获取java jTextArea中String文本的开始和结束位置

Question

I am implementing a spellchecker using apached lucene 3.6 Want to integrate the highlighting of mispelled words with the Highlight class using the "start" and "end" position of the words.

Will like to know how to get start and end positions of text as they are entered into the jtextarea.

I know will have to use keyboard and mouse event listeners.

But how do I get the "start" and "end" position of each word in the string of text.

thank you.

Answer 1

Assuming "words" are just defined as characters groups separated by spaces, you can find the index of all spaces like so:

int index = 0;
String string = ... // get from text area
while((index = string.indexOf(' ', index)) != -1) {
   // save them      
}

You could take the resulting list of space indexes and build a list of Word objects, eliminating words of zero length (adjacent space indexes), etc.

Answer 2

You need to call getText() to get the complete text in the text area as a String. Then you can get the words out of this String, check them, and also in the same step get the indices of the words and their end indices, which are simply start index+wordlength.

Answer 3

Could you not just get the jTextArea and split the string at spaces. This would give you an array of all the "words" in the area.

String text = jTextArea.getText();
String[] words = text.split(' ');

Then to get the index of the words you just add up the length of the word + 1 for the space.

int[] startIndices = new int[words.length];
int[] endIndices = new int[words.length];
int currentIndex = 0;
for (int i = 0; i < words.length; i++) {
    startIndices[i] = currentIndex;
    currentIndex += words[i].length;
    endIndices[i] = currentIndex;
    currentIndex++;
}