Android布局——水滴屏全屏设置

提出问题：在水滴屏Android手机上如何实现全屏展示。

探究发现：
1、ViewGroup.LayoutParams（官网解释，Summary）
该类继承自java.lang.Object。该类的属性很少，因为只有三个变量和三个int型常量，如下表所示。它还有三个不同的构造函数，其中包含一个copy构造函数。

常量
FILL_PARENT、MATCH_PARENT、WRAP_PARENT
变量
height、width、layoutAnimationParameters

2、WindowManager.LayoutParams（官网解释）
该类直接继承ViewGroup.LayoutParams，并且实现了接口Parcelable。它的内容比它的父类多了很多。它的属性中有大量的常量（所以，单独将这些常量拿到一篇博客中，点击此处可以浏览这些常量）。关于布局的常量见下面所示。

---

• int FLAGS_CHANGED
• int FLAG_FULLSCREEN
  This constant was deprecated in API level R. Use WindowInsetsController#hide(int) with Type#statusBars() instead.
  最新的Android 11建议废弃这个常量。
  Window flag: hide all screen decorations (such as the status bar) while this window is displayed. This allows the window to use the entire display space for itself – the status bar will be hidden when an app window with this flag set is on the top layer. A fullscreen window will ignore a value of SOFT_INPUT_ADJUST_RESIZE for the window’s softInputMode field; the window will stay fullscreen and will not resize.
  窗口标志：显示此窗口时隐藏所有屏幕装饰（如状态栏）。这允许窗口为自己使用整个显示空间——当设置了此标志的应用程序窗口位于顶层时，状态栏将被隐藏。全屏窗口将忽略窗口的softInputMode字段的SOFT_INPUT_ADJUST_RESIZE值；窗口将保持全屏，并且不会调整大小。
• int FLAG_LAYOUT_NO_LIMITS
  Window flag: allow window to extend outside of the screen.
  窗口标志：允许窗口扩展到屏幕之外。

---

• int LAYOUT_CHANGED
• int LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS
  The window is always allowed to extend into the DisplayCutout areas on the all edges of the screen.
  窗口总是可以扩展到屏幕所有边缘上的显示剪切区域。
• int LAYOUT_IN_DISPLAY_CUTOUT_MODE_DEFAULT
  The window is allowed to extend into the DisplayCutout area, only if the DisplayCutout is fully contained within a system bar.
  仅当系统栏中完全包含DisplayCutout时，才允许窗口扩展到DisplayCutout区域。
• int LAYOUT_IN_DISPLAY_CUTOUT_MODE_NEVER
  The window is never allowed to overlap with the DisplayCutout area.
  窗口永远不允许与显示剪切区重叠。
• int LAYOUT_IN_DISPLAY_CUTOUT_MODE_SHORT_EDGES
  The window is always allowed to extend into the DisplayCutout areas on the short edges of the screen.
  窗口总是可以延伸到屏幕短边上的显示剪切区域。

---

变量：

• public int flags
  Various behavioral options/flags.
• public int layoutInDisplayCutoutMode
  Controls how the window is laid out if there is a DisplayCutout.
• public int systemUiVisibility
  This field was deprecated in API
  level R. SystemUiVisibility flags are deprecated. Use
  WindowInsetsController instead.

---

3、如何将参数设置到目的对象
因为调用Activity.getWindow()方法可以返回一个Window对象，进而通过Window.getAttributes()方法可以获得WindowManager.LayoutParams对象。

//某个Avtivity的onCreate方法中
WindowManager.LayoutParams layoutParams = getWindow().getAttributes();

解决方案：

public static void fullScreen(final Activity activity, final boolean enable) {
        if(activity == null){
            return;
        }
        Window window = activity.getWindow();
        WindowManager.LayoutParams layoutParams = window.getAttributes();
        if (enable) {
            layoutParams.layoutInDisplayCutoutMode = WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_SHORT_EDGES;
            layoutParams.flags |= WindowManager.LayoutParams.FLAG_FULLSCREEN;
            window.addFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        } else {
            layoutParams.layoutInDisplayCutoutMode = WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_DEFAULT;
            layoutParams.flags &= (~WindowManager.LayoutParams.FLAG_FULLSCREEN);
            window.clearFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        }
        window.setAttributes(layoutParams);
    }

感谢微博 有个小男神 https://blog.csdn.net/qq912098812/article/details/77369872