我正在处理一个像应用程序这样的通讯录。我有一个数据库，我想在 ListView 中显示数据。谁能告诉我如何实现这一目标？以下是我到目前为止尝试过的，
public class Contacts {
private int id;
private String name;
private String phone_number;
private String email;
public Contacts()
{
}
public Contacts(int id, String name, String phone_number, String email)
{
this.id = id;
this.name = name;
this.phone_number = phone_number;
this.email = email;
}
public Contacts(String name, String phone_number, String email)
{
this.name = name;
this.phone_number = phone_number;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhone_number() {
return phone_number;
}
public void setPhone_number(String phone_number) {
this.phone_number = phone_number;
}
public void setEmail(String email) {
this.email = email;
}
public String getEmail() {
return email;
}
}
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 2;
private static final String DATABASE_NAME = "ContactsManager";
private static final String TABLE_CONTACTS = "contacts";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
private static final String KEY_EMAIL = "email";
public DatabaseHandler(Context context) {
super( context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_PH_NO + " TEXT," + KEY_EMAIL + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
onCreate(db);
}
public void insertContact(Contacts contacts)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(KEY_NAME, contacts.getName()); // Contact Name
cv.put(KEY_PH_NO, contacts.getPhone_number()); // Contact Phone
cv.put(KEY_EMAIL, contacts.getEmail()); //Contact Email
// Inserting Row
db.insert(TABLE_CONTACTS, null, cv);
db.close();
}
// Getting All Contacts
public List<Contacts> getAllContacts()
{
List<Contacts> contactList = new ArrayList<Contacts>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst())
{
do {
Contacts contact = new Contacts();
//contact.setId(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setPhone_number(cursor.getString(2));
contact.setEmail(cursor.getString(3));
// Adding contact to list
contactList.add(contact);
}
while (cursor.moveToNext());
}
// return contact list
return contactList;
}
}
public class View_data extends ListActivity {
DatabaseHandler db = new DatabaseHandler(this);
Cursor c ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_data);
db.getWritableDatabase();
List<Contacts> values = db.getAllContacts();
ArrayAdapter<Contacts> adapter = new ArrayAdapter<Contacts>(this,
android.R.layout.simple_list_item_1, values);
setListAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.view_data, menu);
return true;
}
}
在View_data课堂上，我试图显示数据但做不到。任何建议将不胜感激。