AutoCompleteTextView搜索框显示记录的实现

直接上代码：

xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"  
    >  
    <!--  当之有一个EditText或者AutoCompleteTextView的时候，进入画面时是默认得到焦点的。  
          要想去除焦点，可以在auto之前加一个o像素的layout，并设置他先得到焦点。 -->  
    <LinearLayout android:layout_width="0px"    
        android:layout_height="0px" android:focusable="true"    
        android:focusableInTouchMode="true"></LinearLayout>    
      
    <!-- 定义一个自动完成文本框，指定输入一个字符后进行提示 -->  
    <AutoCompleteTextView    
        android:id="@+id/auto"  
        android:layout_width="fill_parent"   
        android:layout_height="wrap_content"   
        android:hint="请输入文字进行搜索"  
        android:completionHint="最近的5条记录"  
        android:dropDownHorizontalOffset="20dp"  
        android:completionThreshold="1"  
        android:dropDownHeight="fill_parent"/>  
          
        <!--   
        android:completionHint            设置出现在下拉菜单中的提示标题  
        android:completionThreshold       设置用户至少输入多少个字符才会显示提示  
        android:dropDownHorizontalOffset  设置下拉菜单于文本框之间的水平偏移。下拉菜单默认与文本框左对齐  
        android:dropDownVerticalOffset    设置下拉菜单于文本框之间的垂直偏移。下拉菜单默认紧跟文本框  
        android:dropDownHeight               设置下拉菜单的高度  
        android:dropDownWidth                设置下拉菜单的宽度  
        -->  
     <Button android:text="搜索" android:id="@+id/search"    
        android:layout_width="wrap_content"    
        android:layout_height="wrap_content"/>     
</LinearLayout>  

 

activity:

public class MainActivity extends Activity {  
  
    private AutoCompleteTextView autoCompleteTextView;  
  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
  
        autoCompleteTextView = (AutoCompleteTextView) findViewById(R.id.auto);  
        initAutoComplete("history", autoCompleteTextView);  
        Button searchButton = (Button) findViewById(R.id.search);  
        searchButton.setOnClickListener(new MyOnClickListener());  
    }  
  
    private final class MyOnClickListener implements OnClickListener {  
        @Override  
        public void onClick(View v) {  
            saveHistory("history", autoCompleteTextView);  
        }  
    }  
  
    /** 
     * 把指定AutoCompleteTextView中内容保存到sharedPreference中指定的字符段 
     *  
     * @param field 
     *            保存在sharedPreference中的字段名 
     * @param autoCompleteTextView 
     *            要操作的AutoCompleteTextView 
     */  
    private void saveHistory(String field,  AutoCompleteTextView autoCompleteTextView) {  
        String text = autoCompleteTextView.getText().toString();  
        SharedPreferences sp = getSharedPreferences("network_url", 0);  
        String longhistory = sp.getString(field, "nothing");  //从SharedPreferences中读取history，如果没有，就返回nothing
        if (!longhistory.contains(text + ",")) {                //判断当前的记录是否已经存在
            StringBuilder sb = new StringBuilder(longhistory);  
            sb.insert(0, text + ",");  
            //创建SharedPreferences编辑器
            SharedPreferences.Editor editor = sp.edit();
            editor.putString("history", sb.toString());
            editor.commit();  
        }   
    }  
  
    /** 
     * 初始化AutoCompleteTextView，最多显示5项提示，使 AutoCompleteTextView在一开始获得焦点时自动提示 
     *  
     * @param field 
     *            保存在sharedPreference中的字段名 
     * @param autoCompleteTextView 
     *            要操作的AutoCompleteTextView 
     */  
    private void initAutoComplete(String field,  
            AutoCompleteTextView autoCompleteTextView) {  
        SharedPreferences sp = getSharedPreferences("network_url", 0);  
        String longhistory = sp.getString("history", "nothing");  
        String[] histories = longhistory.split(",");  
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,  
                android.R.layout.simple_dropdown_item_1line, histories);  
        // 只保留最近的50条的记录  
        if (histories.length > 50) {  
            String[] newHistories = new String[50];  
            System.arraycopy(histories, 0, newHistories, 0, 50);  
            adapter = new ArrayAdapter<String>(this,  
                    android.R.layout.simple_dropdown_item_1line, newHistories);  
        }  
        autoCompleteTextView.setAdapter(adapter);  
        autoCompleteTextView  
                .setOnFocusChangeListener(new OnFocusChangeListener() {  
                    @Override  
                    public void onFocusChange(View v, boolean hasFocus) {  
                        AutoCompleteTextView view = (AutoCompleteTextView) v;  
                        if (hasFocus) {  
                            view.showDropDown();  
                        }  
                    }  
                });  
    };
}