QPlainTextEdit

main.cpp

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#include <QPlainTextEdit>
#include <QVBoxLayout>
#include <QPushButton>
#include <QLabel>
#include <QTime>
#include <qapplication.h>

void setupPlainTextEditDemo(QWidget *parent) {
    QVBoxLayout *layout = new QVBoxLayout(parent);

    // --- 1. 创建纯文本编辑器 ---
    QPlainTextEdit *plainEdit = new QPlainTextEdit(parent);
    plainEdit->setPlaceholderText("这里是纯文本模式（适合显示大批量日志或代码）...");

    // 常用配置：设置最大块数（防止日志无限增长导致内存崩溃）
    plainEdit->setMaximumBlockCount(100); // 只保留最新的100行

    // --- 2. 模拟日志追加按钮 ---
    QPushButton *btnLog = new QPushButton("模拟产生一条日志", parent);
    QObject::connect(btnLog, &QPushButton::clicked, [plainEdit]() {
        QString timeStr = QTime::currentTime().toString("hh:mm:ss.zzz");
        // appendPlainText 自动换行追加，不会破坏之前的格式
        plainEdit->appendPlainText(QString("[%1] 系统运行正常，数据处理中...").arg(timeStr));
    });

    // --- 3. 实时行数统计 ---
    QLabel *lineCountLabel = new QLabel("当前行数：1", parent);
    QObject::connect(plainEdit, &QPlainTextEdit::blockCountChanged, [lineCountLabel](int newBlockCount) {
        lineCountLabel->setText(QString("当前行数：%1").arg(newBlockCount));
    });

    // --- 4. 只读切换 ---
    QPushButton *btnReadOnly = new QPushButton("切换只读/编辑状态", parent);
    btnReadOnly->setCheckable(true);
    QObject::connect(btnReadOnly, &QPushButton::toggled, [plainEdit](bool checked) {
        plainEdit->setReadOnly(checked);
        plainEdit->setStyleSheet(checked ? "background-color: #f0f0f0;" : "");
    });

    layout->addWidget(new QLabel("日志/纯文本编辑器："));
    layout->addWidget(plainEdit);
    layout->addWidget(lineCountLabel);
    layout->addWidget(btnLog);
    layout->addWidget(btnReadOnly);
}
int main(int argc, char *argv[]) {
    QApplication a(argc, argv);

    QWidget w;
    w.setWindowTitle("QLineEdit 深度测试");
    w.resize(400, 300);

    // 调用我们的函数
    setupPlainTextEditDemo(&w);

    w.show();
    return a.exec();
}