## iOS 'mobile:': 元素查找滑动 使用下列方式查找元素或滚动视图： - 使用元素id并指定<code>name</code>参数 - 或使用<code>predicateString</code>参数指定NSPredicate的值 NSPredicate示例参考 [这里](../../ios/ios-predicate.md) 另外， [https://kapeli.com/cheat_sheets/NSPredicate.docset/Contents/Resources/Documents/index](https://kapeli.com/cheat_sheets/NSPredicate.docset/Contents/Resources/Documents/index) 是一个很好的NSPredicate备忘表。 NSPredicate 定位元素时使用 'name == accessibilityIdentifier'断言参数 ```java String pre = "label == 'exact_text'"; MobileElement el = (MobileElement) driver.findElement(MobileBy.id("element_id")); mobileScrollToElementIOS(el, pre); /** * Performs element scroll by predicate string * * @param el the element to scroll * @param pre the predicate string * @version java-client: 7.3.0 **/ public void mobileScrollToElementIOS(MobileElement el, String pre) { System.out.println("mobileScrollToElementIOS(): pre: '" + pre + "'"); // always log your actions // Animation default time: // - iOS: 200 ms // final value depends on your app and could be greater final int ANIMATION_TIME = 200; // ms final HashMap<String, String> scrollObject = new HashMap<String, String>(); scrollObject.put("element", el.getId()); scrollObject.put("predicateString", pre); try { driver.executeScript("mobile:scroll", scrollObject); Thread.sleep(ANIMATION_TIME); // always allow swipe action to complete } catch (Exception e) { System.err.println("mobileScrollToElementIOS(): FAILED\n" + e.getMessage()); return; } } ``` 'mobileScrollToElementIOS'不能可靠地工作并且在滚动时经常缺少必要的元素，在复杂页面尤其如此。有时将<code>simpleIsVisibleCheck'</code>设置为true也许有帮助。 作为临时方案，可以尝试组合使用简单滚动(屏幕级别或元素级别)并在每一次滚动后检查期望的元素是否在屏幕上可见。 以下为这种组合方式的使用示例： ```java String pre = "label == 'exact_text'"; mobileScrollScreenByPredicateIOS(pre, Direction.DOWN); /** * Performs screen scroll by predicate string * * @param pre the predicate string * @param dir the direction of swipe * @version java-client: 7.3.0 **/ public void mobileScrollScreenByPredicateIOS(String pre, Direction dir) { System.out.println("mobileScrollScreenByPredicateIOS(): dir: '" + dir + "'"); // always log your actions final int MAX_SWIPES = 5; // limit maximum swipes for (int i = 0; i < MAX_SWIPES; i++) { try { if (driver.findElement(MobileBy.iOSNsPredicateString(pre)).isDisplayed()) break; } catch (Exception e) { // ignore } mobileScrollScreenIOS(dir); } } ```