QStatusBar

    QStatusBar* stBar = statusBar();

    QLabel* lb1 = new QLabel("标签1");       //
    lb1->setAlignment(Qt::AlignLeft);       //左对齐
    QLabel* lb2 = new QLabel("标签2");
    QLineEdit* edit = new QLineEdit("edit");
    QPushButton* btnOpen = new QPushButton("打开");

    stBar->addWidget(lb1);
    stBar->addWidget(lb2);
    stBar->addPermanentWidget(edit);
    stBar->addPermanentWidget(btnOpen);
    //stBar->showMessage("显示");

    lb1->setText("显示1");
    edit->setText("空内容");

（1）addPermanentWidget：在状态栏的右半部分添加组件。It is is located at the far right of the status bar

（2）addWidget：在状态栏的左半部分添加组件。The widget is located to the far left of the first permanent widget and may be obscured by temporary messages.

（3）showMessage：Hides the normal status indications and displays the given message for the specified number of milli-seconds