Question

嘿，我正在尝试使用EditText中的值填充新对话框中的ListView。问题是我得到了

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(java.lang.CharSequence)' on a null object

我对从ListView获得的值进行Toast并且它有效，它返回特定值。当我尝试拨打.setText(ValueFromListView)时，它会出错并且我不明白为什么。谁能帮我这个？这是代码：

@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, final long id) {
    final Dialog dialog = new Dialog(MainActivity.this);
    dialog.setTitle("Edit item...");
    dialog.setContentView(R.layout.custom_dialog_edit_delete);
    dialog.show();

    Button button_UPDATE = (Button) dialog.findViewById(R.id.custom_dialog_edit_delete_button_UPDATE);
    Button button_CANCEL = (Button) dialog.findViewById(R.id.custom_dialog_edit_delete_button_CANCEL);
    Button button_DELETE = (Button) dialog.findViewById(R.id.custom_dialog_edit_delete_button_DELETE);

    // GET PRODUCT REFERENCES
    Cursor cursor = (Cursor) parent.getItemAtPosition(position);
    String productName = cursor.getString(cursor.getColumnIndex(DBAdapter.KEY_PRODUCT));
    String productPrice = cursor.getString(cursor.getColumnIndex(DBAdapter.KEY_PRICE));
    String productType = cursor.getString(cursor.getColumnIndex(DBAdapter.KEY_TYPE));
    Toast.makeText(MainActivity.this, productName + " " + productPrice + " " + productType, Toast.LENGTH_SHORT).show(); 

    EditText prodField = (EditText) findViewById(R.id.custom_dialog_edit_delete__productName);
    prodField.setText(productName); // This is the line that i get the null pointer exception
}

Answer 1

对话框中有

EditText，因此在创建EditText对象时必须提供yout对话框的参考。

EditText prodField = (EditText) dialog.findViewById(R.id.custom_dialog_edit_delete__productName);

Answer 2

试试这个

EditText prodField = (EditText)dialog.findViewById(R.id.custom_dialog_edit_delete__productName);
prodField.setText(productName);

//

使用ListView

2 个答案: