android AutoCompleteTextView自定义的自动补全

1.分析AutoCompleteTextView为什么可以实现自动补全分析源码

if (valueText.startsWith(prefixString)) { newValues.add(value); } else { final String[] words = valueText.split(" "); final int wordCount = words.length; for (int k = 0; k < wordCount; k++) { if (words[k].startsWith(prefixString)) { newValues.add(value); break; } } }

2. 我们反过来再研究一下ArrayAdapter，它除了是BaseAdapter的子类，它还实现了 Filterable 接口！我们在AutoAdapter中，实现该接口，并返回一个自定义的 Filter,所以我们必须实现两个重要的方法： protected FilterResults performFiltering(CharSequence prefix) 在这个方法里面定制过滤策略，根据输入的prefix对数据进行过滤，并组装成FilterResults 结果返回; protected void publishResults(CharSequence constraint, FilterResults results) 这个方法则是发布结果用的，把上面方法的结果按照一定的要求进行处理后，通知Adapter进行数据视图的刷新总结: 按照 AutoCompleteTextView 的工作流程，它依赖两个组件，Adapter 和 Filter，一个是视图的处理，一个是数据过滤处理，对这两个组件进行深度定制，我们就可以随心所欲了。 3.下面是我自己写的自定义AutoCompleteTextView可以按照拼音搜索(就是根据拼音在数据库中查找)

public class MyAutoCompleteTextView1 extends AutoCompleteTextView {private DB4Helper mDb4Helper;public MyAutoCompleteTextView1(Context context){super(context);init(context);}public MyAutoCompleteTextView1(Context context, AttributeSet attrs) {super(context, attrs);init(context);}public void init(final Context context){new Thread(new Runnable() {@Overridepublic void run() {mDb4Helper=DB4Helper.getInstance(context);}}).start();final MyAdapter myAdapter=new MyAdapter(context);setAdapter(myAdapter);addTextChangedListener(new TextWatcher() {@Overridepublic void onTextChanged(CharSequence s, int start, int before, int count) {myAdapter.mList.clear();myAdapter.mList=mDb4Helper.getAddsTableDB(s.toString());myAdapter.notifyDataSetChanged();showDropDown();}@Overridepublic void beforeTextChanged(CharSequence s, int start, int count,int after) {}@Overridepublic void afterTextChanged(Editable s) {}});setThreshold(1);}public class MyAdapter extends BaseAdapter implements Filterable{List<String> mList; private Context mContext; private MyFilter mFilter;public MyAdapter(Context context){this.mContext=context;mList=new ArrayList<String>();}@Overridepublic int getCount() {return mList==null?0:mList.size();}@Overridepublic Object getItem(int position) {return mList==null?null:mList.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {if(convertView==null){TextView tv=(TextView) LayoutInflater.from(mContext).inflate(R.layout.tv,null);tv.setTextColor(Color.BLACK);tv.setTextSize(20);convertView=tv;}TextView tvx=(TextView) convertView;tvx.setText(mList.get(position));return tvx;}@Overridepublic android.widget.Filter getFilter() {if(mFilter==null){mFilter=new MyFilter();}return mFilter;}private class MyFilter extends android.widget.Filter{@Overrideprotected FilterResults performFiltering(CharSequence constraint) {FilterResults results = new FilterResults(); if (mList == null) { mList = new ArrayList<String>(); } results.values = mList; results.count = mList.size(); return results; }@Overrideprotected void publishResults(CharSequence constraint,FilterResults results) {if (results.count > 0) { notifyDataSetChanged(); } else { notifyDataSetInvalidated(); } }}}}

public class DB4Helper extends SQLiteOpenHelper {private final static String tag = "DB4Bank";private static final int DATABASE_VERSION = 1;private static String DB_NAME_DB4 = "tlbank.db";private static DB4Helper mInstance;public static DB4Helper getInstance(Context context) {if(mInstance==null){mInstance=new DB4Helper(context);}return mInstance;}public DB4Helper(Context context){super(context,DB_NAME_DB4,null,DATABASE_VERSION);}public DB4Helper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}@Overridepublic void onCreate(SQLiteDatabase db) {String sql4Adds = "create table AddsTable(m_id integer primary key autoincrement,"+ "adds varchar(255),addspinyin varchar(500),addszimu varchar(255))";db.execSQL(sql4Adds);initAdds(db);}/** * 里面说的数据读者可以自行添加 * @param db */public void initAdds(SQLiteDatabase db){ArrayList<String> list=new ArrayList<String>();for (String sql : list) {db.execSQL(sql);}}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}public ArrayList<String> getAddsTableDB(String guanjianzi) {ArrayList<String> list = new ArrayList<String>();Cursor cursor = null;String sql="select adds from AddsTable where" +" adds like '%"+guanjianzi+"%'or addszimu like '%"+guanjianzi+"%'";cursor=mInstance.getWritableDatabase().rawQuery(sql,null); if(cursor==null){ return list; }while(cursor.moveToNext()){ list.add(cursor.getString(cursor.getColumnIndexOrThrow("adds")));}return list;}}

3.总结AutoCompleteTextView就是PopupWindow 和EditText 加Filterable 进行数据的过滤，也可以自己用EditText加PopupWindow实现一个AutoCompleteTextView ，但是会出现焦点问题，有兴趣的读者可以试试！