Android,Autocomplettextview,强制文本来自条目列表

Question

有没有办法强制autocompletetextview中的条目成为条目列表中的元素之一？

我找到了一个名为"performValidation"的方法,但我不确定它实际上做了什么,而且我还没有找到很多文档或任何示例.

Answer 1

该AutoCompleteTextView有一个称为方法setValidator(),是以界面的一个实例AutoCompleteTextView.Validator作为参数.AutoCompleteTextView.Validator包含isValid()用于检查已输入值的内容,您可以通过实现"修复"此字符串fixText().

似乎这是你能得到的最好的AutoCompleteTextView,作为AutoCompleteTextView.Validator以下状态的文档:

"由于没有万无一失的方法来阻止用户使用不正确的值离开此视图,我们所能做的就是在发生这种情况时尝试自行解决."

如果你的元素列表不是太长,你可能最好使用Spinner.

******编辑:******

我在一起快速举例说明如何使用它,希望它有所帮助!

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<AutoCompleteTextView  
    android:id="@+id/input"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
<EditText
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Focus me to validate above text"/>
</LinearLayout>

-

public class AutoCompleteTextViewActivity extends Activity {

    String[] validWords = new String[]{"", "snowboard", "bobsleigh", "slalom"};

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        AutoCompleteTextView view = (AutoCompleteTextView)findViewById(R.id.input);
        view.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, validWords));
        view.setValidator(new Validator());
        view.setOnFocusChangeListener(new FocusListener());
    }

    class Validator implements AutoCompleteTextView.Validator {

        @Override
        public boolean isValid(CharSequence text) {
            Log.v("Test", "Checking if valid: "+ text);
            Arrays.sort(validWords);
            if (Arrays.binarySearch(validWords, text.toString()) > 0) {
                return true;
            }

            return false;
        }

        @Override
        public CharSequence fixText(CharSequence invalidText) {
            Log.v("Test", "Returning fixed text");

            /* I'm just returning an empty string here, so the field will be blanked,
             * but you could put any kind of action here, like popping up a dialog?
             * 
             * Whatever value you return here must be in the list of valid words.
             */
            return "";
        }
    }

    class FocusListener implements View.OnFocusChangeListener {

        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            Log.v("Test", "Focus changed");
            if (v.getId() == R.id.input && !hasFocus) {
                Log.v("Test", "Performing validation");
                ((AutoCompleteTextView)v).performValidation();
            }
        }
    }
}