新增 设置 - 显示通知重要程度

此功能为 AOSP 通知的标准功能，从 MIUI 12 开始被隐藏
请参见：
- https://developer.android.com/guide/topics/ui/notifiers/notifications?hl=zh-cn#importance
- https://www.coolapk.com/feed/24638207?shareKey=YzcwZGMzNzM2NWQ3NjIyOTU4NzY~

app/src/main/java/com/lt2333/simplicitytools/hook/MainHook.kt

@@ -39,6 +39,10 @@ class MainHook : IXposedHookLoadPackage {
                 "com.android.updater" -> {
                     Updater().handleLoadPackage(lpparam)
                 }
+                //设置
+                "com.android.settings" -> {
+                    Settings().handleLoadPackage(lpparam)
+                }
             }
         }
     }

app/src/main/java/com/lt2333/simplicitytools/hook/app/Settings.kt

@@ -0,0 +1,11 @@
+package com.lt2333.simplicitytools.hook.app
+
+import com.lt2333.simplicitytools.hook.app.settings.ShowNotificationImportance
+import de.robv.android.xposed.IXposedHookLoadPackage
+import de.robv.android.xposed.callbacks.XC_LoadPackage
+
+class Settings: IXposedHookLoadPackage {
+    override fun handleLoadPackage(lpparam: XC_LoadPackage.LoadPackageParam) {
+        ShowNotificationImportance().handleLoadPackage(lpparam)
+    }
+}

app/src/main/java/com/lt2333/simplicitytools/hook/app/settings/ShowNotificationImportance.kt

@@ -0,0 +1,73 @@
+package com.lt2333.simplicitytools.hook.app.settings
+
+import android.app.NotificationChannel
+import com.lt2333.simplicitytools.util.XSPUtils
+import de.robv.android.xposed.IXposedHookLoadPackage
+import de.robv.android.xposed.XC_MethodHook
+import de.robv.android.xposed.XposedHelpers
+import de.robv.android.xposed.callbacks.XC_LoadPackage
+
+class ShowNotificationImportance: IXposedHookLoadPackage {
+    override fun handleLoadPackage(lpparam: XC_LoadPackage.LoadPackageParam) {
+        if (!XSPUtils.getBoolean("show_notification_importance", false)) return
+
+        val channelNotificationSettingsClass = XposedHelpers.findClass(
+            "com.android.settings.notification.ChannelNotificationSettings",
+            lpparam.classLoader
+        )
+
+        XposedHelpers.findAndHookMethod(channelNotificationSettingsClass, "removeDefaultPrefs",
+            object : XC_MethodHook() {
+            override fun beforeHookedMethod(param: MethodHookParam) {
+                val importance =
+                    XposedHelpers.callMethod(param.thisObject, "findPreference", "importance")
+                val mChannel =
+                    XposedHelpers.getObjectField(param.thisObject, "mChannel") as NotificationChannel
+                val index = XposedHelpers.callMethod(
+                    importance,
+                    "findSpinnerIndexOfValue",
+                    mChannel.importance.toString()
+                ) as Int
+                if (index < 0) return@beforeHookedMethod
+
+                XposedHelpers.callMethod(importance, "setValueIndex", index)
+
+                XposedHelpers.setAdditionalInstanceField(
+                    importance,
+                    "channelNotificationSettings",
+                    param.thisObject
+                )
+
+                param.result = null
+            }
+        })
+
+        val dropDownPreferenceClass = XposedHelpers.findClass(
+            "androidx.preference.Preference",
+            lpparam.classLoader
+        )
+
+        XposedHelpers.findAndHookMethod(dropDownPreferenceClass, "callChangeListener",
+            Any::class.java, object : XC_MethodHook() {
+            override fun afterHookedMethod(param: MethodHookParam) {
+                val channelNotificationSettings = XposedHelpers.getAdditionalInstanceField(
+                    param.thisObject,
+                    "channelNotificationSettings"
+                )
+                    ?: return@afterHookedMethod
+
+                val mChannel = XposedHelpers.getObjectField(
+                    channelNotificationSettings,
+                    "mChannel"
+                ) as NotificationChannel
+                XposedHelpers.callMethod(mChannel, "setImportance", (param.args[0] as String).toInt())
+
+                val mBackend = XposedHelpers.getObjectField(channelNotificationSettings, "mBackend")
+                val mPkg =
+                    XposedHelpers.getObjectField(channelNotificationSettings, "mPkg") as String
+                val mUid = XposedHelpers.getObjectField(channelNotificationSettings, "mUid") as Int
+                XposedHelpers.callMethod(mBackend, "updateChannel", mPkg, mUid, mChannel)
+            }
+        })
+    }
+}