android - 检查 DialogFragment 中的 EditText 值

Question

我正在显示一个 DialogFragment 提示用户提供输入。我想验证此输入(不应为空)并在验证失败时显示 Toast，不关闭对话框。

目前，我在验证失败时显示 Toast，但对话框被关闭。我该如何防止这种情况？

DialogFragment 类:

public class DialogFragmentAddNewFolder extends DialogFragment implements DialogInterface.OnClickListener {

    private EditText etName;
    private DialogFragmentAddNewFolderListener mListener;

    public interface DialogFragmentAddNewFolderListener {
        public void onAddNewFolderPositiveClick(Folder folder);
    }

    @NonNull
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = getActivity().getLayoutInflater();
        View ourView = inflater.inflate(
                R.layout.dialogfragment_add_note, null);
        builder.setView(ourView);
        etName = (EditText) ourView.findViewById(R.id.etAddFolder);

        builder.setTitle(R.string.dialogfragment_add_folder_title);

        builder.setPositiveButton(
                R.string.dialogfragment_add_folder_pos_btn, this);
        builder.setNegativeButton(
                R.string.dialogframent_add_folder_neg_btn, this);
        return builder.create();
    }

    @Override
    public void onClick(DialogInterface dialog, int which) {
        switch (which) {
            case DialogInterface.BUTTON_POSITIVE:
                String name = etName.getText().toString();
                if (name.equals("")) {
                    Toast.makeText(getActivity(), "Provide a name", Toast.LENGTH_SHORT).show();
                } else {
                    Folder folder = new Folder();
                    folder.setName(name);
                    mListener.onAddNewFolderPositiveClick(folder);
                }
                break;

            case DialogInterface.BUTTON_NEGATIVE:
                dialog.dismiss();
                break;
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (DialogFragmentAddNewFolderListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + "Must implement DialogFragmentAddNewFolderListener.");
        }
    }
}

Answer 1

尝试将文本更改监听器应用于您的 EditText 并在该监听器上使用 InputFilter。然后您可以在该过滤器中执行验证逻辑。

在您的情况下，您可能根本不需要该过滤器，您只需在监听器逻辑中进行检查即可。例如

yourEditText.addTextChangedListener(new TextWatcher() {

    @Override
    public void afterTextChanged(Editable s) {

    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        doYourChecking();
    } 

});