我的mainactivity列表视图显示了数据库中的项目。我在操作栏中有一个添加按钮。单击添加按钮时，弹出一个对话框，用户填写新项目的字段，然后单击＆＃34;添加＆＃34;并将项目添加到数据库中。唯一的问题是mainactivity的listview没有更新以显示新项目。我可以关闭应用程序并重新打开它，然后我会看到新项目。它只是不立即更新。 （删除项目时出现同样的问题，只有删除发生在LongPress上）
Mainactivity.java
package blah.blah.blah
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.TextView;
public class InitActivity extends FragmentActivity {
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
// Gets the data repository in write mode
PlayersDBHelper mDbHelper = new PlayersDBHelper(getBaseContext());
SQLiteDatabase db = mDbHelper.getWritableDatabase();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_init);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}//End onCreate()
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.init, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_add:
showAddPlayerDialog();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void showAddPlayerDialog() {
// Create an instance of the dialog fragment and show it
DialogFragment dialog = new addPlayerDialog();
dialog.show(this.getFragmentManager(), "addPlayerFragment");
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
if(position == 0) {
Fragment playersFragment = new PlayersFragment();
return playersFragment;
} else if(position == 1){
Fragment otherFragment= new otherFragment();
return otherFragment;
} else {
Fragment otherFragment2 = new otherFragment2();
return otherFragment2;
}
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}//End sectionsPagerAdapter()
public static class PlayersFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public int myFragmentId = 1;
private ListView mylistview;
private String[] values;
public ArrayAdapter<String> adapter;
public PlayersFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_players,
container, false);
mylistview = (ListView) rootView.findViewById(R.id.myListView);
registerForContextMenu(mylistview);
PlayersDBHelper mDbHelper = new PlayersDBHelper(rootView.getContext());
SQLiteDatabase db = mDbHelper.getReadableDatabase();
// Define a projection that specifies which columns from the database
// you will actually use after this query.
String[] projection = {
PlayerEntry._ID,
PlayerEntry.COLUMN_NAME_ID,
PlayerEntry.COLUMN_NAME_NAME,
PlayerEntry.COLUMN_NAME_POSITION
};
String selection = null; //Null will return all rows for given table
String[] selectionArgs = null; //Null should return all data
// How you want the results sorted in the resulting Cursor
String sortOrder =
PlayerEntry.COLUMN_NAME_NAME + " DESC";
Cursor c = db.query(
PlayerEntry.TABLE_NAME, // The table to query
projection, // The columns to return
selection, // The columns for the WHERE clause
selectionArgs, // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
sortOrder // The sort order
);
values = new String[] {};
String array[] = new String[c.getCount()];
int i = 0;
c.moveToFirst();
while (c.isAfterLast() == false) {
array[i] = c.getString(c.getColumnIndexOrThrow(PlayerEntry.COLUMN_NAME_NAME));
i++;
c.moveToNext();
}
for(int x = 0; x < array.length ; x++){
Log.d("Logan", "Entry at:" + x + " is " + array[x]);
values = push(values, array[x]);
}
adapter = new ArrayAdapter<String>(this.getActivity(),
android.R.layout.simple_list_item_1, values);
mylistview.setAdapter(adapter);
return rootView;
}
private static String[] push(String[] array, String push) {
String[] longer = new String[array.length + 1];
for (int i = 0; i < array.length; i++)
longer[i] = array[i];
longer[array.length] = push;
return longer;
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
if (v.getId()==R.id.myListView) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)menuInfo;
menu.setHeaderTitle(values[info.position]);
String[] menuItems = {"Edit", "Delete"};
for (int i = 0; i<menuItems.length; i++) {
menu.add(Menu.NONE, i, i, menuItems[i]);
}
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
PlayersDBHelper mDbHelper = new PlayersDBHelper(getActivity());
final SQLiteDatabase db = mDbHelper.getWritableDatabase();
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
int menuItemIndex = item.getItemId();
String[] menuItems = {"Edit", "Delete"};
String menuItemName = menuItems[menuItemIndex];
String listItemName = values[info.position];
if(menuItemName.equalsIgnoreCase("Edit")) {
} else {
//menuItemName === Delete
// Define 'where' part of query.
String selection = PlayerEntry.COLUMN_NAME_NAME + " =? ";
// Specify arguments in placeholder order.
String[] selectionArgs = { listItemName };
// Issue SQL statement.
db.delete(PlayerEntry.TABLE_NAME, selection, selectionArgs);
adapter.notifyDataSetChanged();
}
return true;
}
}
public static class otherFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public otherFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_lineup,
container, false);
return rootView;
}
}
public static class otherFragment2 extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public otherFragment2() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_position,
container, false);
return rootView;
}
}
}
addPlayerDialog.java
package blah.blah.blah;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.text.Editable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
public class addPlayerDialog extends DialogFragment{
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Gets the data repository in write mode
PlayersDBHelper mDbHelper = new PlayersDBHelper(getActivity().getBaseContext());
final SQLiteDatabase db = mDbHelper.getWritableDatabase();
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
final LayoutInflater inflater = getActivity().getLayoutInflater();
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
final View view = inflater.inflate(R.layout.addplayerdialog, null);
final ListView list = (ListView)view.findViewById(R.id.myListView);
builder.setView(view)
// Add action buttons
.setPositiveButton(R.string.add, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int id) {
// sign in the user ...
EditText fName = (EditText) view.findViewById(R.id.editFirstName);
Editable firstName = fName.getText();
EditText lName = (EditText) view.findViewById(R.id.editLastName);
Editable lastName = lName.getText();
EditText number = (EditText) view.findViewById(R.id.playerNumber);
int num = Integer.parseInt(number.getText().toString());
Spinner spinner = (Spinner) view.findViewById(R.id.positionSpinner);
String position = spinner.getSelectedItem().toString();
// Create a new map of values, where column names are the keys
ContentValues values = new ContentValues();
values.put(PlayerEntry.COLUMN_NAME_ID, num);
values.put(PlayerEntry.COLUMN_NAME_NAME, firstName + " " + lastName);
values.put(PlayerEntry.COLUMN_NAME_POSITION, position);
// Insert the new row, returning the primary key value of the new row
long newRowId;
newRowId = db.insert(
PlayerEntry.TABLE_NAME,
null,
values);
//**** HERE IS WHERE I THINK THE CHANGE NEEDS TO BE! ****
((ArrayAdapter) list.getAdapter()).notifyDataSetChanged();
}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
Spinner spinner = (Spinner) view.findViewById(R.id.positionSpinner);
// Create an ArrayAdapter using the string array and a default spinner layout
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getActivity(),
R.array.positions, android.R.layout.simple_spinner_item);
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
spinner.setAdapter(adapter);
return builder.create();
}
}
addPlayerDialog.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/editFirstName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="@string/fName" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/editLastName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="@string/lName" />
<EditText
android:id="@+id/playerNumber"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="@string/playerNumberHint"
android:inputType="number" />
<Spinner
android:id="@+id/positionSpinner"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
答案 0 :(得分：1)
我认为您已将数据插入数据库但忘记在致电yourListViewAdapter.add之前调用notifyDataSetChanged方法