安卓sqlite排序列表视图使用单选按钮

Question

我创建了一个列表视图，数据取自sqlite现在我想让它将使用单选按钮按名称或位置排序

这是我的代码

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
db = new DatabaseHelper(this);
RadioButton rbname = (RadioButton)findViewById(R.id.radio0);
RadioButton rblocation = (RadioButton)findViewById(R.id.radio1);
if (rbname.isChecked()){
Cursor = db
.getReadableDatabase()
.rawQuery("SELECT *  FROM " + DatabaseHelper.LIST + " ORDER BY " + DatabaseHelper.NAME, null);  
ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.row, Cursor,
new String[] {DatabaseHelper.NAME, DatabaseHelper.ADDRESS, DatabaseHelper.GENDER, DatabaseHelper.LOCATION},
new int[] {R.id.txtName, R.id.txtAddress, R.id.txtGender, R.id.txtLocation});       
setListAdapter(adapter);
}
else if (rblocation.isChecked()){
Cursor = db
.getReadableDatabase()
.rawQuery("SELECT *  FROM " + DatabaseHelper.LIST+ " ORDER BY " + DatabaseHelper.LOCATION, null);   
ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.row, Cursor,
new String[] {DatabaseHelper.NAME, DatabaseHelper.ADDRESS, DatabaseHelper.GENDER, DatabaseHelper.LOCATION},
new int[] {R.id.txtName, R.id.txtAddress, R.id.txtGender, R.id.txtLocation});       
setListAdapter(adapter);
}

registerForContextMenu(getListView());
}

我已经尝试放置Cursor.requery()，并且已经尝试将ListAdapter更改为BaseAdapter所以我可以使用notifydatasetchanged()

但是什么也没发生。。我的列表视图仍然没有更新

请帮我解决这个问题

Answer 1

您需要做的是将代码放入监听器中，以便在单击按钮后激活事件，而不是在onCreate中激活一次。此外，通过重新实例化游标并在适配器上调用changeCursor，还可以更改由游标支持的列表视图。我希望下面的代码能让事情变得更清楚：

private RadioButton rbname, rblocation;
private SimpleCursorAdapter adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
db = new DatabaseHelper(this);
rbname = (RadioButton)findViewById(R.id.radio0);
rblocation = (RadioButton)findViewById(R.id.radio1);
Cursor cursor = db
.getReadableDatabase()
.rawQuery("SELECT *  FROM " + DatabaseHelper.LIST + " ORDER BY " + DatabaseHelper.NAME, null);
// a default cursor
adapter = new SimpleCursorAdapter(this, R.layout.row, Cursor,
new String[] {DatabaseHelper.NAME, DatabaseHelper.ADDRESS, DatabaseHelper.GENDER, DatabaseHelper.LOCATION},
new int[] {R.id.txtName, R.id.txtAddress, R.id.txtGender, R.id.txtLocation});       
setListAdapter(adapter);    // do the adapter stuff here to avoid repeating code
initListeners(); // set up the listeners for the radio buttons
registerForContextMenu(getListView());
}
private void initListeners() {
rbname.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked){
Cursor cursor = db
.getReadableDatabase()
.rawQuery("SELECT *  FROM " + DatabaseHelper.LIST + " ORDER BY " + DatabaseHelper.NAME, null);
adapter.changeCursor(cursor); // change cursor in adapter so that listview changes                  
}               
}
});
rblocation.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked){
Cursor cursor = db
.getReadableDatabase()
.rawQuery("SELECT *  FROM " + DatabaseHelper.LIST+ " ORDER BY " + DatabaseHelper.LOCATION, null);   
adapter.changeCursor(cursor);   
}               
}
});
}

Answer 2

我很久以前也遇到过同样的问题，帮助我生成了一个刷新方法。所以每次我需要刷新时，我都简单地调用这个方法。

private void refresh() {
ListView yourListView = getListView();   
list = getList(); //this is a List<string>
adapter = new ArrayAdapter<String> (this,R.layout.your_listview_item,list); //this is ArrayAdapter<String>       
yourListView.setAdapter(adapter);
yourListView.invalidateViews();
}

这在我的ListActivity 中运行良好