10、UI 对象

在前面的几个例子中已经见到了 UI 对象.

Ui::DemoClass ui; ui.setupUi(this); connect(ui.pushButton_4, SIGNAL(clicked()), this, SLOT(On_Out())); connect(ui.pushButton_5, SIGNAL(clicked()), this, SLOT(On_Out())); connect(ui.pushButton_6, SIGNAL(clicked()), this, SLOT(On_Out()));

那这个 UI 对象是什么呢?

在 VS + Qt 开发环境中, 通过使用 Qt Designer 编辑 *.ui 文件来设计界面.

设计好界面后, vs 就会把 *.ui 文件转换成对应的头文件, 这个头文件中包含了一个界面类.

<span style="color: #0000ff;">class</span><span style="color: #000000;"> Ui_DemoClass
{
</span><span style="color: #0000ff;">public</span><span style="color: #000000;">:
    QLabel </span>*<span style="color: #000000;">label;

    </span><span style="color: #0000ff;">void</span> setupUi(QWidget *<span style="color: #000000;">DemoClass)
    {
        </span><span style="color: #0000ff;">if</span> (DemoClass-><span style="color: #000000;">objectName().isEmpty())
            DemoClass</span>->setObjectName(QStringLiteral(<span style="color: #800000;">"</span><span style="color: #800000;">DemoClass</span><span style="color: #800000;">"</span><span style="color: #000000;">));
        DemoClass</span>->resize(<span style="color: #800080;">275</span>, <span style="color: #800080;">167</span><span style="color: #000000;">);
        label </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> QLabel(DemoClass);
        label</span>->setObjectName(QStringLiteral(<span style="color: #800000;">"</span><span style="color: #800000;">label</span><span style="color: #800000;">"</span><span style="color: #000000;">));
        label</span>->setGeometry(QRect(<span style="color: #800080;">90</span>, <span style="color: #800080;">60</span>, <span style="color: #800080;">71</span>, <span style="color: #800080;">31</span><span style="color: #000000;">));

        retranslateUi(DemoClass);

        QMetaObject::connectSlotsByName(DemoClass);
    } </span><span style="color: #008000;">//</span><span style="color: #008000;"> setupUi</span>

    <span style="color: #0000ff;">void</span> retranslateUi(QWidget *<span style="color: #000000;">DemoClass)
    {
        DemoClass</span>->setWindowTitle(QApplication::translate(<span style="color: #800000;">"</span><span style="color: #800000;">DemoClass</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">Demo</span><span style="color: #800000;">"</span>, <span style="color: #800080;">0</span><span style="color: #000000;">));
        label</span>->setText(QApplication::translate(<span style="color: #800000;">"</span><span style="color: #800000;">DemoClass</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">Hello Qt!</span><span style="color: #800000;">"</span>, <span style="color: #800080;">0</span><span style="color: #000000;">));
    } </span><span style="color: #008000;">//</span><span style="color: #008000;"> retranslateUi</span>
<span style="color: #000000;">
};

</span><span style="color: #0000ff;">namespace</span><span style="color: #000000;"> Ui {
    </span><span style="color: #0000ff;">class</span> DemoClass: <span style="color: #0000ff;">public</span><span style="color: #000000;"> Ui_DemoClass {};
} </span><span style="color: #008000;">//</span><span style="color: #008000;"> namespace Ui</span><span style="color: #000000;">
</span>

看到这里就比较明白了, 这个界面类声明了界面上所用到的控件对象, 通过 setupUi 成员函数来设计界面布局.

使用的时候, 在自定义类里面引用这个界面类, 声明一个UI的成员对象, 调用setUPUi函数.

<span style="color: #000000;">Ui::DemoClass ui;
ui.setupUi(</span><span style="color: #0000ff;">this</span>);

t#2

☠