/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.widget;
import android.content.Context;
import android.text.Editable;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.TextUtils;
import android.text.method.QwertyKeyListener;
import android.util.AttributeSet;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
/**
* 一个继承自 {@link AutoCompleteTextView} 的可编辑的文本视图，
* 能够根据用户的输入进行自动完成提示，而不需要用户输入整个内容.
* <p>
* 你必须提供 {@link Tokenizer} 用于查找不同的子串.
*
* <p>下面的代码片段展示了，如何创建根据用户输入的国家名称进行完成提示的文本视图：</p>
* <pre class="prettyprint">
* public class CountriesActivity extends Activity {
* protected void onCreate(Bundle savedInstanceState) {
* super.onCreate(savedInstanceState);
* setContentView(R.layout.autocomplete_7);
*
* ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
* android.R.layout.simple_dropdown_item_1line, COUNTRIES);
* MultiAutoCompleteTextView textView = (MultiAutoCompleteTextView) findViewById(R.id.edit);
* textView.setAdapter(adapter);
* textView.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());
* }
*
* private static final String[] COUNTRIES = new String[] {
* "比利时", "法国", "意大利", "德国", "西班牙"
* };
* }</pre>
* @author translate by 颖哥儿
* @author translate by cnmahj
* @author convert by cnmahj
*/
public class MultiAutoCompleteTextView extends AutoCompleteTextView {
private Tokenizer mTokenizer;
public MultiAutoCompleteTextView(Context context) {
this(context, null);
}
public MultiAutoCompleteTextView(Context context, AttributeSet attrs) {
this(context, attrs, com.android.internal.R.attr.autoCompleteTextViewStyle);
}
public MultiAutoCompleteTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
/* package */ void finishInit() { }
/**
* 设置用于根据用户输入的文本确定相关范围的分解器.
*/
public void setTokenizer(Tokenizer t) {
mTokenizer = t;
}
/**
* 该方法不筛选编辑框中的所有内容，只筛选 {@link Tokenizer#findTokenStart}
* 到 {@link #getSelectionEnd} 的长度大于等于 {@link #getThreshold} 的内容.
*/
@Override
protected void performFiltering(CharSequence text, int keyCode) {
if (enoughToFilter()) {
int end = getSelectionEnd();
int start = mTokenizer.findTokenStart(text, end);
performFiltering(text, start, end, keyCode);
} else {
dismissDropDown();
Filter f = getFilter();
if (f != null) {
f.filter(null);
}
}
}
/**
* 该方法不根据编辑框中的文本长度来判断，而是根据 {@link Tokenizer#findTokenStart}
* 到 {@link #getSelectionEnd} 的长度是否大于等于 {@link #getThreshold} 来判断.
*/
@Override
public boolean enoughToFilter() {
Editable text = getText();
int end = getSelectionEnd();
if (end < 0 || mTokenizer == null) {
return false;
}
int start = mTokenizer.findTokenStart(text, end);
if (end - start >= getThreshold()) {
return true;
} else {
return false;
}
}
/**
* 该方法不验证编辑框中的整个文本，而是逐个验证文本标记.空标记将被移除.
*/
@Override
public void performValidation() {
Validator v = getValidator();
if (v == null || mTokenizer == null) {
return;
}
Editable e = getText();
int i = getText().length();
while (i > 0) {
int start = mTokenizer.findTokenStart(e, i);
int end = mTokenizer.findTokenEnd(e, start);
CharSequence sub = e.subSequence(start, end);
if (TextUtils.isEmpty(sub)) {
e.replace(start, i, "");
} else if (!v.isValid(sub)) {
e.replace(start, i,
mTokenizer.terminateToken(v.fixText(sub)));
}
i = start;
}
}
/**
* <p>对下拉列表中的内容进行筛选.采用的模式是利用编辑框对指定范围的文本进行筛选.
* （The filtering pattern is the specified range of text from the edit box）
* 子类可覆盖此方法，以便于采用一个不同的模式.
* 例如，使用<code>text</code>的更小的子串进行筛选.</p>
*/
protected void performFiltering(CharSequence text, int start, int end,
int keyCode) {
getFilter().filter(text.subSequence(start, end), this);
}
/**
* <p>用 {@link Tokenizer#terminateToken} 方法处理完的
* <code>text</code> 来替换从 {@link Tokenizer#findTokenStart}
* 到 {@link #getSelectionEnd} 之间的内容.
* 另外，替换后的文本会标记为 AutoText 替换，如果用户立即按下 DEL 键，
* 会取消该替换操作.
* 子类可覆盖此方法，用于向编辑框中插入其它内容.</p>
*
* @param text 选中的下拉列表中的建议文本
*/
@Override
protected void replaceText(CharSequence text) {
clearComposingText();
int end = getSelectionEnd();
int start = mTokenizer.findTokenStart(getText(), end);
Editable editable = getText();
String original = TextUtils.substring(editable, start, end);
QwertyKeyListener.markAsReplaced(editable, start, end, original);
editable.replace(start, end, mTokenizer.terminateToken(text));
}
@Override
public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(event);
event.setClassName(MultiAutoCompleteTextView.class.getName());
}
@Override
public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
super.onInitializeAccessibilityNodeInfo(info);
info.setClassName(MultiAutoCompleteTextView.class.getName());
}
public static interface Tokenizer {
/**
* 返回 <code>text</code> 中，到 <code>cursor</code> 结束的标记的开始位置.
*/
public int findTokenStart(CharSequence text, int cursor);
/**
* 返回 <code>text</code> 中，从 <code>cursor</code> 开始的标记的结束位置.
* 不包含尾随分隔符.
*/
public int findTokenEnd(CharSequence text, int cursor);
/**
* 返回包含分割符的 <code>text</code>，如果不包含，则添加分隔符并返回修改后的值.
*/
public CharSequence terminateToken(CharSequence text);
}
/**
* 这个简易的分解器可用于对由逗号和若干空格分割的列表进行分解.
*/
public static class CommaTokenizer implements Tokenizer {
public int findTokenStart(CharSequence text, int cursor) {
int i = cursor;
while (i > 0 && text.charAt(i - 1) != ',') {
i--;
}
while (i < cursor && text.charAt(i) == ' ') {
i++;
}
return i;
}
public int findTokenEnd(CharSequence text, int cursor) {
int i = cursor;
int len = text.length();
while (i < len) {
if (text.charAt(i) == ',') {
return i;
} else {
i++;
}
}
return len;
}
public CharSequence terminateToken(CharSequence text) {
int i = text.length();
while (i > 0 && text.charAt(i - 1) == ' ') {
i--;
}
if (i > 0 && text.charAt(i - 1) == ',') {
return text;
} else {
if (text instanceof Spanned) {
SpannableString sp = new SpannableString(text + ", ");
TextUtils.copySpansFrom((Spanned) text, 0, text.length(),
Object.class, sp, 0);
return sp;
} else {
return text + ", ";
}
}
}
}
}