本课介绍如何注册监听器,以便应用接收有关系统界面可见性更改的通知。如果您想将界面的其他部分与系统栏的隐藏/显示同步,这将非常有用。
注册监听器
如需获取有关系统界面可见性更改的通知,请向视图中注册 View.OnSystemUiVisibilityChangeListener
。这通常是您用来控制导航可见性的视图。
例如,您可以将以下代码添加到 activity 的 onCreate()
方法中:
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. } } });
一般来说,最好使界面与系统栏可见性的变化保持同步。例如,您可以使用此监听器来隐藏和显示操作栏,同时隐藏和显示状态栏。