QSplitter

The QSplitter class implements a splitter widget.
A splitter lets the user control the size of child widgets by dragging the boundary between them. Any number of widgets may be controlled by a single splitter. The typical use of a QSplitter is to create several widgets and add them using insertWidget() or addWidget().

QSplitter类实现了一个分离小部件。
splitter允许用户通过拖动子部件之间的边界来控制它们的大小。
任何数量的小部件都可以由单个拆分器控制。QSplitter的典型用法是创建几个小部件并使用
insertWidget()或addWidget()添加它们。

看一个例子

this->setWindowTitle("码农小明--QSplitter");

    QSplitter* splitter = new QSplitter(this);
    splitter->setFixedSize(500,500);

    QTextEdit* textEdit1 = new QTextEdit();
    QTextEdit* textEdit2 = new QTextEdit();
    QTextEdit* textEdit3 = new QTextEdit();

    splitter->addWidget(textEdit1);
    splitter->addWidget(textEdit2);
    splitter->addWidget(textEdit3);

    textEdit1->setText("Edit1");
    textEdit1->setAlignment(Qt::AlignCenter);

    textEdit2->setText("Edit2");
    textEdit2->setAlignment(Qt::AlignCenter);

    textEdit3->setText("Edit3");
    textEdit3->setAlignment(Qt::AlignCenter);


    this->setFixedSize(500,500);

If a widget is already inside a QSplitter when insertWidget() or addWidget() is called,
it will move to the new position. This can be used to reorder widgets in the splitter later. 
You can use indexOf(), widget(), and count() to get access to the widgets inside the splitter.

如果在调用insertWidget()或addWidget()时，一个小部件已经在QSplitter中，那么它将移动到新的位置。
这可以用于稍后在拆分器中重新排序小部件。您可以使用indexOf()、widget()和count()来访问splitter中的小部件。

qDebug()<<"splitter->count:"<<splitter->count();

QSplitter 把 widget 横向的分为 3个widget (默认方向为 横向)

A default QSplitter lays out its children horizontally (side by side); 
you can use setOrientation(Qt::Vertical) to lay its children out vertically.

默认的QSplitter水平地(并排地)布局它的子组件;
你可以使用setOrientation(Qt::Vertical)功能将其子机器人垂直放置。

splitter->setOrientation(Qt::Vertical);//设置方向为垂直

QSplitter resizes its children dynamically by default. 
If you would rather have QSplitter resize the children only at the end of a resize operation, 
call setOpaqueResize(false).

默认情况下，QSplitter会动态调整其子元素的大小。如果您希望QSplitter仅在调整大小操作结束时调整子元素的大小，
那么调用setOpaqueResize(false)

默认的true

splitter->setOpaqueResize(true);//默认的true

效果:

splitter->setOpaqueResize(false);

效果:

区别很明显就是 能不能实时的预览到 拖拽时的画面

The initial distribution of size between the widgets is determined by multiplying
the initial size with the stretch factor. 
The function sizes() returns the sizes set by the user. 
Alternatively, you can save and restore the sizes of the widgets from a 
QByteArray using saveState() and restoreState() respectively.

小部件之间大小的初始分布是通过将初始大小与伸缩因子相乘确定的。
您还可以使用setsize()来设置所有小部件的大小
。函数size()返回用户设置的大小。
或者，您可以分别使用saveState()和restoreState()从QByteArray中保存和恢复小部件的大小。

看一下 void QSplitter::setSizes(const QList<int> &list)

Sets the child widgets' respective sizes to the values given in the list.
If the splitter is horizontal, the values set the width of each widget in pixels,
from left to right. If the splitter is vertical, the height of each widget is set, 
from top to bottom.

将子部件的各自大小设置为列表中给定的值。
如果splitter是水平的，则这些值将以像素为单位设置每个小部件的宽度，从左到右。
如果splitter是垂直的，则从上到下设置每个小部件的高度

    QList<int> list;
    list<<50<<100<<200;//width 为 50 100 200

    splitter->setSizes(list);

注意:

Note: Adding a QLayout to a QSplitter is not supported (either through setLayout() or
making the QSplitter a parent of the QLayout); use addWidget() instead (see example above).

不支持向QSplitter添加QLayout(通过setLayout()或将QSplitter作为QLayout的父元素);
使用addWidget()代替(参见上面的例子)。

    this->setWindowTitle("码农小明--QSplitter");

    QSplitter* splitter = new QSplitter(this);
    splitter->setFixedSize(500,500);

    QTextEdit* textEdit1 = new QTextEdit();
    QTextEdit* textEdit2 = new QTextEdit();
    QTextEdit* textEdit3 = new QTextEdit();
    QTextEdit* textEdit4 = new QTextEdit();


    splitter->addWidget(textEdit1);


    textEdit1->setText("Main-Left");
    textEdit1->setAlignment(Qt::AlignCenter);

    textEdit2->setText("Right-Top");
    textEdit2->setAlignment(Qt::AlignCenter);

    QSplitter* splitter2 = new QSplitter(splitter);
    splitter2->setOrientation(Qt::Vertical);

    splitter2->addWidget(textEdit2);

    textEdit3->setText("Right-Bottom-left");
    textEdit3->setAlignment(Qt::AlignCenter);

    textEdit4->setText("Right-Bottom-right");
    textEdit4->setAlignment(Qt::AlignCenter);

    QSplitter* splitter3 = new QSplitter(splitter2);

    splitter3->addWidget(textEdit3);
    splitter3->addWidget(textEdit4);


    this->setFixedSize(500,500);

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