我希望允许用户一次查看字符串，N个字。它们可以向前和向后移动，这样向后将显示前N个单词。另外，由于我们受到屏幕空间的限制，所以我想只选择适合的单词，最多n个（整个单词，不...）。
所以，我创建了一个不太漂亮的方法：
import java.util.ArrayList;
public class Test {
static String text = "This is a dummny sentence. I am a dummy sentence two. This is dummy sentence 3. This is a dummy sentence";
static int currentWordIndex = 0;
public static void main(String[] args) {
String nextWords = getNextWords(5, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
nextWords = getNextWords(3, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
nextWords = getNextWords(3, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
nextWords = getNextWords(3, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
String prevWords = getPreviousWords(3, 30);
System.out.println("Previous Sentence: " + prevWords);
System.out.println("Index: " + currentWordIndex);
prevWords = getPreviousWords(3, 30);
System.out.println("PreviousSentence: " + prevWords);
System.out.println("Index: " + currentWordIndex);
prevWords = getPreviousWords(3, 30);
System.out.println("PreviousSentence: " + prevWords);
System.out.println("Index: " + currentWordIndex);
nextWords = getNextWords(3, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
nextWords = getNextWords(3, 30);
System.out.println("Sentence: " + nextWords);
System.out.println("Index: " + currentWordIndex);
}
public static String getPreviousWords(int n, int maxCharacterLength) {
ArrayList<String> initialSelection = new ArrayList();
String[] splitWords = text.split(" ");
int charCount = 0;
int maxN = currentWordIndex - n;
if(maxN < 0) {
maxN = 0;
}
for (int i = maxN; i < currentWordIndex; i++) {
if(i > splitWords.length) {
break;
}
initialSelection.add(splitWords[i]);
charCount += splitWords[i].length();
}
if (charCount > maxCharacterLength) {
charCount = 0;
for (int x = 0; x < initialSelection.size(); x++) {
if (initialSelection.size() == 0)
return null;
initialSelection.remove(initialSelection.size() - 1);
for (String s : initialSelection) {
charCount += s.length();
}
if (charCount <= maxCharacterLength) {
break;
}
}
}
StringBuilder sb = new StringBuilder();
for (String s : initialSelection) {
sb.append(s + " ");
}
if(currentWordIndex - initialSelection.size() < 0) {
currentWordIndex = 0;
} else {
currentWordIndex -= initialSelection.size();
}
return sb.toString().substring(0, sb.length());
}
/**
* Obtains the next n number of words given the maximum number of characters that can fit on the screen.
* If not all words fit on the screen
*
* @param n number of words
* @param maxCharacterLength of text that can fit on the screen.
* @return next words
*/
public static String getNextWords(int n, int maxCharacterLength) {
ArrayList<String> initialSelection = new ArrayList();
int charCount = 0;
String[] splitWords = text.split(" ");
int maxN = currentWordIndex + n;
if (maxN > splitWords.length - 1) {
maxN = splitWords.length - 1;
}
// add the words
for (int i = currentWordIndex; i < maxN; i++) {
if (i > splitWords.length - 1)
break;
initialSelection.add(splitWords[i]);
charCount += splitWords[i].length();
}
// if there's too many, remove the last word until everything fits
if (charCount > maxCharacterLength) {
charCount = 0;
for (int x = 0; x < initialSelection.size(); x++) {
if (initialSelection.size() == 0)
return null;
initialSelection.remove(initialSelection.size() - 1);
for (String s : initialSelection) {
charCount += s.length();
}
if (charCount <= maxCharacterLength) {
break;
}
}
}
// add back into a string
StringBuilder sb = new StringBuilder();
for (String s : initialSelection) {
sb.append(s + " ");
}
// update the index/pivot based on the words selected
if (currentWordIndex + initialSelection.size() < splitWords.length - 1) {
currentWordIndex += initialSelection.size();
} else {
currentWordIndex = splitWords.length;
}
return sb.toString().substring(0, sb.length());
}
}
这给出了这个输出：
Next Sentence: One two three four five.
Index: 5
Next Sentence: Six Seven Either,
Index: 8
Next Sentence: Nine, Ten, Eleven.
Index: 11
Next Sentence: Twelve thirdteen fourteen
Index: 14
Previous Sentence: Twelve thirdteen fourteen
Index: 11
PreviousSentence: Nine, Ten, Eleven.
Index: 8
PreviousSentence: Six Seven Either,
Next Index: 5
Next Sentence: Six Seven Either,
Index: 8
Next Sentence: Nine, Ten, Eleven.
Index: 11
哪个不对。它似乎是下一个和前一个工作 - 只是在它们之间进行更改时。它应该说：
Next Sentence: One two three four five.
Index: 5
Next Sentence: Six Seven Either,
Index: 8
Next Sentence: Nine, Ten, Eleven.
Index: 11
Next Sentence: Twelve thirdteen fourteen
Index: 14
Previous Sentence: Nine, Ten, Eleven.
Index: 11
PreviousSentence: Six, Seven, Either.
Index: 8
PreviousSentence: three four five,
Index: 5
Next Sentence: Six Seven Either,
Index: 8
Next Sentence: Nine, Ten, Eleven.
Index: 11
我明白问题是什么：在getNext“递增之后，它在下一个句子的开头设置标记。因此当调用'getPrevious'时，它调用，最后一个句子（当前已经显示的那个） 。
所以我认为解决方案是同时具有开始和结束标记 - 标记句子索引的开头和结尾。
但我想知道是否有人有更优雅的解决方案来解决这个问题？
答案 0 :(得分：2)
试试这个
public class Test {
static String text = "one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen";
static int currentWordIndex = 0;
private static List<String> list = new LinkedList<String>();
public void createTokens() {
String[] splitWords = text.split(" ");
for (int i = 0; i < splitWords.length; i++) {
list.add(splitWords[i]);
}
}
public String getPreviousWords(int n, int maxCharacterLength) {
StringBuilder strBuilder = new StringBuilder();
int characterCount = 0;
int item_size = 0;
// you need to check this negative or not
currentWordIndex = currentWordIndex - n;
ListIterator<String> nextIter = list.listIterator(currentWordIndex);
while (nextIter.hasPrevious() && item_size < n) {
String elem = (String) nextIter.previous();
characterCount += elem.length();
if (characterCount > maxCharacterLength) {
break;
}
strBuilder.append(elem);
strBuilder.append(" ");
item_size++;
}
return strBuilder.toString();
}
/**
* Obtains the next n number of words given the maximum number of characters
* that can fit on the screen. If not all words fit on the screen
*
* @param n
* number of words
* @param maxCharacterLength
* of text that can fit on the screen.
* @return next words
*/
public String getNextWords(int n, int maxCharacterLength) {
StringBuilder strBuilder = new StringBuilder();
int characterCount = 0;
int item_size = 0;
ListIterator<String> nextIter = list.listIterator(currentWordIndex);
while (nextIter.hasNext() && item_size < n) {
String elem = (String) nextIter.next();
characterCount += elem.length();
if (characterCount > maxCharacterLength) {
break;
}
strBuilder.append(elem);
strBuilder.append(" ");
item_size++;
}
return strBuilder.toString();
}
}
App.java
public class App {
public static void main(String[] args) {
Test t = new Test();
t.createTokens();
String nextWords = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords);
String nextWords2 = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords2);
String nextWords3 = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords3);
String previousWords = t.getPreviousWords(5, 30);
System.out.println("Sentence: " + previousWords);
}
}
输出：
Sentence: one two three four five
Sentence: six seven eight nine ten
Sentence: eleven twelve thirteen fourteen
Sentence: ten nine eight seven six
答案 1 :(得分：0)
因为我想让它与@mithat konuk解决方案合作。但我认为这可能会更好地与子列表。
public class Test2 {
public static void main(String[] args) {
Test2 t = new Test2();
t.createTokens();
String nextWords = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords);
String nextWords2 = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords2);
String nextWords3 = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords3);
String previousWords = t.getPreviousWords(3, 10);
System.out.println("Previous Sentence: " + previousWords);
previousWords = t.getPreviousWords(3, 10);
System.out.println("Previous Sentence: " + previousWords);
previousWords = t.getPreviousWords(3, 10);
System.out.println("Previous Sentence: " + previousWords);
previousWords = t.getPreviousWords(3, 10);
System.out.println("Previous Sentence: " + previousWords);
previousWords = t.getPreviousWords(3, 10);
System.out.println("Previous Sentence: " + previousWords);
nextWords = t.getNextWords(5, 30);
System.out.println("Sentence: " + nextWords);
}
static String text = "I am a cat who sat on a mat and yelled as someone who was fat";
private static List<String> list = new LinkedList<String>();
// index of the start of the next sentence (i.e also the end of the sentence that is currently being displayed)
static int nextWordIndex = 0;
// index of the first word of the current sentence being displayed.
static int firstWordIndex = 0;
public void createTokens() {
String[] splitWords = text.split(" ");
for (int i = 0; i < splitWords.length; i++) {
list.add(splitWords[i]);
}
}
public String getPreviousWords(int n, int maxCharacterLength) {
StringBuilder strBuilder = new StringBuilder();
int characterCount = 0;
int itemSize = 0;
// you need to check this negative or not
if(firstWordIndex < 0)
firstWordIndex = 0;
ListIterator<String> nextIter = list.listIterator(firstWordIndex);
while (nextIter.hasPrevious() && itemSize < n) {
String elem = (String) nextIter.previous();
characterCount += elem.length();
if (characterCount > maxCharacterLength) {
break;
}
strBuilder.insert(0, elem + " ");
itemSize++;
}
if(firstWordIndex == 0) {
firstWordIndex = 0;
nextWordIndex = itemSize;
}
nextWordIndex = firstWordIndex;
firstWordIndex-=itemSize;
return strBuilder.toString();
}
/**
* Obtains the next n number of words given the maximum number of characters
* that can fit on the screen. If not all words fit on the screen
*
* @param n
* number of words
* @param maxCharacterLength
* of text that can fit on the screen.
* @return next words
*/
public String getNextWords(int n, int maxCharacterLength) {
StringBuilder strBuilder = new StringBuilder();
int characterCount = 0;
int itemSize = 0;
ListIterator<String> nextIter = list.listIterator(nextWordIndex);
while (nextIter.hasNext() && itemSize < n) {
String elem = (String) nextIter.next();
characterCount += elem.length();
if (characterCount > maxCharacterLength) {
break;
}
strBuilder.append(elem);
strBuilder.append(" ");
itemSize++;
}
firstWordIndex = nextWordIndex;
nextWordIndex+=itemSize;
return strBuilder.toString();
}
}
输出：
句子：我是一个句子：坐在垫子上的猫和句子：大喊 作为先前句子的人：垫子和前句子： 谁坐在上一句话：我是一只猫以前的句子：我 上一句：句子：我是一只猫