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 。