本課程將說明如何註冊事件監聽器,讓應用程式在系統 UI 瀏覽權限變更時通知應用程式。如果您想將 UI 的其他部分與隱藏/顯示系統資訊列同步處理,這個方法就非常實用。
註冊事件監聽器
如要接收系統 UI 瀏覽權限變更通知,請在檢視畫面中註冊 View.OnSystemUiVisibilityChangeListener
。一般來說,您可以使用的檢視畫面控制導覽瀏覽權限。
舉例來說,您可以將這段程式碼新增至活動的 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. } } });
一般而言,最佳做法是讓 UI 與系統列顯示設定的變更保持同步。舉例來說,您可以利用這個事件監聽器,在憑證中隱藏和顯示動作列,同時將狀態列隱藏和顯示。