fix KeepSplitScreenRatio keeping 100%/0% split after dragging to close

Author: programminghoch10

KeepSplitScreenRatio/src/main/java/com/programminghoch10/KeepSplitScreenRatio/Hook.kt

@@ -2,26 +2,91 @@ package com.programminghoch10.KeepSplitScreenRatio
 
 import android.os.IBinder
 import de.robv.android.xposed.IXposedHookLoadPackage
+import de.robv.android.xposed.XC_MethodReplacement
+import de.robv.android.xposed.XposedBridge
 import de.robv.android.xposed.XposedHelpers
 import de.robv.android.xposed.callbacks.XC_LoadPackage
 import de.robv.android.xposed.XC_MethodHook as MethodHook
 
+
 class Hook : IXposedHookLoadPackage {
 
     override fun handleLoadPackage(lpparam: XC_LoadPackage.LoadPackageParam) {
         if (lpparam.packageName != "com.android.systemui") return
 
-        val SplitScreenTransitionsClass = XposedHelpers.findClass("com.android.wm.shell.splitscreen.SplitScreenTransitions", lpparam.classLoader)
+        val SplitLayoutClass = XposedHelpers.findClass("com.android.wm.shell.common.split.SplitLayout", lpparam.classLoader)
+        val StageCoordinatorClass = XposedHelpers.findClass("com.android.wm.shell.splitscreen.StageCoordinator", lpparam.classLoader)
+        
+        /*
+        Currently this module disables SplitScreen enter and dismiss animations completely.
+        
+        Before animating, the Divider state is initialized in 
+        https://github.com/LineageOS/android_frameworks_base/blob/2dc97cf3d6234c87497ca78b2734bb3ed604c349/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java#L1849
+        then a "fling to center" is started in
+        https://github.com/LineageOS/android_frameworks_base/blob/2dc97cf3d6234c87497ca78b2734bb3ed604c349/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java#L3586
+        Since this "fling to center" is embedded deeply, 
+        we currently simply disable it.
+        */
+        
         XposedHelpers.findAndHookMethod(
-            SplitScreenTransitionsClass,
-            "setEnterTransition",
-            IBinder::class.java,
-            "android.window.RemoteTransition",
+            StageCoordinatorClass,
+            "onSnappedToDismiss",
             Int::class.java,
             Boolean::class.java,
+            object : MethodHook() {
+                override fun afterHookedMethod(param: MethodHookParam) {
+                    // reset the divider position after a fling to dismiss is finished,
+                    // since the SplitScreen enter animation won't take care of it anymore
+                    val mSplitLayout = XposedHelpers.getObjectField(param.thisObject, "mSplitLayout")
+                    //XposedHelpers.callMethod(mSplitLayout, "resetDividerPosition")
+                    XposedBridge.invokeOriginalMethod(
+                        XposedHelpers.findMethodExact(
+                            SplitLayoutClass,
+                            "resetDividerPosition",
+                            *arrayOf<Any>(),
+                        ),
+                        mSplitLayout,
+                        arrayOf(),
+                    )
+                }
+            },
+        )
+        
+        // disable resetDividerPosition entirely
+        XposedHelpers.findAndHookMethod(
+            SplitLayoutClass,
+            "resetDividerPosition",
+            XC_MethodReplacement.DO_NOTHING,
+        )
+        
+        XposedHelpers.findAndHookMethod(
+            StageCoordinatorClass,
+            "prepareSplitLayout",
+            "android.window.WindowContainerTransaction",
+            Boolean::class.java,
+            object : MethodHook() {
+                override fun beforeHookedMethod(param: MethodHookParam) {
+                    // disabling resizeAnim makes the method call resetDividerPosition()
+                    param.args[1] = false
+                }
+            },
+        )
+        
+        val startPendingAnimationMethod =
+            StageCoordinatorClass.declaredMethods.find { it.name == "startPendingAnimation" && it.parameterTypes[0] == IBinder::class.java }!!
+        XposedBridge.hookMethod(
+            startPendingAnimationMethod,
             object : MethodHook() {
                 override fun beforeHookedMethod(param: MethodHookParam) {
-                    param.args[3] = false
+                    val binder = param.args[0] as IBinder
+                    val stageCoordinator = param.thisObject
+                    val mSplitTransitions = XposedHelpers.getObjectField(stageCoordinator, "mSplitTransitions")
+                    val isPendingEnter = XposedHelpers.callMethod(mSplitTransitions, "isPendingEnter", binder) as Boolean
+                    if (!isPendingEnter) return
+                    val mPendingEnter = XposedHelpers.getObjectField(mSplitTransitions, "mPendingEnter")
+                    XposedHelpers.getBooleanField(mPendingEnter, "mResizeAnim")
+                    // disable resizeAnim when entering SplitScreen
+                    XposedHelpers.setBooleanField(mPendingEnter, "mResizeAnim", false)
                 }
             },
         )