Question

我的搜索方法有问题。

使用这种方法，我可以在文本字段中输入一个单词，然后在文本区域中显示该单词。但是，如果我让它运行，只会发生一次。我需要对其进行扩展，以便每次单击“输入”时，程序都应继续在文本区域中进行搜索。我怎样才能做到这一点？并且请给我代码示例。我只剩下2天的演讲时间。

非常感谢您的帮助

unsigned hextodigit(int hex)
{
    unsigned result = 0;

    switch(toupper(hex))
    {
        case '0':
            return 0;
            break;
        case '1':
            return 1;
            break;
        case '2':
            return 2;
            break;
        case '3':
            return 3;
            break;
        case '4':
            return 4;
            break;
        case '5':
            return 5;
            break;
        case '6':
            return 6;
            break;
        case '7':
            return 7;
            break;
        case '8':
            return 8;
            break;
        case '9':
            return 9;
            break;
        case 'A':
            return 10;
            break;
        case 'B':
            return 11;
            break;
        case 'C':
            return 12;
            break;
        case 'D':
            return 13;
            break;
        case 'E':
            return 14;
            break;
        case 'F':
            return 15;
            break;
        default:
            break;
    }
}


unsigned fromhex4chars(const char *str)
{
    return hextodigit(*(str + 3)) + (hextodigit(*(str + 2)) << 4) + (hextodigit(*(str + 1)) << 8) + (hextodigit(*str) << 12);    
}

void convert(const char *str, unsigned *buff)
{
    size_t len = strlen(str)  / 4;

    while(len--)
    {
        *buff++ = fromhex4chars(str);
        str += 4;
    }
}

int main(int argc, char **argv)
{
    unsigned x[100];

    convert(argv[1], x);


    return 0;
}

Answer 1

有一个overloaded version of the indexOf method，可让您从特定的索引开始搜索。跟踪最后找到的索引，然后从该位置开始搜索：

@Override
public void start(Stage primaryStage) throws Exception {

    TextField textField = new TextField("foo");
    TextArea textarea = new TextArea();
    for (int i = 0; i < 10; i++) {
        textarea.appendText("foo\nbarfoobarfoofoo\n");
    }

    textField.setOnAction(evt -> {
        String searchText = textField.getText();
        if (searchText.isEmpty()) {
            return; // searching for empty text doesn't make sense
        }
        int index = textarea.getSelection().getEnd();

        // in case of the first search, start at the beginning
        // TODO: adjust condition/starting index according to needs
        if (textarea.getSelection().getLength() == 0) {
            index = 0;
        }

        // find next occurrence
        int newStartIndex = textarea.getText().indexOf(searchText, index);

        // mark occurrence
        if (newStartIndex >= 0) {
            textarea.selectRange(newStartIndex, newStartIndex + searchText.length());
        }
    });

    Scene scene = new Scene(new VBox(textField, textarea));
    primaryStage.setScene(scene);
    primaryStage.show();
}

编辑

如果您对选择后的元素不满意（或者在光标之后，如果未选择范围），则可以保存最后匹配末尾的数据：

@Override
public void start(Stage primaryStage) throws Exception {

    TextField textField = new TextField("foo");
    TextArea textarea = new TextArea();
    for (int i = 0; i < 10; i++) {
        textarea.appendText("foo\nbarfoobarfoofoo\n");
    }

    class SearchHandler implements EventHandler<ActionEvent> {
        int index = 0;

        @Override
        public void handle(ActionEvent event) {
            String searchText = textField.getText();
            String fullText = textarea.getText();

            if (index + searchText.length() > fullText.length()) {
                // no more matches possible
                // TODO: notify user
                return;
            }
            // find next occurrence
            int newStartIndex = textarea.getText().indexOf(searchText, index);

            // mark occurrence
            if (newStartIndex >= 0) {
                index = newStartIndex + searchText.length();
                textarea.selectRange(newStartIndex, index);
            } else {
                index = fullText.length();
                // TODO: notify user
            }
        }

    }

    SearchHandler handler = new SearchHandler();
    textField.setOnAction(handler);
    // reset index to search from start when changing the text of the TextField
    textField.textProperty().addListener((o, oldValue, newValue) -> handler.index = 0);

    Scene scene = new Scene(new VBox(textField, textarea));
    primaryStage.setScene(scene);
    primaryStage.show();
}

通过按键搜索单词输入

1 个答案:

编辑