使用TextWatcher監聽EditText

通訊錄搜索功能，每輸入一個字符，就會監聽有所變化，這用到了TextWatcher監聽EditText

this.search_content = (EditText) findViewById(R.id.search_content);
search_content.addTextChangedListener(new TextFilter());

TextFilter如下：

class TextFilter implements TextWatcher {
		@Override
		public void afterTextChanged(Editable s) {
			// TODO Auto-generated method stub
		}
		@Override
		public void beforeTextChanged(CharSequence s, int start, int count,
				int after) {
			// TODO Auto-generated method stub
		}
		@Override
		public void onTextChanged(CharSequence s, int start, int before,
				int count) {
			searchContent = search_content.getText().toString();
			// 從數據庫中獲得查詢的聯繫人
			contactDao = new ContactDao(getApplicationContext());
			String Sql = "select * from contact_usr where username like '%"
					+ searchContent + "%'";
			String message = contactDao.execQuery(Sql);
			search_userdata = getUserData(message);

			// 爲聯繫人創建listitem適配器
			SimpleAdapter adapter = new MyAdapter(SearchUserActivity.this,
					search_userdata, R.layout.userlist_item_layout,
					new String[] { "user_photo", "user_name", "user_tel",
							"user_store" }, new int[] { R.id.user_phote,
							R.id.user_name, R.id.user_tel, R.id.store_user });
			// 將listitem綁定到適配器上
			search_user_list.setAdapter(adapter);

		}

	}