Android Development Series (20): Functions and usage of AutoCompleteTextView (automatically completed text box,

Android Development Series (20): Functions and usage of AutoCompleteTextView (automatically completed text box,

After you enter a certain number of characters, the automatically completed text box displays a drop-down menu for you to choose from. After you select a menu item, AutoCompleteTextView can automatically enter the text box according to your selection.

AutoCompleteTextView is derived from EditText. It has one more function than the normal edit box: after a certain character is entered, the text is automatically completed.

Let's take a look at its attributes:

Android: completionHint: Set the title of the prompt in the drop-down menu

Android: completionHintView: Set the view with the title displayed in the drop-down menu

Android: dropDownHeight: Set the height of the drop-down menu

Android: dropDownHorizontalOffset: sets the horizontal cost between the drop-down menu and the text box. The drop-down menu is left aligned with the text box by default.

Android: dropDownVerticalOffset: sets the vertical offset between the drop-down menu and the text box. The drop-down menu is left aligned with the text box by default.

Android: dropDownWidth: Set the width of the drop-down menu

Android: popupleBackground: Set the background of the drop-down menu

In addition, AutonCompleteTextView derives from a subclass: MultiAutoCompleteTextView, which allows you to enter multiple prompt items. Each prompt item is separated by a separator.

MultiAutoCompleteTextView provides the setTokenizer () method to set separators.

First, create an Android project, and then write the main. xml file:

<Span style = "font-size: 14px;"> <? 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"> <! -- Define an Automatic completion text box, specify a character to enter and prompt --> <AutoCompleteTextView android: hint = "Please fill in your email address" android: id = "@ + id/auto" android: layout_width = "fill_parent" android: layout_height = "wrap_content" android: dropDownHorizontalOffset = "0dp" android: completionThreshold = "1"/> <! -- Define a MultiAutoCompleteTextView component --> <MultiAutoCompleteTextView android: id = "@ + id/mauto" android: layout_width = "fill_parent" android: layout_height = "wrap_content" android: completionThreshold = "1"/> </LinearLayout> </span>

Then, we compile the java code, AutoCompleteTextViewTest. java:

<Span style = "font-size: 14px;"> package org. crazyit. ui; import android. app. activity; import android. OS. bundle; import android. view. view; import android. view. view. onClickListener; import android. widget. arrayAdapter; import android. widget. autoCompleteTextView; import android. widget. button; import android. widget. multiAutoCompleteTextView; import android. widget. textView; public class AutoCompleteTextViewTest extends Activity {AutoCompleteTextView actv; MultiAutoCompleteTextView mauto; // define a String array as the text String of the prompt [] books = new String [] {"Big_AdamApple@qq.com ", "Big_AdamApple@baidu.com", "Big_AdamApple@gmail.com", "Big_AdamApple@sina.com", "Big_AdamApple@163.com", "Big_AdamApple@mail.com", "Big_AdamApple@11.com", };@ Overridepublic void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main); // create an ArrayAdapter that encapsulates the array ArrayAdapter <String> aa = new ArrayAdapter <String> (this, android. r. layout. simple_dropdown_item_1line, books); actv = (AutoCompleteTextView) findViewById (R. id. auto); // set Adapteractv. setAdapter (aa); mauto = (MultiAutoCompleteTextView) findViewById (R. id. mauto); // set Adaptermauto. setAdapter (aa); // set the separator mauto for MultiAutoCompleteTextView. setTokenizer (new MultiAutoCompleteTextView. commaTokenizer () ;}</span>

As follows:

In android: AutoCompleteTextView

Use the following code:
ArrayAdapter <String> adapter = new ArrayAdapter <String> (this,
Android. R. layout. simple_list_item_1, books );

In Android development, AutoCompleteTextView a is automatically completed in the text box. When asetSelectAllOnFocus (true);, a null pointer is thrown?

There is no new object, right? AutoCompleteTextView a = new AutoCompleteTextView (); try