我想从数据库中检索特定的行。实际上，我有一个数据库中项目的列表视图，现在当我点击特定项目时，我想打开一个新活动，它显示属于特定项目的所有信息。
DBAdapter.java
package protect.my.password;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
// TO USE:
// Change the package (at top) to match your project.
// Search for "TODO", and make the appropriate changes.
public class DBAdapter {
/////////////////////////////////////////////////////////////////////
// Constants & Data
/////////////////////////////////////////////////////////////////////
// For logging:
private static final String TAG = "DBAdapter";
// DB Fields
public static final String KEY_ROWID = "_id";
public static final int COL_ROWID = 0;
/*
* CHANGE 1:
*/
// TODO: Setup your fields here:
public static final String KEY_WEBSITE = "website";
public static final String KEY_USERNAME = "username";
public static final String KEY_PASSWORD = "password";
// TODO: Setup your field numbers here (0 = KEY_ROWID, 1=...)
public static final int COL_WEBSITE = 1;
public static final int COL_USERNAME = 2;
public static final int COL_PASSWORD = 3;
public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_WEBSITE, KEY_USERNAME, KEY_PASSWORD};
// DB info: it's name, and the table we are using (just one).
public static final String DATABASE_NAME = "MyDb";
public static final String DATABASE_TABLE = "mainTable";
// Track DB version if a new version of your app changes the format.
public static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE_SQL =
"create table " + DATABASE_TABLE
+ " (" + KEY_ROWID + " integer primary key autoincrement, "
/*
* CHANGE 2:
*/
// TODO: Place your fields here!
// + KEY_{...} + " {type} not null"
// - Key is the column name you created above.
// - {type} is one of: text, integer, real, blob
// (http://www.sqlite.org/datatype3.html)
// - "not null" means it is a required field (must be given a value).
// NOTE: All must be comma separated (end of line!) Last one must have NO comma!!
+ KEY_WEBSITE + " text not null, "
+ KEY_USERNAME + " text not null, "
+ KEY_PASSWORD + " string not null"
// Rest of creation:
+ ");";
// Context of application who uses us.
private final Context context;
private DatabaseHelper myDBHelper;
private SQLiteDatabase db;
/////////////////////////////////////////////////////////////////////
// Public methods:
/////////////////////////////////////////////////////////////////////
public DBAdapter(Context ctx) {
this.context = ctx;
myDBHelper = new DatabaseHelper(context);
}
// Open the database connection.
public DBAdapter open() {
db = myDBHelper.getWritableDatabase();
return this;
}
// Close the database connection.
public void close() {
myDBHelper.close();
}
// Add a new set of values to the database.
public long insertRow(String website, String username, String password) {
/*
* CHANGE 3:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_WEBSITE, website);
initialValues.put(KEY_USERNAME, username);
initialValues.put(KEY_PASSWORD, password);
// Insert it into the database.
return db.insert(DATABASE_TABLE, null, initialValues);
}
// Delete a row from the database, by rowId (primary key)
public boolean deleteRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
return db.delete(DATABASE_TABLE, where, null) != 0;
}
public void deleteAll() {
Cursor c = getAllRows();
long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
if (c.moveToFirst()) {
do {
deleteRow(c.getLong((int) rowId));
} while (c.moveToNext());
}
c.close();
}
// Return all data in the database.
public Cursor getAllRows() {
String where = null;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Get a specific row (by rowId)
public Cursor getRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Change an existing row to be equal to new data.
public boolean updateRow(long rowId, String webSite, String userName, String passWord) {
String where = KEY_ROWID + "=" + rowId;
/*
* CHANGE 4:
*/
// TODO: Update data in the row with new fields.
// TODO: Also change the function's arguments to be what you need!
// Create row's data:
ContentValues newValues = new ContentValues();
newValues.put(KEY_WEBSITE, webSite);
newValues.put(KEY_USERNAME, userName);
newValues.put(KEY_PASSWORD, passWord);
// Insert it into the database.
return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}
/////////////////////////////////////////////////////////////////////
// Private Helper Classes:
/////////////////////////////////////////////////////////////////////
/**
* Private class which handles database creation and upgrading.
* Used to handle low-level database access.
*/
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(DATABASE_CREATE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading application's database from version " + oldVersion
+ " to " + newVersion + ", which will destroy all old data!");
// Destroy old database:
_db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
// Recreate new database:
onCreate(_db);
}
}
}
Listview.java
package protect.my.password;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class Listview extends Activity {
ListView listview;
ArrayAdapter<String> adapter;
DBAdapter myDb;
String website;
String password;
String username;
String row_id;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listview = (ListView) findViewById(R.id.dblist);
this.listview.setEmptyView(findViewById(R.id.emptyElement));
openDB();
listviewitems();
myDb.close();
}
private void listviewitems() {
Cursor cursor = myDb.getAllRows();
// populate the message from the cursor
// Reset cursor to start, checking to see if there's data:
// Process the data:
List<String> values = new ArrayList<String>();
if(cursor != null && cursor.moveToFirst()){
do {
row_id = cursor.getString(DBAdapter.COL_ROWID);
website = cursor.getString(DBAdapter.COL_WEBSITE);
username = cursor.getString(DBAdapter.COL_USERNAME);
password = cursor.getString(DBAdapter.COL_PASSWORD);
// Here I have to add the following code to use them all.
// values.add(website + " - " + username + " - " + password);
// } while(cursor.moveToNext());
values.add(website);
} while(cursor.moveToNext());
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, values);
listview.setAdapter(adapter);
listview.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent intent = new Intent(ReadActivity.this, ReadData.class);
intent.putExtra("RowID", row_id);
startActivity(intent);
}
});
// Close the cursor to avoid a resource leak.
cursor.close();
}
}
// Capture ListView item click
// OnItemClickListener viewNoteListener = new OnItemClickListener() {
// public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
// long arg3) {
//
// // Open ViewNote activity
// Intent intent = new Intent(ReadActivity.this, ReadData.class);
// // Pass the ROW_ID to ViewNote activity
// intent.putExtra("intVariableName", id);
// startActivity(intent);
// }
// };
private void openDB() {
myDb = new DBAdapter(this);
myDb.open();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.read, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
else if (id == R.id.add){
startActivity(new Intent("protect.my.password.WRITEACTIVITY"));
finish();
return true;
}
return false;
}
}
ReadData.java
package protect.my.password;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.widget.EditText;
public class ReadData extends Activity {
EditText et, et1, et2;
long member_id;
DBAdapter mydb;
String website2;
String username2;
String password2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.read_data);
mydb = new DBAdapter(this);
mydb.open();
et = (EditText) findViewById(R.id.editText3);
et1 = (EditText) findViewById(R.id.editText1);
et2 = (EditText) findViewById(R.id.editText2);
Intent intent = getIntent();
String RowID1 = intent.getExtras().getString("RowID");
member_id = Long.parseLong(RowID1);
Cursor cursor = mydb.getRow(member_id);
displayRecordSet(cursor);
et.setText(website2);
et1.setText(username2);
et2.setText(password2);
}
private void displayRecordSet(Cursor cursor) {
// TODO Auto-generated method stub
if(cursor != null && cursor.moveToFirst()){
do {
website2 = cursor.getString(DBAdapter.COL_WEBSITE);
username2 = cursor.getString(DBAdapter.COL_USERNAME);
password2 = cursor.getString(DBAdapter.COL_PASSWORD);
// Here I have to add the following code to use them all.
// values.add(website + " - " + username + " - " + password);
// } while(cursor.moveToNext());
} while(cursor.moveToNext());
cursor.close();
}
}
}
我尝试了很多东西，但它没有用。现在我已经删除了我为检索特定行而编写的代码，现在任何人都可以帮助我吗？欢迎任何帮助。
答案 0 :(得分：0)
我没有看到你在任何地方拨打getRow来获取特定行。您只需拨打getAllRows。如果您确实希望获得单行，请尝试调用您拥有的getRow(long rowId)。
编辑：
db.open();
Cursor c = db.getAllLocationDetails(alarmsSpinner.getSelectedItem().toString());
if (c.moveToFirst()) {
do {
alarmNumber = c.getString(c.getColumnIndex(DBAdapter.MY_LOCATION_NUMBER));
} while (c.moveToNext());
rgMessages.check(R.id.rbReceivedMessages);
loadMessages(alarmNumber);
}
c.close();
db.close();
这是我使用的东西。打开db.open()，然后从db调用所需的方法，例如db.getRow(theIdOfYourRow)。然后在if中检索你的行，并将其保存在我想要的alarmNumber变量中。