响应界面可见度变更

本课介绍了如何注册监听器，以便您的应用接收通知 系统界面可见性变更如果您想 使界面的其他部分与系统栏的隐藏/显示同步。

注册监听器

要获取有关系统界面可见性更改的通知，请注册 View.OnSystemUiVisibilityChangeListener添加到您的视图中。 这通常是您用来控制导航可见性的视图。

例如，您可以将此代码添加到 activity 的 onCreate() 方法：

Kotlin

window.decorView.setOnSystemUiVisibilityChangeListener { visibility ->
    // Note that system bars will only be "visible" if none of the
    // LOW_PROFILE, HIDE_NAVIGATION, or FULLSCREEN flags are set.
    if (visibility and View.SYSTEM_UI_FLAG_FULLSCREEN == 0) {
        // TODO: The system bars are visible. Make any desired
        // adjustments to your UI, such as showing the action bar or
        // other navigational controls.
    } else {
        // TODO: The system bars are NOT visible. Make any desired
        // adjustments to your UI, such as hiding the action bar or
        // other navigational controls.
    }
}

Java

View decorView = getWindow().getDecorView();
decorView.setOnSystemUiVisibilityChangeListener
        (new View.OnSystemUiVisibilityChangeListener() {
    @Override
    public void onSystemUiVisibilityChange(int visibility) {
        // Note that system bars will only be "visible" if none of the
        // LOW_PROFILE, HIDE_NAVIGATION, or FULLSCREEN flags are set.
        if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0) {
            // TODO: The system bars are visible. Make any desired
            // adjustments to your UI, such as showing the action bar or
            // other navigational controls.
        } else {
            // TODO: The system bars are NOT visible. Make any desired
            // adjustments to your UI, such as hiding the action bar or
            // other navigational controls.
        }
    }
});

一般而言，最好使界面与系统栏中的更改保持同步 可见性。例如，您可以使用此监听器在 同时隐藏和显示状态栏。