如何使 EditText 不为空？

Question

I have an editText and button. EditText is for users' names. I have a problem, my code below.

 String fullname = editText.getText().toString();
    if (TextUtils.isEmpty(fullname)){
        Toast.makeText(this, "Name should not be empty", Toast.LENGTH_SHORT).show();

My problem is when the user clicks on the button without putting anything, toast message show; which is fine but when the user put space it stores fullname value empty. I don't want empty value.

Answer 1

You should trim the input: fullname.trim().isEmpty() to get rid of leading and trailing whitespace. So if you have an input with just whitespace, it will consider it empty.

Answer 2

I would disable the button when the text is invalid. It's better to validate earlier rather than allow an action prematurely. It's also possible, using the TextWatcher to modify the user input to remove invalid spaces etc.

        <EditText
            android:id="@+id/editText"
            android:layout_margin="16dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@android:color/white"/>

        <Button
            android:id="@+id/button"
            android:layout_margin="16dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@android:string/ok"/>

In activity or fragment:

    editText.addTextChangedListener(
            object : TextWatcher {
                override fun afterTextChanged(s: Editable) {
                    button.isEnabled = s.trim().isNotEmpty()
                }

                override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {}

                override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {}

            }
    )