我创建了登录页面和注册页面。当我使用用户名和密码注册时，它会存储在数据库中。当我进入登录页面时，用户名和密码是从数据库中获取的。到目前为止一切正常。
之后，我想在登录成功时显示数据库中的列表视图数据。这是我的登录页面：
package com.example.uidesign;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class signinactivity extends Activity {
EditText edname,edpwd;
Button b;
LoginDataBaseAdapter logindatabaseadapter;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
logindatabaseadapter=new LoginDataBaseAdapter(this);
logindatabaseadapter=logindatabaseadapter.open();
edname=(EditText) findViewById(R.id.editTextUserNameToLogin);
edpwd=(EditText) findViewById(R.id.editTextPasswordToLogin);
b=(Button) findViewById(R.id.buttonSignIn);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String userName=edname.getText().toString();
String password=edpwd.getText().toString();
String storedpassword=logindatabaseadapter.getSinlgeEntry(userName);
if(password.equals(storedpassword))
{
Toast.makeText(signinactivity.this, "Logged in Successfully", Toast.LENGTH_LONG).show();
Intent i=new Intent(getApplicationContext(),CategoryListActivity.class);
startActivity(i);
}
else
{
Toast.makeText(signinactivity.this, "Password Does not match", Toast.LENGTH_LONG).show();
}
}
});
}
}
当显示“登录成功”消息时，我想转到列表视图数据库活动，该活动将在列表视图中显示数据。
这是我的 Listview 课程：
package com.example.uidesign;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
public class CategoryListActivity extends ListActivity {
ListView lists;
Button b;
ListAdapter la;
LoginDataBaseAdapter logindatabaseadapter;
protected void oncreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.categorieslist);
lists=(ListView) findViewById(R.id.lv);
logindatabaseadapter=new LoginDataBaseAdapter(this);
logindatabaseadapter=logindatabaseadapter.open();
List<String> values=logindatabaseadapter.getname();
ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,values);
setListAdapter(adapter);
}
}
这是我的数据库适配器类：
public List<String> getname()
{
String [] column=new String[] {"ID","NAME"};
Cursor c=db.query("category", column, null,null, null, null, null);
List<String> li=new ArrayList<String>();
int irow=c.getColumnIndex("ID");
int iname=c.getColumnIndex("NAME");
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
li.add(c.getString(irow)+" "+c.getString(iname));
}
return li;
}
这是 dbhelper 类。在此我有两个表，一个用于存储登录信息。另一个用于列表视图。Dbhelper 类：
package com.example.uidesign;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper extends SQLiteOpenHelper
{
public DataBaseHelper(Context context, String name,CursorFactory factory, int version)
{
super(context, name, factory, version);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
@Override
public void onCreate(SQLiteDatabase _db)
{
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE);
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE1);
ContentValues cv=new ContentValues();
cv.put("NAME", "TAXI");
_db.insert("category", null, cv);
cv.put("NAME", "FOOD ORDERING");
_db.insert("category", null, cv);
cv.put("NAME", "HOSPITAL");
_db.insert("category", null, cv);
cv.put("NAME", "TICKET BOOKING");
_db.insert("category", null, cv);
cv.put("NAME", "POLICE");
_db.insert("category", null, cv);
cv.put("NAME", "EMERGENCY");
_db.insert("category", null, cv);
}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
@Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion)
{
// Log the version upgrade.
Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data");
// Upgrade the existing database to conform to the new version. Multiple
// previous versions can be handled by comparing _oldVersion and _newVersion
// values.
// The simplest case is to drop the old table and create a new one.
_db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
_db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
// Create a new one.
onCreate(_db);
}
}
这是我的整体适配器类。登录数据库适配器类：
package com.example.uidesign;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class LoginDataBaseAdapter
{
static final String DATABASE_NAME = "login.db";
static final int DATABASE_VERSION = 1;
public static final int NAME_COLUMN = 1;
// TODO: Create public field for each column in your table.
// SQL Statement to create a new database.
static final String DATABASE_CREATE = "create table "+"LOGIN"+
"( " +"ID"+" integer primary key autoincrement,"+ "USERNAME text,PASSWORD text); ";
static final String DATABASE_CREATE1="create table "+"category"+"(" +"ID" + " integer primary key autoincrement, " + "NAME text);";
// Variable to hold the database instance
public SQLiteDatabase db;
// Context of the application using the database.
private final Context context;
// Database open/upgrade helper
private DataBaseHelper dbHelper;
public LoginDataBaseAdapter(Context _context)
{
context = _context;
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public LoginDataBaseAdapter open() throws SQLException
{
db = dbHelper.getWritableDatabase();
return this;
}
public void close()
{
db.close();
}
public SQLiteDatabase getDatabaseInstance()
{
return db;
}
public List<String> getname()
{
String [] column=new String[] {"ID","NAME"};
Cursor c=db.query("category", column, null,null, null, null, null);
List<String> li=new ArrayList<String>();
int irow=c.getColumnIndex("ID");
int iname=c.getColumnIndex("NAME");
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
li.add(c.getString(irow)+" "+c.getString(iname));
}
return li;
}
public void insertEntry(String userName,String password)
{
ContentValues newValues = new ContentValues();
// Assign values for each row.
newValues.put("USERNAME", userName);
newValues.put("PASSWORD",password);
// Insert the row into your table
db.insert("LOGIN", null, newValues);
///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
}
public int deleteEntry(String UserName)
{
//String id=String.valueOf(ID);
String where="USERNAME=?";
int numberOFEntriesDeleted= db.delete("LOGIN", where, new String[]{UserName}) ;
// Toast.makeText(context, "Number fo Entry Deleted Successfully : "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show();
return numberOFEntriesDeleted;
}
public String getSinlgeEntry(String userName)
{
Cursor cursor=db.query("LOGIN", null, " USERNAME=?", new String[]{userName}, null, null, null);
if(cursor.getCount()<1) // UserName Not Exist
{
cursor.close();
return "NOT EXIST";
}
cursor.moveToFirst();
String password= cursor.getString(cursor.getColumnIndex("PASSWORD"));
cursor.close();
return password;
}
public void updateEntry(String userName,String password)
{
// Define the updated row content.
ContentValues updatedValues = new ContentValues();
// Assign values for each row.
updatedValues.put("USERNAME", userName);
updatedValues.put("PASSWORD",password);
String where="USERNAME = ?";
db.update("LOGIN",updatedValues, where, new String[]{userName});
}
}