【发布时间】：2012-10-20 16:54:34
【问题描述】：
我尝试从我创建的数据库中读取数据，并在自定义 ListView 中连续显示一些数据。 我不明白我的错误是什么。
这是我的代码：
public class EsodaMainActivity extends Activity
{
public static final String ROW_ID = "row_id"; //Intent extra key
private ListView esodaListView; // the ListActivitys ListView
private SimpleCursorAdapter esodaAdapter; // adapter for ListView
DatabaseConnector databaseConnector = new DatabaseConnector(EsodaMainActivity.this);
// called when the activity is first created
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_esoda_main);
esodaListView = (ListView)findViewById(R.id.esodaList);
esodaListView.setOnItemClickListener(viewEsodaListener);
databaseConnector.open();
//Cursor cursor= databaseConnector.query("esoda", new String[]
// {"name", "amount"}, null,null,null);
Cursor cursor=databaseConnector.getAllEsoda();
startManagingCursor(cursor);
// map each esoda to a TextView in the ListView layout
// The desired columns to be bound
String[] from = new String[] {"name","amount"}; // built an String array named "from"
//The XML defined views which the data will be bound to
int[] to = new int[] { R.id.esodaTextView, R.id.amountTextView}; // built an int array named "to"
// EsodaMainActivity.this = The context in which the ListView is running
// R.layout.esoda_list_item = Id of the layout that is used to display each item in ListView
// null =
// from = String array containing the column names to display
// to = Int array containing the column names to display
esodaAdapter = new SimpleCursorAdapter (this, R.layout.esoda_list_item, cursor, from, to);
esodaListView.setAdapter(esodaAdapter); // set esodaView's adapter
} // end of onCreate method
@Override
protected void onResume()
{
super.onResume(); // call super's onResume method
// create new GetEsodaTask and execute it
// GetEsodaTask is an AsyncTask object
new GetEsodaTask().execute((Object[]) null);
} // end of onResume method
// onStop method is executed when the Activity is no longer visible to the user
@Override
protected void onStop()
{
Cursor cursor= esodaAdapter.getCursor(); // gets current cursor from esodaAdapter
if (cursor != null)
cursor.deactivate(); // deactivate cursor
esodaAdapter.changeCursor(null); // adapter now has no cursor (removes the cursor from the CursorAdapter)
super.onStop();
} // end of onStop method
// this class performs db query outside the GUI
private class GetEsodaTask extends AsyncTask<Object, Object, Cursor>
{
// we create a new DatabaseConnector obj
// EsodaMainActivity.this = Context
DatabaseConnector databaseConnector = new DatabaseConnector(EsodaMainActivity.this);
// perform the db access
@Override
protected Cursor doInBackground(Object... params)
{
databaseConnector.open();
// get a cursor containing call esoda
return databaseConnector.getAllEsoda();
// the cursor returned by getAllContacts() is passed to method onPostExecute()
} // end of doInBackground method
// here we use the cursor returned from the doInBackground() method
@Override
protected void onPostExecute(Cursor result)
{
esodaAdapter.changeCursor(result); // set the adapter's Cursor
databaseConnector.close();
} // end of onPostExecute() method
} // end of GetEsodaTask class
// creates the Activity's menu from a menu resource XML file
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
super.onCreateOptionsMenu(menu);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.esoda_menu, menu); // inflates(εμφυσώ) esodamainactivity_menu.xml to the Options menu
return true;
} // end of onCreateOptionsMenu() method
//handles choice from options menu - is executed when the user touches a MenuItem
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
// creates a new Intent to launch the AddEditEsoda Activity
// EsodaMainActivity.this = Context from which the Activity will be launched
// AddEditEsoda.class = target Activity
Intent addNewEsoda = new Intent(EsodaMainActivity.this, AddEditEsoda.class);
startActivity(addNewEsoda);
return super.onOptionsItemSelected(item);
} // end of method onPtionsItemSelected()
// event listener that responds to the user touching a esoda's name in the ListView
OnItemClickListener viewEsodaListener = new OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3)
{
// create an intent to launch the ViewEsoda Activity
Intent viewEsoda = new Intent(EsodaMainActivity.this, ViewEsoda.class);
// pass the selected esoda's row ID as an extra with the Intent
viewEsoda.putExtra(ROW_ID, arg3);
startActivity(viewEsoda); // start viewEsoda.class Activity
} // end of onItemClick() method
}; // end of viewEsodaListener
} // end of EsodaMainActivity class
声明：Cursor cursor=databaseConnector.getAllEsoda();
查询所有数据（列）
从我想在我的自定义 ListView 2 中显示的数据中：“名称”和“金额”。
但我仍然收到调试器错误。
请帮忙。
你的意思是来自调试器的消息？
Esoda [Android 应用程序] DalvikVM[localhost:8603] 线程 [ main]（暂停（异常 RuntimeException））
ActivityThread.performLaunchActivity(ActivityThread$ActivityRecord, 意图）线路：2663
ActivityThread.handleLaunchActivity(ActivityThread$ActivityRecord, Intent) 行：2679 ActivityThread.access$2300(ActivityThread, ActivityThread$ActivityRecord, Intent) 行：125
ActivityThread$H.handleMessage(Message) 行：2033
ActivityThread$H(Handler).dispatchMessage(Message) 行：99 Looper.loop() 行：123 ActivityThread.main(String[]) 行： 第4627章 int, boolean) 行：不可用 [本机方法] Method.invoke(Object, Object...) 行：521
ZygoteInit$MethodAndArgsCaller.run() 行：868
ZygoteInit.main(String[]) 行：626 NativeStart.main(String[]) 行：不可用 [本机方法] 线程 [ Binder 线程 #2] （运行中）线程 [ Binder 线程 #1]（运行中）
这里是 LogCat：
10-20 21:53:19.903: W/ActivityThread(1973): Application development.nk.esoda is waiting for the debugger on port 8100...
10-20 21:53:19.933: I/System.out(1973): Sending WAIT chunk
10-20 21:53:19.943: I/dalvikvm(1973): Debugger is active
10-20 21:53:19.953: I/System.out(1973): Debugger has connected
10-20 21:53:19.953: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:20.215: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:20.478: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:20.673: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:20.890: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:21.133: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:21.333: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:21.573: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:21.790: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:21.995: I/System.out(1973): waiting for debugger to settle...
10-20 21:53:22.198: I/System.out(1973): debugger has settled (1497)
【问题讨论】：
-
调试器错误是什么意思？
-
您能否附上 LogCat 输出，以便我们知道您遇到了什么错误？
-
请发布所有 LogCat 错误。在 Eclipse 中，您只需突出显示该行并按 Ctrl-C 即可复制它们。