我正在编写一个应用程序,其中如果存在于 SQLite 数据库表中,我需要获取第一行数据,我已经编写了将数据存储到数据库中的代码,但现在我想从数据库中获取第一行数据到 TextView 中。
助手类:-
// Select Data
public String[] SelectData(String strOperatorID) {
// TODO Auto-generated method stub
try {
String arrData[] = null;
SQLiteDatabase db;
db = this.getReadableDatabase(); // Read Data
Cursor cursor = db.query(TABLE_NAME, new String[] { "*" },
"OperatorID=?",
new String[] { String.valueOf(strOperatorID) }, null, null, null, null);
if(cursor != null)
{
if (cursor.moveToFirst()) {
arrData = new String[cursor.getColumnCount()];
arrData[0] = cursor.getString(0); // DeviceID
arrData[1] = cursor.getString(1); // EmailID
arrData[2] = cursor.getString(2); // Event
arrData[3] = cursor.getString(3); // Operator
arrData[4] = cursor.getString(4); // EventOperator
}
}
cursor.close();
db.close();
return arrData;
} catch (Exception e) {
return null;
}
}
正如你所看到的,我已经编写了基于 OperatorID=? 来获取数据的代码。但现在我只需要将第一行数据获取到文本视图中。
因此,让我知道我需要在上面的代码中提交哪些更改,以获取第一行数据(如果存在),否则 toast 不存在。
登录活动.java:
// Save Data
long saveStatus = myDb.InsertData(
txtDeviceID.getText().toString(),
txtEmailID.getText().toString(),
txtEvent.getText().toString(),
txtOperative.getText().toString(),
txtEventOperator.getText().toString()
);
使用上面的代码我将数据存储到数据库中,并且以同样的方式我想从数据库获取数据并希望在用户访问 LoginActivity.java 时显示,无论正确关闭应用程序后...
更新:-
public class LoginActivity extends Activity {
.................
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
setContentView(R.layout.activity_login);
btnLogout = (Button) findViewById(R.id.btnLogout);
btnCamera = (Button) findViewById(R.id.btnCamera);
btnGallery = (Button) findViewById(R.id.btnGallery);
txtDeviceID = (TextView) findViewById(R.id.txtDeviceID);
txtEmailID = (TextView) findViewById(R.id.txtEmailID);
txtEvent = (TextView) findViewById(R.id.txtEvent);
txtOperative = (TextView) findViewById(R.id.txtOperative);
txtEventOperator = (TextView) findViewById(R.id.txtEventOperator);
Intent intent = getIntent();
deviceID = intent.getStringExtra("deviceID");
emailID = intent.getStringExtra("emailID");
event = intent.getStringExtra("name");
operative = intent.getStringExtra("firstName");
txtDeviceID.setText(deviceID);
txtEmailID.setText(emailID);
txtEvent.setText(event);
txtOperative.setText(operative);
txtEventOperator.setText(event + " " + operative);
strEvent = txtEvent.getText().toString();
strOperative = txtOperative.getText().toString();
// Dialog
final AlertDialog.Builder adb = new AlertDialog.Builder(this);
AlertDialog ad = adb.create();
// new Class DB
final myDBClass myDb = new myDBClass(this);
// Save Data
long saveStatus = myDb.InsertData(
txtDeviceID.getText().toString(),
txtEmailID.getText().toString(),
txtEvent.getText().toString(),
txtOperative.getText().toString(),
txtEventOperator.getText().toString()
);
if(saveStatus <= 0)
{
ad.setMessage("Error!! ");
ad.show();
return;
}
// Show Data
String arrData[] = myDb.SelectData();
if(arrData != null)
{
txtDeviceID.setText(arrData[1]);
txtEmailID.setText(arrData[2]);
txtEvent.setText(arrData[3]);
txtOperative.setText(arrData[4]);
txtEventOperator.setText(arrData[5]);
}
if(txtEvent.getText().toString().equals("") && txtOperative.getText().toString().equals(""))
{
Intent intentCall = new Intent(LoginActivity.this, LicenseListActivity.class);
startActivity(intentCall);
}
}