郑德才博客

Android开发学习

Android开发中，经常需要使用像百度等搜索引擎上，搜索自动下拉关联

新建布局文件：activity_main.xml，使用AutoCompleteTextView自动关联，下面介绍自动关联成邮箱地址实例，代码内容：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <AutoCompleteTextView

        android:id="@+id/auto_tv"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:layout_gravity="center_horizontal"

        android:layout_marginTop="50dip"

        android:padding="5dip"

        android:hint="请输入您的邮箱"

        android:textSize="16sp" />

</RelativeLayout>

实现的MainActivity.java代码如下：

package com.zhengdecai.autocomplete;

import android.app.Activity;

import android.os.Bundle;

import android.text.Editable;

import android.text.TextWatcher;

import android.widget.AutoCompleteTextView;

/**

 * 自动关联成邮箱地址

 * 

 * @author 郑德才

 *

 */

public class MainActivity extends Activity implements TextWatcher {

private AutoCompleteTextView autoview;

private AutoTextViewAdapter adapter;

private static final String[] AUTO_EMAILS = { "@163.com", "@sina.com",

"@qq.com", "@126.com", "@gmail.com", "@apple.com" };

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

autoview = (AutoCompleteTextView) findViewById(R.id.auto_tv);

adapter = new AutoTextViewAdapter(this);

autoview.setAdapter(adapter);

autoview.setThreshold(1);// 输入1个字符时就开始检测，默认为2个

autoview.addTextChangedListener(this);// 监听autoview的变化

}

@Override

public void afterTextChanged(Editable s) {

// TODO Auto-generated method stub

String input = s.toString();

adapter.mList.clear();

autoAddEmails(input);

adapter.notifyDataSetChanged();

autoview.showDropDown();

}

/**

* 自动填充邮箱列表

* 

* @param input

*/

private void autoAddEmails(String input) {

System.out.println("input-->" + input);

String autoEmail = "";

if (input.length() > 0) {

for (int i = 0; i < AUTO_EMAILS.length; ++i) {

if (input.contains("@")) {// 包含“@”则开始过滤

String filter = input.substring(input.indexOf("@") + 1,

input.length());// 获取过滤器，即根据输入“@”之后的内容过滤出符合条件的邮箱

System.out.println("filter-->" + filter);

if (AUTO_EMAILS[i].contains(filter)) {// 符合过滤条件

autoEmail = input.substring(0, input.indexOf("@"))

+ AUTO_EMAILS[i];// 用户输入“@”之前的内容加上自动填充的内容即为最后的结果

adapter.mList.add(autoEmail);

}

} else {

autoEmail = input + AUTO_EMAILS[i];

adapter.mList.add(autoEmail);

}

}

}

}

@Override

public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,

int arg3) {

// TODO Auto-generated method stub

}

@Override

public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {

// TODO Auto-generated method stub

}

}

使用到的AutoTextViewAdapter显示关联的列表实例：

package com.zhengdecai.autocomplete;

import java.util.ArrayList;

import java.util.List;

import android.content.Context;

import android.graphics.Color;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.Filter;

import android.widget.Filterable;

import android.widget.TextView;

public class AutoTextViewAdapter extends BaseAdapter implements Filterable {

public List<String> mList;

private Context mContext;

private MyFilter mFilter;

public AutoTextViewAdapter(Context context) {

mContext = context;

mList = new ArrayList<String>();

}

@Override

public int getCount() {

return mList == null ? 0 : mList.size();

}

@Override

public Object getItem(int position) {

return mList == null ? null : mList.get(position);

}

@Override

public long getItemId(int position) {

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

if (convertView == null) {

TextView tv = new TextView(mContext);

tv.setTextColor(Color.BLACK);

tv.setTextSize(20);

convertView = tv;

}

TextView txt = (TextView) convertView;

txt.setText(mList.get(position));

return txt;

}

public Filter getFilter() {

if (mFilter == null) {

mFilter = new MyFilter();

}

return mFilter;

}

private class MyFilter extends Filter {

@Override

protected FilterResults performFiltering(CharSequence constraint) {

FilterResults results = new FilterResults();

if (mList == null) {

mList = new ArrayList<String>();

}

results.values = mList;

results.count = mList.size();

return results;

}

@Override

protected void publishResults(CharSequence constraint,

FilterResults results) {

if (results.count > 0) {

notifyDataSetChanged();

} else {

notifyDataSetInvalidated();

}

}

}

}

模拟器运行效果：