Android 中使用 SharedPreferences 的动态列表

Question

我正在开发一个需要创建动态列表的项目。为此，我使用共享首选项将值永久存储在列表中。但是当我重新启动项目时，我会使用该值输入不退出。我尝试了很多次，但问题没有解决。
这是我的代码。
NumberListActivity.java

public class NumberListActivity extends Activity {
    ListView numList;
    ArrayList<String> list = new ArrayList<String>();
    ArrayAdapter<String> adapter;
    public static final String Place = "placeKey";
    Button btnAdd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.custom_list);
        numList = (ListView) findViewById(R.id.list);
        btnAdd = (Button) findViewById(R.id.btnAdd);
        adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, list);
        numList.setAdapter(adapter);
        btnAdd.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                SharedPreferences preferences = getSharedPreferences("place",
                        Context.MODE_PRIVATE);
                SharedPreferences.Editor spEditor = preferences.edit();
                EditText edit = (EditText) findViewById(R.id.txtItem);
                spEditor.putString("Value", edit.getText().toString());
                spEditor.commit();
                list.add(preferences.getString("Value", ""));
                adapter.notifyDataSetChanged();

            }
        });
        list.toArray();

    }

}      

自定义列表.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/txtItem"
        android:layout_width="240dp"
        android:layout_height="wrap_content"
        android:inputType="text" />

    <Button
        android:id="@+id/btnAdd"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/txtItem" />

    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/txtItem" />

    <TextView
        android:id="@+id/empty"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/txtItem"
        android:gravity="center_horizontal" />

</RelativeLayout>

Answer 1

试试这个..

SharedPreferences preferences;
SharedPreferences.Editor spEditor;
int count = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.custom_list);

    preferences = getSharedPreferences("place", Context.MODE_PRIVATE);
    spEditor = preferences.edit();
    count = preferences.getInt("count", 0);
    if(count > 0){
       for(int i = 0; i < count; i++){
            list.add(preferences.getString("Value["+i+"]", ""));
       }          
    }

    numList = (ListView) findViewById(R.id.list);
    btnAdd = (Button) findViewById(R.id.btnAdd);
    adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, list);
    numList.setAdapter(adapter);
    btnAdd.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            EditText edit = (EditText) findViewById(R.id.txtItem);
            spEditor.putString("Value["+count+"]", edit.getText().toString());
            spEditor.commit();
            list.add(preferences.getString("Value["+count+"]", ""));
            count += 1;
            spEditor.putInt("count", count);
            adapter.notifyDataSetChanged();

        }
    });
}