本课介绍如何注册监听器,以便让应用获得系统界面可见性变更通知。如果您希望将界面的其他部分与系统栏的隐藏/显示同步,这会非常有用。
注册监听器
要获得有关系统界面可见性更改的通知,请向您的视图注册 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变更保持同步。例如,您可以使用此监听器,随着状态栏的隐藏和显示来隐藏和显示操作栏。