# Pinch ~~~ package io.appium.android.bootstrap.handler; import com.android.uiautomator.core.UiObjectNotFoundException; import io.appium.android.bootstrap.*; import org.json.JSONException; import java.util.Hashtable; /** * This handler is used to pinch in/out elements in the Android UI. * * Based on the element Id, pinch in/out that element. * */ public class Pinch extends CommandHandler { /* * @param command The {@link AndroidCommand} used for this handler. * * @return {@link AndroidCommandResult} * * @throws JSONException * * @see io.appium.android.bootstrap.CommandHandler#execute(io.appium.android. * bootstrap.AndroidCommand) */ @Override public AndroidCommandResult execute(final AndroidCommand command) throws JSONException { final Hashtable<String, Object> params = command.params(); AndroidElement el; final String direction = params.get("direction").toString(); final Integer percent = (Integer) params.get("percent"); final Integer steps = (Integer) params.get("steps"); try { el = command.getElement(); if (el == null) { return getErrorResult("Could not find an element with elementId: " + params.get("elementId")); } } catch (final Exception e) { // JSONException, NullPointerException, etc. return getErrorResult("Unknown error:" + e.getMessage()); } Logger.debug("Pinching " + direction + " " + percent.toString() + "%" + " with steps: " + steps.toString()); boolean res; if (direction.equals("in")) { try { res = el.pinchIn(percent, steps); } catch (final UiObjectNotFoundException e) { return getErrorResult("Selector could not be matched to any UI element displayed"); } } else { try { res = el.pinchOut(percent, steps); } catch (final UiObjectNotFoundException e) { return getErrorResult("Selector could not be matched to any UI element displayed"); } } if (res) { return getSuccessResult(res); } else { return getErrorResult("Pinch did not complete successfully"); } } } ~~~ 了解2个概念：pinchIn和pinchOut。  2个手指同时按住A和B，同时将A滑向A1,B滑向B1，称为pinchIn 2个手指同时按住A1和B1，同时将A1滑向A，B1滑向B，成为pinchOut. 那么Pinch类就是接受这一指令的，传入的参数有方向direction，percent代表滑到对角线百分之几停止，steps代表滑到时间，一个step代表5毫秒。根据direction来判断是调用UiObject.pinchIn和UiObject.pinchOut.