Support changing window manager params

This enables support for changing the various WindowManager
parameters documented here:
https://developer.android.com/reference/android/view/WindowManager.LayoutParams

either via NativeActivity_setWindowFlags or GameActivity_setWindowFlags

Fixes: #25

android-activity/src/game_activity/mod.rs

@@ -23,7 +23,7 @@ use ndk::asset::AssetManager;
 use ndk::configuration::Configuration;
 use ndk::native_window::NativeWindow;
 
-use crate::{util, AndroidApp, ConfigurationRef, MainEvent, PollEvent, Rect};
+use crate::{util, AndroidApp, ConfigurationRef, MainEvent, PollEvent, Rect, WindowManagerFlags};
 
 mod ffi;
 
@@ -309,6 +309,17 @@ impl AndroidAppInner {
         }
     }
 
+    pub fn set_window_flags(
+        &self,
+        add_flags: WindowManagerFlags,
+        remove_flags: WindowManagerFlags,
+    ) {
+        unsafe {
+            let activity = (*self.native_app.as_ptr()).activity;
+            ffi::GameActivity_setWindowFlags(activity, add_flags.bits(), remove_flags.bits())
+        }
+    }
+
     pub fn enable_motion_axis(&mut self, axis: Axis) {
         unsafe { ffi::GameActivityPointerAxes_enableAxis(axis as i32) }
     }

android-activity/src/lib.rs

@@ -6,6 +6,8 @@ use std::time::Duration;
 use ndk::asset::AssetManager;
 use ndk::native_window::NativeWindow;
 
+use bitflags::bitflags;
+
 #[cfg(not(target_os = "android"))]
 compile_error!("android-activity only supports compiling for Android");
 
@@ -170,9 +172,174 @@ pub enum PollEvent<'a> {
 }
 
 use activity_impl::AndroidAppInner;
-
 pub use activity_impl::AndroidAppWaker;
 
+bitflags! {
+    /// Flags for [`AndroidApp::set_window_flags`]
+    /// as per the [android.view.WindowManager.LayoutParams Java API](https://developer.android.com/reference/android/view/WindowManager.LayoutParams)
+    pub struct WindowManagerFlags: u32 {
+        /// As long as this window is visible to the user, allow the lock
+        /// screen to activate while the screen is on.  This can be used
+        /// independently, or in combination with
+        /// [`Self::KEEP_SCREEN_ON`] and/or [`Self::SHOW_WHEN_LOCKED`]
+        const ALLOW_LOCK_WHILE_SCREEN_ON = 0x00000001;
+
+        /// Everything behind this window will be dimmed. */
+        const DIM_BEHIND = 0x00000002;
+
+        /// Blur everything behind this window.
+        #[deprecated = "Blurring is no longer supported"]
+        const BLUR_BEHIND = 0x00000004;
+
+        /// This window won't ever get key input focus, so the
+        /// user can not send key or other button events to it.  Those will
+        /// instead go to whatever focusable window is behind it.  This flag
+        /// will also enable [`Self::NOT_TOUCH_MODAL`] whether or not
+        /// that is explicitly set.
+        ///
+        /// Setting this flag also implies that the window will not need to
+        /// interact with
+        /// a soft input method, so it will be Z-ordered and positioned
+        /// independently of any active input method (typically this means it
+        /// gets Z-ordered on top of the input method, so it can use the full
+        /// screen for its content and cover the input method if needed.  You
+        /// can use [`Self::ALT_FOCUSABLE_IM`] to modify this
+        /// behavior.
+        const NOT_FOCUSABLE = 0x00000008;
+
+        /// This window can never receive touch events.
+        const NOT_TOUCHABLE = 0x00000010;
+
+        /// Even when this window is focusable (if
+        /// [`Self::NOT_FOCUSABLE`] is not set), allow any pointer
+        /// events outside of the window to be sent to the windows behind it.
+        /// Otherwise it will consume all pointer events itself, regardless of
+        /// whether they are inside of the window.
+        const NOT_TOUCH_MODAL = 0x00000020;
+
+        /// When set, if the device is asleep when the touch
+        /// screen is pressed, you will receive this first touch event.  Usually
+        /// the first touch event is consumed by the system since the user can
+        /// not see what they are pressing on.
+        #[deprecated]
+        const TOUCHABLE_WHEN_WAKING = 0x00000040;
+
+        /// As long as this window is visible to the user, keep
+        /// the device's screen turned on and bright.
+        const KEEP_SCREEN_ON = 0x00000080;
+
+        /// Place the window within the entire screen, ignoring
+        /// decorations around the border (such as the status bar).  The
+        /// window must correctly position its contents to take the screen
+        /// decoration into account.
+        const LAYOUT_IN_SCREEN = 0x00000100;
+
+        /// Allows the window to extend outside of the screen.
+        const LAYOUT_NO_LIMITS = 0x00000200;
+
+        /// 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
+        /// [`Self::SOFT_INPUT_ADJUST_RESIZE`] the window will stay
+        /// fullscreen and will not resize.
+        const FULLSCREEN = 0x00000400;
+
+        /// Override [`Self::FULLSCREEN`] and force the
+        /// screen decorations (such as the status bar) to be shown.
+        const FORCE_NOT_FULLSCREEN = 0x00000800;
+        /// Turn on dithering when compositing this window to
+        /// the screen.
+        #[deprecated="This flag is no longer used"]
+        const DITHER = 0x00001000;
+
+        /// Treat the content of the window as secure, preventing
+        /// it from appearing in screenshots or from being viewed on non-secure
+        /// displays.
+        const SECURE = 0x00002000;
+
+        /// A special mode where the layout parameters are used
+        /// to perform scaling of the surface when it is composited to the
+        /// screen.
+        const SCALED = 0x00004000;
+
+        /// Intended for windows that will often be used when the user is
+        /// holding the screen against their face, it will aggressively
+        /// filter the event stream to prevent unintended presses in this
+        /// situation that may not be desired for a particular window, when
+        /// such an event stream is detected, the application will receive
+        /// a `AMOTION_EVENT_ACTION_CANCEL` to indicate this so
+        /// applications can handle this accordingly by taking no action on
+        /// the event until the finger is released.
+        const IGNORE_CHEEK_PRESSES = 0x00008000;
+
+        /// A special option only for use in combination with
+        /// [`Self::LAYOUT_IN_SCREEN`].  When requesting layout in
+        /// the screen your window may appear on top of or behind screen decorations
+        /// such as the status bar.  By also including this flag, the window
+        /// manager will report the inset rectangle needed to ensure your
+        /// content is not covered by screen decorations.
+        const LAYOUT_INSET_DECOR = 0x00010000;
+
+        /// Invert the state of [`Self::NOT_FOCUSABLE`] with
+        /// respect to how this window interacts with the current method.
+        /// That is, if [`Self::NOT_FOCUSABLE`] is set and this flag is set,
+        /// then the window will behave as if it needs to interact with the
+        /// input method and thus be placed behind/away from it; if
+        /// [`Self::NOT_FOCUSABLE`] is not set and this flag is set,
+        /// then the window will behave as if it doesn't need to interact
+        /// with the input method and can be placed to use more space and
+        /// cover the input method.
+        const ALT_FOCUSABLE_IM = 0x00020000;
+
+        /// If you have set [`Self::NOT_TOUCH_MODAL`], you
+        /// can set this flag to receive a single special MotionEvent with
+        /// the action
+        /// `AMOTION_EVENT_ACTION_OUTSIDE` for
+        /// touches that occur outside of your window.  Note that you will not
+        /// receive the full down/move/up gesture, only the location of the
+        /// first down as an `AMOTION_EVENT_ACTION_OUTSIDE`.
+        const WATCH_OUTSIDE_TOUCH = 0x00040000;
+
+        /// Special flag to let windows be shown when the screen
+        /// is locked. This will let application windows take precedence over
+        /// key guard or any other lock screens. Can be used with
+        /// [`Self::KEEP_SCREEN_ON`] to turn screen on and display
+        /// windows directly before showing the key guard window.  Can be used with
+        /// [`Self::DISMISS_KEYGUARD`] to automatically fully
+        /// dismiss non-secure key guards.  This flag only applies to the top-most
+        /// full-screen window.
+        const SHOW_WHEN_LOCKED = 0x00080000;
+
+        /// Ask that the system wallpaper be shown behind
+        /// your window.  The window surface must be translucent to be able
+        /// to actually see the wallpaper behind it; this flag just ensures
+        /// that the wallpaper surface will be there if this window actually
+        /// has translucent regions.
+        const SHOW_WALLPAPER = 0x00100000;
+
+        /// When set as a window is being added or made
+        /// visible, once the window has been shown then the system will
+        /// poke the power manager's user activity (as if the user had woken
+        /// up the device) to turn the screen on.
+        const TURN_SCREEN_ON = 0x00200000;
+
+        /// When set the window will cause the key guard to
+        /// be dismissed, only if it is not a secure lock key guard.  Because such
+        /// a key guard is not needed for security, it will never re-appear if
+        /// the user navigates to another window (in contrast to
+        /// [`Self::SHOW_WHEN_LOCKED`], which will only temporarily
+        /// hide both secure and non-secure key guards but ensure they reappear
+        /// when the user moves to another UI that doesn't hide them).
+        /// If the key guard is currently active and is secure (requires an
+        /// unlock pattern) then the user will still need to confirm it before
+        /// seeing this window, unless [`Self::SHOW_WHEN_LOCKED`] has
+        /// also been set.
+        const DISMISS_KEYGUARD = 0x00400000;
+    }
+}
+
 #[derive(Debug, Clone)]
 pub struct AndroidApp {
     pub(crate) inner: Arc<RwLock<AndroidAppInner>>,
@@ -251,6 +418,26 @@ impl AndroidApp {
         self.inner.read().unwrap().asset_manager()
     }
 
+    /// Change the window flags of the given activity.
+    ///
+    /// Note that some flags must be set before the window decoration is created,
+    /// see
+    /// `<https://developer.android.com/reference/android/view/Window#setFlags(int,%20int)>`.
+    pub fn set_window_flags(
+        &self,
+        add_flags: WindowManagerFlags,
+        remove_flags: WindowManagerFlags,
+    ) {
+        self.inner
+            .write()
+            .unwrap()
+            .set_window_flags(add_flags, remove_flags);
+    }
+
+    /// Enable additional input axis
+    ///
+    /// To reduce overhead, by default only [`input::Axis::X`] and [`input::Axis::Y`] are enabled
+    /// and other axis should be enabled explicitly.
     pub fn enable_motion_axis(&self, axis: input::Axis) {
         self.inner.write().unwrap().enable_motion_axis(axis);
     }
@@ -259,6 +446,15 @@ impl AndroidApp {
         self.inner.write().unwrap().disable_motion_axis(axis);
     }
 
+    /// Query and process all out-standing input event
+    ///
+    /// Applications are generally either expected to call this in-sync with their rendering or
+    /// in response to a [`MainEvent::InputAvailable`] event being delivered. _Note though that your
+    /// application is will only be delivered a single [`MainEvent::InputAvailable`] event between calls
+    /// to this API._
+    ///
+    /// To reduce overhead, by default only [`input::Axis::X`] and [`input::Axis::Y`] are enabled
+    /// and other axis should be enabled explicitly via [`Self::enable_motion_axis`].
     pub fn input_events<'b, F>(&self, callback: F)
     where
         F: FnMut(&input::InputEvent),

android-activity/src/native_activity/mod.rs

@@ -21,7 +21,7 @@ use ndk::configuration::Configuration;
 use ndk::input_queue::InputQueue;
 use ndk::native_window::NativeWindow;
 
-use crate::{util, AndroidApp, ConfigurationRef, MainEvent, PollEvent, Rect};
+use crate::{util, AndroidApp, ConfigurationRef, MainEvent, PollEvent, Rect, WindowManagerFlags};
 
 mod ffi;
 
@@ -353,6 +353,22 @@ impl AndroidAppInner {
         }
     }
 
+    pub fn set_window_flags(
+        &self,
+        add_flags: WindowManagerFlags,
+        remove_flags: WindowManagerFlags,
+    ) {
+        let na = self.native_activity();
+        let na_mut = na as *mut ndk_sys::ANativeActivity;
+        unsafe {
+            ffi::ANativeActivity_setWindowFlags(
+                na_mut.cast(),
+                add_flags.bits(),
+                remove_flags.bits(),
+            );
+        }
+    }
+
     pub fn enable_motion_axis(&self, _axis: input::Axis) {
         // NOP - The InputQueue API doesn't let us optimize which axis values are read
     }