修正：如果是unity申请悬浮权限，当权限设置页面打开时，app切换到后台再切回，设置页面会被强制关闭，此时正常流程不会触发

Author: githubsdk

lib/utilcode/src/main/java/com/blankj/utilcode/util/PermissionUtils.java

@@ -368,6 +368,8 @@ static final class PermissionActivityImpl extends UtilsTransActivity.TransActivi
         private static final int    TYPE_WRITE_SETTINGS = 0x02;
         private static final int    TYPE_DRAW_OVERLAYS  = 0x03;
 
+        private static int currentRequestCode = -1;
+
         private static PermissionActivityImpl INSTANCE = new PermissionActivityImpl();
 
         public static void start(final int type) {
@@ -403,8 +405,10 @@ public void run() {
                 }
                 requestPermissions(activity);
             } else if (type == TYPE_WRITE_SETTINGS) {
+                currentRequestCode = TYPE_WRITE_SETTINGS;
                 startWriteSettingsActivity(activity, TYPE_WRITE_SETTINGS);
             } else if (type == TYPE_DRAW_OVERLAYS) {
+                currentRequestCode = TYPE_DRAW_OVERLAYS;
                 startOverlayPermissionActivity(activity, TYPE_DRAW_OVERLAYS);
             } else {
                 activity.finish();
@@ -441,8 +445,22 @@ public boolean dispatchTouchEvent(UtilsTransActivity activity, MotionEvent ev) {
             return true;
         }
 
+        @Override
+        public void onDestroy(final UtilsTransActivity activity) {
+            //如果是unity调用，app从后台切回，当前activity会被强制关闭，此时正常流程不会触发，所以在这里检测
+            if (currentRequestCode != -1) {
+                checkRequestCallback(currentRequestCode);
+                currentRequestCode = -1;
+            }
+            super.onDestroy(activity);
+        }
+
         @Override
         public void onActivityResult(UtilsTransActivity activity, int requestCode, int resultCode, Intent data) {
+            activity.finish();
+        }
+
+        private void checkRequestCallback(int requestCode) {
             if (requestCode == TYPE_WRITE_SETTINGS) {
                 if (sSimpleCallback4WriteSettings == null) return;
                 if (isGrantedWriteSettings()) {
@@ -465,7 +483,6 @@ public void run() {
                     }
                 }, 100);
             }
-            activity.finish();
         }
     }