[英]Android SQLite search by name
我從這里開始使用Android中的SQLite示例: http : //www.cnblogs.com/pangblog/p/3327696.html
我嘮叨着通過名字聯系。 如何更改GetContact函數以按名稱搜索?
數據庫處理器:
public class DatabaseHandler extends SQLiteOpenHelper {
//Database Version
private static final int DATABASE_VERSION = 1;
//Database Name
private static final String DATABASE_NAME = "contactsManager";
//Contacts table name
private static final String TABLE_CONTACTS = "contacts";
//Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NUM = "phone_number";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables : CREATE TABLE table_name (column_name column_type);
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_PH_NUM + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
//Adding new contact
void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
values.put(KEY_PH_NUM, contact.getPhoneNumber()); // Contact Phone
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
Contact getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NUM }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
return contact;
}
// Getting All Contacts
public List<Contact> getAllContacts() {
List<Contact> contactList = new ArrayList<Contact>();
// Select All Query :SELECT * FROM tableName WHERE criteria
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 {
Contact contact = new Contact();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setPhoneNumber(cursor.getString(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
return contactList;
}
}
聯系:
public class Contact {
int _id;
String _name;
String _phone_number;
public Contact() {
}
public Contact(int id, String name, String phone_number) {
this._id = id;
this._name = name;
this._phone_number = phone_number;
}
public Contact(String name, String phone_number) {
this._name = name;
this._phone_number = phone_number;
}
public int getID() {
return this._id;
}
public void setID(int id) {
this._id = id;
}
public String getName() {
return this._name;
}
public void setName(String name) {
this._name = name;
}
public String getPhoneNumber() {
return this._phone_number;
}
public void setPhoneNumber(String phone_number) {
this._phone_number = phone_number;
}
}
getContact中數據庫查詢中的where子句當前是id = ?
和?
被id參數替換。 按名稱搜索需要做的是修改該部分。
// Getting single contact
Contact getContact(String name) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NUM }, KEY_NAME + "=?",
new String[] { name }, null, null, null, null);
//...
您還應該更改“工作”代碼,因為它不是很安全。 游標不能為null
(實際上),但如果數據庫中沒有這樣的名稱, cursor.moveToFirst()
可能會失敗。 如果失敗,您將在cursor.getString(0)
處獲得異常,因為游標沒有行來從中獲取數據。
刪除null
檢查,並檢查光標是否可以移動到第一個位置(不為空)。 一旦不再需要它,你也應該關閉光標。
Contact contact = null;
if (cursor.moveToFirst()) {
contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
}
cursor.close();
// can return null if no contact was found.
return contact;
http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html#query(java.lang.String,java.lang.String [],java.lang.String,java.lang.String [ ],java.lang.String,java.lang.String,java.lang.String,java.lang.String)
使用文檔。
使
db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NUM }, KEY_NAME+ "=?",
new String[] { String.valueOf(NAME) }, null, null, null, null);
並在函數頭部推送變量NAME。
您可以在SQLite中按照以下代碼進行搜索;
在MainActivity中;
search.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
public void onTextChanged(CharSequence s, int start, int before, int count) {
adapter.getFilter().filter(s.toString());
}
});
adapter.setFilterQueryProvider(new FilterQueryProvider() {
public Cursor runQuery(CharSequence constraint) {
return
//Here you can filter data by any row , just change text replace of "subject"
dbManager.fetchdatabyfilter(constraint.toString(),"subject");
}
});
DatabaseHelper.java
public Cursor fetchdatabyfilter(String inputText,String filtercolumn) throws SQLException {
Cursor row = null;
String query = "SELECT * FROM "+DatabaseHelper.TABLE_NAME;
if (inputText == null || inputText.length () == 0) {
row = database.rawQuery(query, null);
}else {
query = "SELECT * FROM "+DatabaseHelper.TABLE_NAME+" WHERE "+filtercolumn+" like '%"+inputText+"%'";
row = database.rawQuery(query, null);
}
if (row != null) {
row.moveToFirst();
}
return row;
}
EditText et = (EditText) findViewById(R.id.myFilter); et.addTextChangedListener(new TextWatcher() { public void afterTextChanged(Editable s) { } public void beforeTextChanged(CharSequence s, int start, int count, int after) { } public void onTextChanged(CharSequence s, int start, int before, int count) { adapter.getFilter().filter(s.toString()); } }); adapter.setFilterQueryProvider(new FilterQueryProvider() { public Cursor runQuery(CharSequence constraint) { return db.fetchdatabyfilter(constraint.toString(),"name" ); } });
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