【发布时间】：2020-03-31 14:22:14
【问题描述】：
我有一个基于单个活动和多个片段的应用程序，一些片段在进入片段时需要全屏显示，退出时从全屏退出。我目前正在使用标志在Android Kitkat 中显示全屏，但我认为这不是最佳方式。我还阅读了ImmersiveMode，但它不适用于较低的 Android 版本。目前我正在使用这些方法进行全屏进入和退出。
//This method not showing transparent status bar also navigation bar and not showing system icons either
public static void setFullscreen(Activity activity) {
if (Build.VERSION.SDK_INT > 10) {
int flags = View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_FULLSCREEN;
boolean isImmersiveAvailable = android.os.Build.VERSION.SDK_INT >= 19;
if (isImmersiveAvailable) {
flags |= View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION |
View.SYSTEM_UI_FLAG_HIDE_NAVIGATION | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
}
activity.getWindow().getDecorView().setSystemUiVisibility(flags);
} else {
activity.getWindow()
.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
}
}
public static void exitFullscreen(Activity activity) {
if (Build.VERSION.SDK_INT > 10) {
activity.getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE);
} else {
activity.getWindow()
.setFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
}
}
public static void ShowHideFullscreen(boolean isFullscreen,Context cntx){
int newUiOptions = 0;
if (isFullscreen){
// BEGIN_INCLUDE (get_current_ui_flags)
// The UI options currently enabled are represented by a bitfield.
// getSystemUiVisibility() gives us that bitfield.
int uiOptions = ((Activity)cntx).getWindow().getDecorView().getSystemUiVisibility();
newUiOptions = uiOptions;
// END_INCLUDE (get_current_ui_flags)
// BEGIN_INCLUDE (toggle_ui_flags)
boolean isImmersiveModeEnabled =
((uiOptions | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY) == uiOptions);
if (isImmersiveModeEnabled) {
Log.d(TAG, "Turning immersive mode mode off. ");
} else {
Log.d(TAG, "Turning immersive mode mode on.");
}
// Navigation bar hiding: Backwards compatible to ICS.
if (Build.VERSION.SDK_INT >= 14) {
newUiOptions ^= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
}
// Status bar hiding: Backwards compatible to Jellybean
if (Build.VERSION.SDK_INT >= 16) {
newUiOptions ^= View.SYSTEM_UI_FLAG_FULLSCREEN;
}
// Immersive mode: Backward compatible to KitKat.
// Note that this flag doesn't do anything by itself, it only augments the behavior
// of HIDE_NAVIGATION and FLAG_FULLSCREEN. For the purposes of this sample
// all three flags are being toggled together.
// Note that there are two immersive mode UI flags, one of which is referred to as "sticky".
// Sticky immersive mode differs in that it makes the navigation and status bars
// semi-transparent, and the UI flag does not get cleared when the user interacts with
// the screen.
if (Build.VERSION.SDK_INT >= 18) {
newUiOptions ^= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
}
((Activity)cntx).getWindow().getDecorView().setSystemUiVisibility(newUiOptions);
}else {
((Activity)cntx).getWindow().clearFlags(newUiOptions);
}
}
这些是我们用来在带有隐藏操作栏的片段中进入或退出全屏的方法。我们使用这些在onCreate 上全屏输入并在onPause 上退出，但有时它无法显示所需的结果。
我们也需要知道在较低的 API 上显示全屏片段的最佳方式是什么（KITKAT），以及在全屏显示时隐藏工具栏的最佳方式是什么，因为我们的代码 ((AppCompatActivity)Objects.requireNonNull(getActivity())).getSupportActionBar().hide();
有时会抛出空指针异常。
我们的问题：
- 在全屏片段和透明导航栏上显示带有透明状态栏和绘图系统图标的全屏片段。
- 使用无需获取
NullpointerExepection即可安全调用的方法隐藏和显示工具栏 - 我们可以将 Android Kitkat 定位为最低的 android 版本。
更新：我在片段onResume 上设置了IMMERSIVE 模式，并通过这些方法将其重置回onStop。
private void hideSystemUI() {
// Enables regular immersive mode.
// For "lean back" mode, remove SYSTEM_UI_FLAG_IMMERSIVE.
// Or for "sticky immersive," replace it with SYSTEM_UI_FLAG_IMMERSIVE_STICKY
View decorView = getActivity().getWindow().getDecorView();
decorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
// Set the content to appear under the system bars so that the
// content doesn't resize when the system bars hide and show.
| View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
// Hide the nav bar and status bar
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN);
((AppCompatActivity) Objects.requireNonNull(getActivity())).getSupportActionBar().hide();
}
// Shows the system bars by removing all the flags
// except for the ones that make the content appear under the system bars.
private void showSystemUI() {
View decorView = getActivity().getWindow().getDecorView();
decorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
((AppCompatActivity) Objects.requireNonNull(getActivity())).getSupportActionBar().show();
}
它以全屏显示我的片段，隐藏状态栏（这不是我想要的），我的片段属于Navigation Drawer。当我从全屏片段按下返回按钮时，它会在前一个片段的工具栏上显示我的状态栏。
【问题讨论】：
标签： android android-fragments android-actionbar