!4898 add setShowOnLockScreen api docs

Merge pull request !4898 from qianlf/master

zh-cn/application-dev/reference/apis/js-apis-window.md

@@ -2470,4 +2470,30 @@ off(eventType: 'windowStageEvent', callback?: Callback<WindowStageEventType&g
           windowStage.off(type);
       }
   }
-  ```
\ No newline at end of file
+  ```
+
+### setShowOnLockScreen('showOnLockScreen')<sup>9+</sup>
+
+setShowOnLockScreen(showOnLockScreen: boolean): void
+
+设置应用显示在锁屏之上。
+
+**系统能力：** SystemCapability.WindowManager.WindowManager.Core
+
+**参数：** 
+
+| 参数名           | 类型    | 必填 | 说明                         |
+| ---------------- | ------- | ---- | ---------------------------- |
+| showOnLockScreen | boolean | 是   | 是否设置应用显示在锁屏之上。 |
+
+**示例：** 
+
+```ts
+class myAbility extends Ability {
+    onWindowStageCreate(windowStage) {
+        console.log('onWindowStageCreate');
+        windowStage.setShowOnLockScreen(true);
+    }
+}
+```
+