energy monitor example fails to run on Android 12

[matthewjrichey]

Slint release tested: 1.6.0

Command used to build example:
cargo apk build -p energy-monitor --target x86_64-linux-android --lib

Executed on emulated Android 12 (x86_64) and actual Android 12 device (aarch64).

Failure (captured with adb logcat):

04-06 16:02:03.957  2487  2487 W NativeActivity: NativeActivity LoadNativeLibrary("/data/app/~~loKhCe5jYqQSlyBRQqAc3w==/rust.energy_monitor-4pE9Ttt1jr8x3B5BrjazKQ==/lib/x86_64/libenergy_monitor.so") failed: dlopen failed: cannot locate symbol "AMotionEvent_getActionButton" referenced by "/data/app/~~loKhCe5jYqQSlyBRQqAc3w==/rust.energy_monitor-4pE9Ttt1jr8x3B5BrjazKQ==/lib/x86_64/libenergy_monitor.so"...
04-06 16:02:03.958  2487  2487 D AndroidRuntime: Shutting down VM
04-06 16:02:03.959  2487  2487 E AndroidRuntime: FATAL EXCEPTION: main
04-06 16:02:03.959  2487  2487 E AndroidRuntime: Process: rust.energy_monitor, PID: 2487
04-06 16:02:03.959  2487  2487 E AndroidRuntime: java.lang.UnsatisfiedLinkError: Unable to load native library "/data/app/~~loKhCe5jYqQSlyBRQqAc3w==/rust.energy_monitor-4pE9Ttt1jr8x3B5BrjazKQ==/lib/x86_64/libenergy_monitor.so": dlopen failed: cannot locate symbol "AMotionEvent_getActionButton" referenced by "/data/app/~~loKhCe5jYqQSlyBRQqAc3w==/rust.energy_monitor-4pE9Ttt1jr8x3B5BrjazKQ==/lib/x86_64/libenergy_monitor.so"...
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.NativeActivity.onCreate(NativeActivity.java:178)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.Activity.performCreate(Activity.java:7994)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.Activity.performCreate(Activity.java:7978)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:106)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:223)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:7656)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
04-06 16:02:03.959  2487  2487 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Researched and discovered that AMotionEvent_getActionButton is only available on Android NDK 33 (Android 13) or higher. I came up with a working fix for the problem, which is tested and working on Android 12. I will file the fix as a PR.

[matthewjrichey]

As a random member of the public, I do not have push access to this public repository (which is understandable), so I could not create a pull request.

Here is a diff that captures my fix for the issue.

diff --git a/internal/backends/android-activity/androidwindowadapter.rs b/internal/backends/android-activity/androidwindowadapter.rs
index 10e98dff8..ff26cd9ea 100644
--- a/internal/backends/android-activity/androidwindowadapter.rs
+++ b/internal/backends/android-activity/androidwindowadapter.rs
@@ -3,7 +3,9 @@
 
 use super::*;
 use crate::javahelper::{print_jni_error, JavaHelper};
-use android_activity::input::{InputEvent, KeyAction, Keycode, MotionAction, MotionEvent};
+use android_activity::input::{
+    ButtonState, InputEvent, KeyAction, Keycode, MotionAction, MotionEvent,
+};
 use android_activity::{InputStatus, MainEvent, PollEvent};
 use i_slint_core::api::{LogicalPosition, PhysicalPosition, PhysicalSize, PlatformError, Window};
 use i_slint_core::items::ColorScheme;
@@ -40,6 +42,7 @@ pub struct AndroidWindowAdapter {
     pub(crate) show_cursor_handles: Cell<bool>,
 
     long_press: RefCell<Option<LongPressDetection>>,
+    last_pressed_state: Cell<ButtonState>,
 }
 
 impl WindowAdapter for AndroidWindowAdapter {
@@ -187,6 +190,7 @@ pub fn new(app: AndroidApp) -> Rc<Self> {
             offset: Default::default(),
             show_cursor_handles: Cell::new(false),
             long_press: RefCell::default(),
+            last_pressed_state: Cell::new(ButtonState(0)),
         })
     }
 
@@ -281,7 +285,7 @@ fn process_inputs(&self) -> Result<(), android_activity::error::AppError> {
                         self.window.dispatch_event(WindowEvent::PointerPressed {
                             position: position_for_event(motion_event, self.offset.get())
                                 .to_logical(self.window.scale_factor()),
-                            button: button_for_event(motion_event),
+                            button: button_for_event(motion_event, &self.last_pressed_state),
                         });
                         InputStatus::Handled
                     }
@@ -308,7 +312,7 @@ fn process_inputs(&self) -> Result<(), android_activity::error::AppError> {
                         self.window.dispatch_event(WindowEvent::PointerReleased {
                             position: position_for_event(motion_event, self.offset.get())
                                 .to_logical(self.window.scale_factor()),
-                            button: button_for_event(motion_event),
+                            button: button_for_event(motion_event, &self.last_pressed_state),
                         });
                         InputStatus::Handled
                     }
@@ -456,13 +460,51 @@ fn position_for_event(motion_event: &MotionEvent, offset: PhysicalPosition) -> P
     })
 }
 
-fn button_for_event(motion_event: &MotionEvent) -> PointerEventButton {
-    match motion_event.action_button() {
-        android_activity::input::Button::Primary => PointerEventButton::Left,
-        android_activity::input::Button::Secondary => PointerEventButton::Right,
-        android_activity::input::Button::Tertiary => PointerEventButton::Middle,
-        _ => PointerEventButton::Other,
+fn button_for_event(
+    motion_event: &MotionEvent,
+    last_pressed_cell: &Cell<ButtonState>,
+) -> PointerEventButton {
+    //
+    // The motion_event API has a method called action_button() which can be used to directly
+    // determine the button associated with the event. However, the disadvantage of using the
+    // action_button() API is that it relies on NDK 33 or higher, which implies that the output
+    // application will only run on Android 13 or higher.
+    //
+    // This functionally equivalent method of computing the action button relies on the
+    // button_state() call from the motion event, rather than action_button(). It is a bit more
+    // complex than using action_button() directly, since the previous button state must be
+    // tracked and used in the calculation for computing which button was toggled. However, this
+    // will run on Android 12 (and possibly lower).
+    //
+    // See here for further discussion:
+    //
+    // https://stackoverflow.com/questions/75718566/amotionevent-getbuttonstate-returns-0-for-every-button-during-mouse-button-relea
+    //
+    let cur_pressed_state = motion_event.button_state();
+    let last_pressed_state = last_pressed_cell.get();
+    let toggled = match motion_event.action() {
+        MotionAction::ButtonPress => {
+            last_pressed_cell.set(cur_pressed_state);
+            ButtonState((last_pressed_state.0 ^ cur_pressed_state.0) & cur_pressed_state.0)
+        }
+        MotionAction::ButtonRelease => {
+            last_pressed_cell.set(cur_pressed_state);
+            ButtonState((last_pressed_state.0 ^ cur_pressed_state.0) & last_pressed_state.0)
+        }
+        _ => ButtonState(0),
+    };
+
+    // if multiple buttons toggled, primary takes precedence, then secondary, etc.
+    if toggled.primary() {
+        return PointerEventButton::Left;
+    }
+    if toggled.secondary() {
+        return PointerEventButton::Right;
+    }
+    if toggled.teriary() {
+        return PointerEventButton::Middle;
     }
+    return PointerEventButton::Other;
 }
 
 fn map_key_event(key_event: &android_activity::input::KeyEvent) -> Option<WindowEvent> {

[hunger]

I took the liberty to turn this diff into a PR here: #5047 for your review-conveninece.

The code looks sensible to me, but I have no Android setup here (nor a Android 12 device) to test this with.

@matthewjrichey: You can clone the repo, push your code into your own clone and then create a PR from that. This approach is not limited to Slint, it works for any project on github, just in case you run into the situation again.

[hunger]

Thank you for your time and contribution. I think this is small enough to count as a "simple fix" and not need the full CLA dance, which my PR goes around...