一步一步学android控件（之六） —— MultiAutoCompleteTextView
今天学习的控件是MultiAutoCompleteTextView 。 提到MultiAutoCompleteTextView 我们就自然而然地想到AutoCompleteTextView ，就想知道他们之间到底有什么区别。在讲他们区别之前呢先来看看下面两张图片：
（图1）AutoCompleteTextView （图2）MultiAutoCompleteTextView
这两张图片中使用的都是同样的Adapter ， 然而在图1中输入图2中的内容时却得不到任何内容，为什么？
先从他们的关系上说说， MultiAutoCompleteTextView 继承自AutoCompleteTextView（废话 ... 囧） ， 在使用上多了一个Tokenizer —— 在图2中，这个Tokenizer就是符号 ‘ , ’ ，当遇到这个符号时会根据光标的位置计算当前关注的信息。如：如果光标在 d 的位置，则 ‘ , ’之前的字串有效；如果光标在 g 位置，则 ‘ , ’ 后面的字串有效；另外如果光标前后都有符号‘ , ’ ， 则在两个 ‘ , ’ 中的内容有效。对于这段解释，下面的代码获取更具说服力：
public static class SelfDedineTokenizer implements Tokenizer {
private char mTokenizer = ',';
public SelfDedineTokenizer() {
}
public SelfDedineTokenizer(char token) {
mTokenizer = token;
}
public int findTokenEnd(CharSequence text, int cursor) {
int i = cursor;
int len = text.length();
while (i < len) {
if (text.charAt(i) == mTokenizer) {
return i;
} else {
i++;
}
}
return len;
}
public int findTokenStart(CharSequence text, int cursor) {
int i = cursor;
while (i > 0 && text.charAt(i - 1) != mTokenizer) {
i--;
}
while (i < cursor && text.charAt(i) == ' ') {
i++;
}
return i;
}
public CharSequence terminateToken(CharSequence text) {
int i = text.length();
while (i > 0 && text.charAt(i - 1) == ' ') {
i--;
}
if (i > 0 && text.charAt(i - 1) == mTokenizer) {
return text;
} else {
if (text instanceof Spanned) {
SpannableString sp = new SpannableString(text
+ String.valueOf(mTokenizer));
TextUtils.copySpansFrom((Spanned) text, 0, text.length(),
Object.class, sp, 0);
return sp;
} else {
return text + String.valueOf(mTokenizer);
}
}
}
public void setToken(char token) {
mTokenizer = token;
}
public char getToken() {
return mTokenizer;
}
}
这段代码是自定义的Tokenizer ， 默认使用 ‘ , ’ 作为分隔符， 若想用其他的符号替换 ‘ , ’ 使用setToken方法即可。
废话也说了那么多了，现在说说今天要做的事情
1、使用异步调用方法（Executors）加载MultiAutoCompleteTextView 中 Adapter 需要的数据（数据跟AutoCompleteTextView一样，有疑问的可参见 点击一步一步学android控件（之五） —— AutoCompleteTextView）
2、在MultiAutoCompleteTextView中使用自定义的Tokenizer而不是默认的Tokenizer。
下面就来实现这些功能，老规矩先准备资源文件
1、 创建布局文件 multi_auto_complete_textview.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<MultiAutoCompleteTextView
android:id="@+id/show_multi_complete"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:layout_marginTop="20dp" />
</LinearLayout>
2、创建activity ——WidgetMultiAutoCompleteActivity.java
package com.xy.zt.selfdefinewieget;
import java.io.File;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.TextUtils;
import android.widget.ArrayAdapter;
import android.widget.MultiAutoCompleteTextView;
import android.widget.MultiAutoCompleteTextView.Tokenizer;
public class WidgetMultiAutoCompleteActivity extends Activity {
public static final String[] DEFAULT_DATAS = new String[] { "China",
"chengdu", "xueyu", "ting", "baba", "mama", "meimei" };
public static final int MSG_RECEIVE_TASK_DATA = 1024;
private ExecutorService mExecutor;
private ArrayAdapter<String> mMultiAdapter;
private MultiAutoCompleteTextView mShowMulti;
// private CommaTokenizer mComma = new CommaTokenizer();
private Future<List<String>> mListFileTask;
private static final Callable<List<String>> LIST_FILES = new Callable<List<String>>() {
public List<String> call() throws Exception {
File rootDir = Environment.getRootDirectory();
LinkedList<File> queue = new LinkedList<File>();
ArrayList<String> result = new ArrayList<String>(100);
queue.offer(rootDir);
File tmpFile, tmpDirAllFile[];
while ((tmpFile = queue.poll()) != null) {
if (tmpFile.isDirectory()) {
tmpDirAllFile = tmpFile.listFiles();
if (tmpDirAllFile != null) {
for (File f : tmpDirAllFile) {
queue.offer(f);
}
}
} else {
result.add(tmpFile.getName());
}
}
return result;
}
};
Handler mHandler = new Handler() {
@SuppressWarnings("unchecked")
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_RECEIVE_TASK_DATA:
List<String> datas;
try {
datas = (List<String>) msg.obj;
} catch (ClassCastException e) {
datas = useDefaultData();
}
mShowMulti.setEnabled(true);
mMultiAdapter = new ArrayAdapter<String>(
WidgetMultiAutoCompleteActivity.this,
R.layout.auto_complete_item, R.id.auto_item_file_name,
datas);
mShowMulti.setAdapter(mMultiAdapter);
break;
}
;
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.multi_auto_complete_textview);
init();
mExecutor = Executors.newCachedThreadPool();
mListFileTask = mExecutor.submit(LIST_FILES);
mExecutor.submit(new Runnable() {
@SuppressLint("HandlerLeak")
public void run() {
List<String> datas;
try {
datas = mListFileTask.get();
} catch (InterruptedException e) {
datas = useDefaultData();
} catch (ExecutionException e) {
datas = useDefaultData();
}
Message msg = mHandler.obtainMessage(MSG_RECEIVE_TASK_DATA);
msg.obj = datas;
mHandler.sendMessage(msg);
}
});
}
void init() {
mShowMulti = (MultiAutoCompleteTextView) findViewById(R.id.show_multi_complete);
mShowMulti.setEnabled(false);
mShowMulti.setTokenizer(mCustomerToken);
mShowMulti.setThreshold(1);
}
private List<String> useDefaultData() {
List<String> datas = new ArrayList<String>();
for (String s : DEFAULT_DATAS) {
datas.add(s);
}
return datas;
}
@Override
protected void onDestroy() {
super.onDestroy();
mExecutor.shutdown();
}
SelfDedineTokenizer mCustomerToken = new SelfDedineTokenizer(';');
public static class SelfDedineTokenizer implements Tokenizer {
private char mTokenizer = ',';
public SelfDedineTokenizer() {
}
public SelfDedineTokenizer(char token) {
mTokenizer = token;
}
public int findTokenEnd(CharSequence text, int cursor) {
int i = cursor;
int len = text.length();
while (i < len) {
if (text.charAt(i) == mTokenizer) {
return i;
} else {
i++;
}
}
return len;
}
public int findTokenStart(CharSequence text, int cursor) {
int i = cursor;
while (i > 0 && text.charAt(i - 1) != mTokenizer) {
i--;
}
while (i < cursor && text.charAt(i) == ' ') {
i++;
}
return i;
}
public CharSequence terminateToken(CharSequence text) {
int i = text.length();
while (i > 0 && text.charAt(i - 1) == ' ') {
i--;
}
if (i > 0 && text.charAt(i - 1) == mTokenizer) {
return text;
} else {
if (text instanceof Spanned) {
SpannableString sp = new SpannableString(text
+ String.valueOf(mTokenizer));
TextUtils.copySpansFrom((Spanned) text, 0, text.length(),
Object.class, sp, 0);
return sp;
} else {
return text + String.valueOf(mTokenizer);
}
}
}
public void setToken(char token) {
mTokenizer = token;
}
public char getToken() {
return mTokenizer;
}
}
}
今天主要的内容就在这个文件中，先来看看
private static final Callable<List<String>> LIST_FILES = new Callable<List<String>>()
Callable接口类似于Runnable，只是他是有返回结果的Runnable ， 在他的call方法中做搜索系统文件的工作。 在onCreat函数中有下面代码：
mExecutor = Executors.newCachedThreadPool();
mListFileTask = mExecutor.submit(LIST_FILES);
这段代码第一句创建了一个线程池，第二句将ListFILES提交到线程池进行处理。接下来的代码：
mExecutor.submit(new Runnable() {
@SuppressLint("HandlerLeak")
public void run() {
List<String> datas;
try {
datas = mListFileTask.get();
} catch (InterruptedException e) {
datas = useDefaultData();
} catch (ExecutionException e) {
datas = useDefaultData();
}
Message msg = mHandler.obtainMessage(MSG_RECEIVE_TASK_DATA);
msg.obj = datas;
mHandler.sendMessage(msg);
}
});
这段代码将一个Runnable提交到线程池执行，mListFileTask.get(); 这句在Callable中的call函数没有执行完之前一直处于阻塞状态（不可以放到主线程中），得到数据后发送消息更新UI。
在init函数中有这么一句：
mShowMulti.setTokenizer(mCustomerToken);
表示使用的是自定义的Tokenizer，他的定义如下
SelfDedineTokenizer mCustomerToken = new SelfDedineTokenizer(';');
这样看到的效果跟图二的就有点不同了哦 ^_^......
3、 完善真个工程，下面滴内容也是不可少滴。也写了几个控件了，看看现在ViewData.java中的内容
package com.xy.zt.selfdefinewieget.data;
import java.util.ArrayList;
final public class ViewData {
public final static ArrayList<ViewData> View_Datas = new ArrayList<ViewData>();
public static final int TEXT_VIEW_ID = 90000;
public static final String TEXT_VIEW_NAME = "TextView";
public static final int BUTTON_ID = TEXT_VIEW_ID + 1;
public static final String BUTTON_NAME = "Button";
public static final int EDIT_TEXT_ID = BUTTON_ID + 1;
public static final String EDIT_TEXT_NAME = "EditText";
public static final int AUTO_COMPLETE_TEXTVIEW_ID = EDIT_TEXT_ID + 1;
public static final String AUTO_COMPLETE_TEXTVIEW_NAME = "AutoCompleteTextView";
public static final int MULTI_AUTO_COMPLETE_TEXTVIEW_ID = AUTO_COMPLETE_TEXTVIEW_ID + 1;
public static final String MULTI_AUTO_COMPLETE_TEXTVIEW_NAME = "MultiAutoCompleteTextView";
private static final ViewData mTextView = new ViewData(TEXT_VIEW_NAME,
TEXT_VIEW_ID);
private static final ViewData mButton = new ViewData(BUTTON_NAME, BUTTON_ID);
private static final ViewData mEditText = new ViewData(EDIT_TEXT_NAME,
EDIT_TEXT_ID);
private static final ViewData mAutoCompleteTextView = new ViewData(
AUTO_COMPLETE_TEXTVIEW_NAME, AUTO_COMPLETE_TEXTVIEW_ID);
private static final ViewData mMultiAutoCompleteTextView = new ViewData(
MULTI_AUTO_COMPLETE_TEXTVIEW_NAME, MULTI_AUTO_COMPLETE_TEXTVIEW_ID);
public final String mViewName;
public final int mViewId;
private ViewData(String name, int id) {
mViewName = name;
mViewId = id;
}
static {
View_Datas.add(mTextView);
View_Datas.add(mButton);
View_Datas.add(mEditText);
View_Datas.add(mAutoCompleteTextView);
View_Datas.add(mMultiAutoCompleteTextView);
}
}
最后在WidgetsAdapter的handleItemClicked函数中加入如下内容：
case ViewData.MULTI_AUTO_COMPLETE_TEXTVIEW_ID:
intent.setClass(mContext, WidgetMultiAutoCompleteActivity.class);
mContext.startActivity(intent);
break;
handleItemClicked 最新内容如下：
private void handleItemClicked(int action) {
Intent intent = new Intent();
switch (action) {
case ViewData.TEXT_VIEW_ID:
intent.setClass(mContext, WidgetTextView.class);
mContext.startActivity(intent);
break;
case ViewData.BUTTON_ID:
intent.setClass(mContext, WidgetButtonActivity.class);
mContext.startActivity(intent);
break;
case ViewData.EDIT_TEXT_ID:
intent.setClass(mContext, WidgetEditTextActivity.class);
mContext.startActivity(intent);
break;
case ViewData.AUTO_COMPLETE_TEXTVIEW_ID:
intent.setClass(mContext, WidgetAutoCompleteActivity.class);
mContext.startActivity(intent);
break;
case ViewData.MULTI_AUTO_COMPLETE_TEXTVIEW_ID:
intent.setClass(mContext, WidgetMultiAutoCompleteActivity.class);
mContext.startActivity(intent);
break;
}
}
MultiAutoCompleteTextView 就介绍到这里了，下一个控件 Toast 。
