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我试图从MSSQL数据库中将数据数据提取到微调器中,但我无法这样做。我得到这个例外: Exception due to Array adapter or 'Method invocation spnVnames.setAdapter(NoCoreAdapter) may produce java.lang.NullPointerException'
请帮我找到我在下面的代码中的错误。阵列适配器<String >错误
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
currentDate = (TextView) findViewById(R.id.currentDate);
long date = System.currentTimeMillis();
SimpleDateFormat sdf = new SimpleDateFormat(" dd/MM/ yyyy");
String dateString = sdf.format(date);
currentDate.setText(dateString);
Spinner spnVnames = (Spinner) findViewById(R.id.spinner);
String query = " SELECT TaxName FROM tblTax "; //select query
try {
Connection con = connectionClass.CONN();
Statement stmt = con.prepareStatement(query);
ResultSet rs = stmt.executeQuery(query);
List <String> data = new ArrayList < >();
while (rs.next()) {
String id = rs.getString("TaxName");
data.add(id);
}
String[] array = data.toArray(new String[data.size()]);
ArrayAdapter <String> NoCoreAdapter = new ArrayAdapter < > (MainActivity.this, android.R.layout.simple_list_item_1, array);
spnVnames.setAdapter(NoCoreAdapter);
} catch (SQLException e) {
e.printStackTrace();
}
}
的 “...可能会产生显示java.lang.NullPointerException” 的事情只是一个警告。如果您在运行时实际得到'Exception',则需要发布堆栈跟踪。 –
致命例外:主进程:com.example.aits.cherrysales,PID:23161 java.lang.RuntimeException:无法启动活动ComponentInfo {com.example.aits.cherrysales/com.example.aits.cherrysales.MainActi vity} :java.lang.NullPointerException ---这是例外情况... hw继续? –
格式。添加标签。改进拼写 – Patrick2607