SoFunction
Updated on 2025-04-13

Summary of the difference and use of isHidden and isVisible in Qt

1. Basic concepts

In QtisHidden()andisVisible()Methods are all used to query the component to display or hide the state. However, they are very different and understanding them is essential for the correct operation of components.

  • isHidden(): Returns whether the component is explicitly set to a hidden state.
  • isVisible(): Returns whether the component is visible on the window, including considering the parent-child component state.

2. Clear difference

  • isHidden()Check only the hidden state of itself:
    • If calledhide(),butisHidden()returntrue ；
    • But if only the parent component is hidden,isHidden()Still returnfalse。
  • isVisible()The status of the full-level component will be considered:
    • If the component itself is not hidden, but the parent component is hidden,isVisible()returnfalse。

3. Actual cases

To calculate the state of a button, you can do this:

QPushButton *button = new QPushButton("Click Me", this);
button->hide();
qDebug() << "isHidden:" << button->isHidden();  // true
qDebug() << "isVisible:" << button->isVisible();  // false
button->show();
qDebug() << "isHidden:" << button->isHidden();  // false
qDebug() << "isVisible:" << button->isVisible();  // true

4. Things to note

  • isHidden()Records the hidden state of the component itself.
  • isVisible()Consider the entire component tree-level correlation.
  • If you want to check whether it is currently visible, useisVisible()。
  • If you only want to query your hidden state, useisHidden()。

5. Summary

In Qt development, understandisHidden()andisVisible()The difference can better control the UI structure and event triggering logic. When you need to know whether a component is related to whether the overall interface is visible,isVisible(); If you only care about the hidden state of the component itself, useisHidden()。

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