1.AutoCompleteTextView，顧名思義即自動補全文本;

public class MainActivity extends AppCompatActivity {    PRivate AutoCompleteTextView autoCompleteTextView;    private ArrayAdapter<String> adapter;    private static final String[] countries ={"China","Russia","USA","India","USA1","USA2","Haha","Xixi","Lala","lala","xixi"};
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);
        autoCompleteTextView = (MultiAutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line,countries);
        autoCompleteTextView.setAdapter(adapter);
    }}
還有布局文件：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context="com.shen.fourth.MainActivity">    <AutoCompleteTextView        android:id="@+id/autoCompleteTextView"        android:layout_width="match_parent"        android:layout_height="wrap_content"        /></LinearLayout>
線性布局里放置一個AutoCompleteTextView；
這樣就可以實現文本的自動補全。
注意：
AutoCompleteTextView的自動補全系統默認是當輸入兩個字符以上時才會自動顯示提示補全文本！
當然也可以自己修改completionThreshold屬性，設置為自定義數值。
2.MultiAutoCompleteTextView,比AutoCompleteTextView加了個Multi就不太一樣了，當然功能也更強大，強大體現在在一次自動補全文本后可以繼續自動補全后邊的文本。
代碼：
public class MainActivity extends AppCompatActivity {    private MultiAutoCompleteTextView multiAutoCompleteTextView;    private ArrayAdapter<String> adapter;    private static final String[] countries ={"China","Russia","USA","India","USA1","USA2","Haha","Xixi","Lala","lala","xixi"};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);
        multiAutoCompleteTextView = (MultiAutoCompleteTextView) findViewById(R.id.multiAutoCompleteTextView);
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line,countries);
        multiAutoCompleteTextView.setAdapter(adapter);
	//此處設置分隔符，這樣當補全一次文本后，后邊的文本也可以自動補全        multiAutoCompleteTextView.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());
    }}
布局文件：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context="com.shen.fourth.MainActivity">    <MultiAutoCompleteTextView        android:id="@+id/multiAutoCompleteTextView"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:completionThreshold="1"/></LinearLayout>與之前相比，此時線性布局里放置的是MultiAutoCompleteTextView;
這里注意到有一個屬性completionThreshold,這個屬性是設置當輸入多少個字符時才會出現提示補全文本的。此處設置為1，數值可以自己定義。
完畢~