我一直在尝试使用下面的代码从SQLite数据库填充Android Listview。我已经从同一个类中的数组成功完成了这个。但在这种情况下，我试图从我从另一个类返回的String数组中填充它。我是新手，所以我可能完全错了。如果有人能够查看代码并告诉我我做错了什么就会很棒。
任何帮助都会非常感激，因为我正面临严峻的压力要完成它，谢谢！
LoginActivity Class
公共类LoginActivity扩展了Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
final EditText txtUserName = (EditText)findViewById(R.id.txtUsername);
final EditText txtPassword = (EditText)findViewById(R.id.txtPassword);
Button btnLogin = (Button)findViewById(R.id.btnLogin);
btnLogin.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
String username = txtUserName.getText().toString();
String password = txtPassword.getText().toString();
try{
if(username.length() > 0 && password.length() >0)
{
DBUserAdapter dbUser = new DBUserAdapter(LoginActivity.this);
dbUser.open();
int UID = dbUser.Login(username, password);
if(UID != -1)
{
// TEST
//int UID = dbUser.getUserID(username, password);
//getSitesByClientname(UID);
// END TEST
// MY TEST CODE TO CHANGE ACTIVITY TO CLIENT SITES
Intent myIntent = new Intent(LoginActivity.this, ClientSites.class);
//Intent myIntent = new Intent(getApplicationContext(), ClientSites.class);
myIntent.putExtra("userID", UID);
startActivity(myIntent);
//finish();
// END MY TEST CODE
//Cursor UserID = dbUser.getUserID();
Toast.makeText(LoginActivity.this,"Successfully Logged In", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(LoginActivity.this,"Invalid Username/Password", Toast.LENGTH_LONG).show();
}
dbUser.close();
}
}catch(Exception e)
{
Toast.makeText(LoginActivity.this,e.getMessage(), Toast.LENGTH_LONG).show();
}
}
});
}
}
从 DBHelper类返回字符串数组
的方法public String[] getSitesByClientname(String id) {
String[] args={id};
//return db.rawQuery("SELECT client_sitename FROM " + CLIENT_SITES_TABLE + " WHERE client_id=?", args);
Cursor myCursor = db.rawQuery("SELECT client_sitename FROM " + CLIENT_SITES_TABLE + " WHERE client_id=?", args);
// loop through all rows and adding to array
int count;
count = myCursor.getCount();
final String[] results = new String[count];
results[0] = new String();
int i = 0;
try{
if (myCursor.moveToFirst()) {
do {
results[i] = myCursor.getString(myCursor.getColumnIndex("client_sitename"));
} while (myCursor.moveToNext());
}
}finally{
myCursor.close();
}
db.close();
// return results array
return results;
ClientSites类
公共类ClientSites扩展了ListActivity {
public final static String ID_EXTRA="com.example.loginfromlocal._ID";
private DBUserAdapter dbHelper = null;
//private Cursor ourCursor = null;
private ArrayAdapter<String> adapter=null;
//@SuppressWarnings("deprecation")
@SuppressLint("NewApi")
public void onCreate(Bundle savedInstanceState) {
try
{
super.onCreate(savedInstanceState);
//setContentView(R.layout.client_sites);
Intent i = getIntent();
String uID = String.valueOf(i.getIntExtra("userID", 0));
//int uID = i.getIntExtra("userID", 0);
//ListView myListView = (ListView)findViewById(R.id.myListView);
dbHelper = new DBUserAdapter(this);
dbHelper.createDatabase();
//dbHelper.openDataBase();
dbHelper.open();
String[] results = dbHelper.getSitesByClientname(uID);
//setListAdapter(new ArrayAdapter<String>(ClientSites.this, R.id.myListView, results));
//adapter = new ArrayAdapter<String>(ClientSites.this, R.id.myListView, results);
setListAdapter(new ArrayAdapter<String>(ClientSites.this, R.layout.client_sites, results));
//ListView myListView = (ListView)findViewById(R.id.myListView);
ListView listView = getListView();
listView.setTextFilterEnabled(true);
//@SuppressWarnings("deprecation")
//SimpleCursorAdapter adapter = new SimpleCursorAdapter(getBaseContext(), R.id.myListView, null, null, null);
//CursorAdapter adapter = new SimpleCursorAdapter(this, R.id.myListView, null, null, null, 0);
//adapter = new Adapter(ourCursor);
//Toast.makeText(ClientSites.this, "Booo!!!", Toast.LENGTH_LONG).show();
//myListView.setAdapter(adapter);
//myListView.setOnItemClickListener(onListClick);
}
catch (Exception e)
{
Log.e("ERROR", "XXERROR IN CODE: " + e.toString());
e.printStackTrace();
}
}
}
对此有任何帮助都很棒，谢谢！
答案 0 :(得分：0)
创建自己的项目，活动很少。开始使用sqlite数据库
创建新应用程序。创建登录活动和数据库帮助程序。试图从DB上传dada。研究和发展 以下是如何使用SQLite DB的示例。
public class DBHelper extends SQLiteOpenHelper {
private static DBHelper instance;
private static final String DATABASE_NAME = "UserClientBase";
private static final int DATABASE_VERSION = 1;
public static interface USER extends BaseColumns {
String TABLE_NAME = "userTable";
String NAME = "userName";
String PASSWORD = "userPassword";
}
public static interface CLIENT extends BaseColumns {
String TABLE_NAME = "clientTable";
String NAME = "clientName";
String USER_ID = "userId";
}
private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS ";
private static final String DROP_TABLE = "DROP TABLE IF EXISTS ";
private static final String UNIQUE = "UNIQUE ON CONFLICT ABORT";
private static final String CREATE_TABLE_USER = CREATE_TABLE + USER.TABLE_NAME + " (" + USER._ID
+ " INTEGER PRIMARY KEY, " + USER.NAME + " TEXT " + UNIQUE + ", " + USER.PASSWORD + " TEXT);";
private static final String CREATE_TABLE_CLIENT = CREATE_TABLE + CLIENT.TABLE_NAME + " (" + CLIENT._ID
+ " INTEGER PRIMARY KEY, " + CLIENT.NAME + " TEXT UNIQUE, " + CLIENT.USER_ID + " INTEGER);";
private DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public static DBHelper getInstance(Context context) {
if (instance == null) {
instance = new DBHelper(context);
}
return instance;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE_USER);
db.execSQL(CREATE_TABLE_CLIENT);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(DROP_TABLE + USER.TABLE_NAME);
db.execSQL(DROP_TABLE + CLIENT.TABLE_NAME);
onCreate(db);
}
public long createUser(String newUserName, String newUserPassword) {
ContentValues values = new ContentValues();
values.put(USER.NAME, newUserName);
values.put(USER.PASSWORD, newUserPassword);
return getWritableDatabase().insert(USER.TABLE_NAME, null, values);
}
public long createClient(long userId, String newClientName) {
ContentValues values = new ContentValues();
values.put(CLIENT.USER_ID, userId);
values.put(CLIENT.NAME, newClientName);
return getWritableDatabase().insert(CLIENT.TABLE_NAME, null, values);
}
public boolean isCorrectLoginPassword(String login, String password) {
Cursor userListCursor = getReadableDatabase().rawQuery(
"SELECT * FROM " + USER.TABLE_NAME + " WHERE " + USER.NAME + " =? AND " + USER.PASSWORD
+ " =?", new String[] { login, password });
if ((userListCursor != null) && (userListCursor.getCount() > 0)) {
return true;
} else {
return false;
}
}
public Cursor getUserClientList(String userName) {
Cursor userClientList = getReadableDatabase().rawQuery(
"SELECT * FROM " + CLIENT.TABLE_NAME + " INNER JOIN " + USER.TABLE_NAME
+ " ON " + CLIENT.USER_ID + " = " + USER.TABLE_NAME + "." + USER._ID + " WHERE "
+ USER.NAME + " =?", new String[] { userName });
return userClientList;
}
}
Example of login button click listener.
String login = loginEdt.getText().toString();
String password = passwordEdt.getText().toString();
boolean loginSuccess = databaseHelper.isCorrectLoginPassword(login, password);
if(loginSuccess) {
Intent clientListIntent = new Intent(LoginActivity.this, ClientListActivity.class);
clientListIntent.putExtra(ClientListActivity.EXTRAS_LOGIN, login);
startActivity(clientListIntent);
} else {
Toast.makeText(LoginActivity.this, "Incorrect login/password", Toast.LENGTH_SHORT).show();
}
And example of listview with data from sql:
clientLv= (ListView)findViewById(R.id.listClient);
login = getIntent().getExtras().getString(EXTRAS_LOGIN);
dbHelper = DBHelper.getInstance(this);
Cursor clientList = dbHelper.getUserClientList(login);
adapter = new SimpleCursorAdapter(this, R.layout.row_client, clientList, new String[]{DBHelper.CLIENT.NAME}, new int[]{R.id.txtClientName} , SimpleCursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
clientLv.setAdapter(adapter);