Android: Restrict user from selecting other than autocompletion suggestions?

问题

I have provided an AutoCompleteTextView to show suggestions to the user. Based on the item selected by the user, I am getting the ID of the item and using it in data base side. Now my problem is to force the user to make selection only from AutoCompleteTextView (i.e. user should not enter his own text). It is a client requirement. How to do this?

回答1:

Here's a pretty straightforward solution:

You can create a variable to store the selected value by setting setOnItemClickListener in your AutoCompleteTextView. Then you can null that value whenever a user types in the field by adding a TextWatcher to it. Finally, you can validate your variable is not null before continuing.

String my_var; //keep track!
AutoCompleteTextView tv = (AutoCompleteTextView) layout.findViewById(R.id.tv);
tv.setAdapter(my_adapter);  
tv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        my_var = my_adapter.getItem(position).toString();
    }
});
/**
 * Unset the var whenever the user types. Validation will
 * then fail. This is how we enforce selecting from the list.
 */
tv.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        my_var = null;
    }
    @Override
    public void afterTextChanged(Editable s) {}
});

回答2:

I happened to need such a requirement for a project I am working on, and I though I'll share you guys the way I implemented the required.

I added a on focus change listener for the auto-complete text view and checked when the user has focus changed focus from the auto-complete, and handled the situation straight forward.

autoTextViewCountry.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View view, boolean b) {
            if(!b) {
                // on focus off
                String str = autoTextViewCountry.getText().toString();

                ListAdapter listAdapter = autoTextViewCountry.getAdapter();
                for(int i = 0; i < listAdapter.getCount(); i++) {
                    String temp = listAdapter.getItem(i).toString();
                    if(str.compareTo(temp) == 0) {
                        return;
                    }
                }

                autoTextViewCountry.setText("");

            }
        }
    });

So my implementation is: if the typed text doesn't exist in the array adapter then on focus changed empty the text view, and later on when continuing to next stage of say registration, check if this text view is empty or not.

Hope this approach helps somebody.

Happy coding.

回答3:

NiceAutoCompleteTextView will give you the ability to check whether a selection was made from the drop-down popup, by invoking isSelectionFromPopup()

回答4:

Ok I assume you would like to limit the input of the user to the texts contained in the list of items listed in the suggest box.

For instance if you have:

One
Two
Three

then the user could only type for the first character "O" and "T". And so on according to the text entered before.

To achieve this you can utilize the setFilters method of TextView:

editBox = (TextView) findViewById(R.id.editBox);
editBox.setFilters(getFilters());
editBox.addTextChangedListener(this);
editBox.setOnFocusChangeListener(this);

Additionally you would probably need the text change listener and focus listener to react and update the filtered list when a new character is entered ... plus to update the filter.

Here is an example of decimal number filter I have used on a project:

protected InputFilter[] getFilters()
    {
        InputFilter[] filters = new InputFilter[1];

        filters[0] = new InputFilter()
        {
            public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend)
            {
                // limit input to digits and decimal / thousand separator only
                // in case thousand separator is pressed, change it to decimal
                // separator instead
                String output = "";

                if (number.isFocused())
                {
                    for (int i = start; i < end; i++)
                    {
                        char c = source.charAt(i);

                        if (isDecimalOrThousandSeparator(c))
                        {
                            output = output + Character.toString(decimalSeparator);
                        }
                        else if (Character.isDigit(c))
                        {
                            output = output + Character.toString(c);
                        }
                    }

                    return output == "" ? null : output;
                }

                return null;
            }
        };

        return filters;
    }

来源：https://stackoverflow.com/questions/13394054/android-restrict-user-from-selecting-other-than-autocompletion-suggestions

标签

android

autocompletetextview