1、 private Button queryButton; private Button deleteButton; private Button updateButton; private ListView listView; private EditText nameEditText; private EditText passwordEditText; private TextView tv1; private TextView tv2; private SimpleCursorAdapter adapter; private int currentId; Override protect
2、ed void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DBHelper dbHelper = new DBHelper(this); / 在执行了getWritableDatabase的时候才会创建数据库 db = dbHelper.getWritableDatabase(); insertButton = (Button) findViewById(R.id.insertButton); insertButt
3、on.setOnClickListener(new View.OnClickListener() Override public void onClick(View arg0) insertUserInfo(); ); queryButton = (Button) findViewById(R.id.queryButton); queryButton.setOnClickListener(new View.OnClickListener() public void onClick(View v) queryAllUserInfos(); deleteButton = (Button) find
4、ViewById(R.id.deleteButton); deleteButton.setOnClickListener(new View.OnClickListener() deleteUserInfo(); updateButton = (Button) findViewById(R.id.updateButton); updateButton.setOnClickListener(new View.OnClickListener() updateUserInfo(); listView = (ListView) findViewById(R.id.listView); listView.
5、setOnItemClickListener(new AdapterView.OnItemClickListener() public void onItemClick(AdapterView adapter, View view, int position, long itemId) Cursor cursor = (Cursor) adapter.getItemAtPosition(position); int id = cursor.getInt(cursor.getColumnIndex(_id); String name = cursor.getString(cursor .getC
6、olumnIndex(username String password = cursor.getString(cursorpassword currentId = id; /nameEditText.setText(name); /passwordEditText.setText(password); tv1=(TextView) view.findViewById(R.id.textView1); tv2=(TextView) view.findViewById(R.id.textView2); tv1.setText(name); tv2.setText(password); nameEd
7、itText = (EditText) findViewById(R.id.nameEditText); passwordEditText = (EditText) findViewById(R.id.passwordEditText); public void deleteUserInfo() db.delete(m_userinfo, _id=?, new String String.valueOf(currentId) ); Toast.makeText(this, Delete id + currentId, Toast.LENGTH_SHORT) .show(); public vo
8、id updateUserInfo() String name = nameEditText.getText().toString(); String password = passwordEditText.getText().toString(); ContentValues contentValues = new ContentValues(); contentValues.put(, name);, password); db.update(, contentValues, Update id public void insertUserInfo() / 设置数据库的null数值 / c
9、ontentValues.putNull(); / 如果我们不添加nullColumnHack的话,那么我们的sql语句最终的结果将会类似insert into / tableName()values(); / 这显然是不允许的。而如果我们添加上nullColumnHack呢, / sql将会变成这样,insert into tableName / (nullColumnHack)values(null);这样很显然就是可以的。 long rowId = db.insert(, null, contentValues);insert rowId + rowId, Toast.LENGTH_SH
10、ORT) nameEditText.setText(null); passwordEditText.setText(null); currentId = -1; public void queryAllUserInfos() / columns如果是null,则返回所有的列 Cursor cursor = db.query(, null, null, null, null, null, null); / 按username排序 / Cursor cursor = db.query( / / 加搜索条件, null, username like ?, new / String%p%, null,
11、 null, Log.d(TAG, Cursor + cursor); / adapter = new SimpleCursorAdapter(this, / android.R.layout.simple_list_item_2, cursor, new String / , new int / android.R.id.text1, android.R.id.text2 ); adapter = new SimpleCursorAdapter(this, R.layout.sss, cursor, new String R.id.textView1, R.id.textView2 ); l
12、istView.setAdapter(adapter); / while (cursor.moveToNext() / int id = cursor.getInt(0); / String username = cursor.getString(1); String username = cursor.getString(cursor .getColumnIndex( String password = cursor.getString(cursor Log.d(TAG, id + id + , username + username + , password + password); pr
13、otected void onDestroy() db.close(); super.onDestroy();Sqlhelp:import android.content.Context;import android.database.sqlite.SQLiteCursorDriver;import android.database.sqlite.SQLiteQuery;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;publi
14、c class DBHelper extends SQLiteOpenHelper public static final String TAG = public static final String DB_NAME = mydb.dbpublic static final int VERSION = 1;public DBHelper(Context context) /super(context, DB_NAME, null, VERSION);super(context, DB_NAME, null, VERSION);Overridepublic void onCreate(SQLi
15、teDatabase db) Log.d(TAG, Database on createString sql = CREATE TABLE m_userinfo(_id INTEGER PRIMARY KEY AUTOINCREMENT, username VARCHAR(256), password VARCHAR(256)db.execSQL(sql);public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)Database on upgrade old version + oldVersion + , new version + newVersion);Xml: +id/passwordEditText/LinearLayoutButton+id/insertButtontext=Insert /+id/queryButtonQuery+id/deleteButtonDelete+id/updateButtonUpdateListView+id/listView/ListView
copyright@ 2008-2022 冰豆网网站版权所有
经营许可证编号:鄂ICP备2022015515号-1