触摸事件（旧版）

介绍

¥Introduction

可以通过手动将 TouchEvent 调度到页面来测试处理旧版 触摸事件 以响应滑动、捏合和点击等手势的 Web 应用。以下示例演示了如何使用 locator.dispatchEvent() 并将 触摸 点作为参数传递。

¥Web applications that handle legacy touch events to respond to gestures like swipe, pinch, and tap can be tested by manually dispatching TouchEvents to the page. The examples below demonstrate how to use locator.dispatchEvent() and pass Touch points as arguments.

模拟平移手势

¥Emulating pan gesture

在下面的示例中，我们模拟了预计会移动地图的平移手势。被测应用仅使用触摸点的 clientX/clientY 坐标，因此我们仅初始化它。在更复杂的场景中，如果你的应用需要它们，你可能还需要设置 pageX/pageY/screenX/screenY。

¥In the example below, we emulate pan gesture that is expected to move the map. The app under test only uses clientX/clientY coordinates of the touch point, so we initialize just that. In a more complex scenario you may need to also set pageX/pageY/screenX/screenY, if your app needs them.

import { test, expect, devices, type Locator } from '@playwright/test';

test.use({ ...devices['Pixel 7'] });

async function pan(locator: Locator, deltaX?: number, deltaY?: number, steps?: number) {
  const { centerX, centerY } = await locator.evaluate((target: HTMLElement) => {
    const bounds = target.getBoundingClientRect();
    const centerX = bounds.left + bounds.width / 2;
    const centerY = bounds.top + bounds.height / 2;
    return { centerX, centerY };
  });

  // Providing only clientX and clientY as the app only cares about those.
  const touches = [{
    identifier: 0,
    clientX: centerX,
    clientY: centerY,
  }];
  await locator.dispatchEvent('touchstart',
      { touches, changedTouches: touches, targetTouches: touches });

  steps = steps ?? 5;
  deltaX = deltaX ?? 0;
  deltaY = deltaY ?? 0;
  for (let i = 1; i <= steps; i++) {
    const touches = [{
      identifier: 0,
      clientX: centerX + deltaX * i / steps,
      clientY: centerY + deltaY * i / steps,
    }];
    await locator.dispatchEvent('touchmove',
        { touches, changedTouches: touches, targetTouches: touches });
  }

  await locator.dispatchEvent('touchend');
}

test(`pan gesture to move the map`, async ({ page }) => {
  await page.goto('https://www.google.com/maps/place/@37.4117722,-122.0713234,15z',
      { waitUntil: 'commit' });
  await page.getByRole('button', { name: 'Keep using web' }).click();
  await expect(page.getByRole('button', { name: 'Keep using web' })).not.toBeVisible();
  // Get the map element.
  const met = page.locator('[data-test-id="met"]');
  for (let i = 0; i < 5; i++)
    await pan(met, 200, 100);
  // Ensure the map has been moved.
  await expect(met).toHaveScreenshot();
});

模拟捏合手势

¥Emulating pinch gesture

在下面的示例中，我们模拟了捏合手势，即两个触摸点彼此靠近。预计会缩小地图。被测应用仅使用触摸点的 clientX/clientY 坐标，因此我们仅初始化它。在更复杂的场景中，如果你的应用需要它们，你可能还需要设置 pageX/pageY/screenX/screenY。

¥In the example below, we emulate pinch gesture, i.e. two touch points moving closer to each other. It is expected to zoom out the map. The app under test only uses clientX/clientY coordinates of touch points, so we initialize just that. In a more complex scenario you may need to also set pageX/pageY/screenX/screenY, if your app needs them.

import { test, expect, devices, type Locator } from '@playwright/test';

test.use({ ...devices['Pixel 7'] });

async function pinch(locator: Locator,
  arg: { deltaX?: number, deltaY?: number, steps?: number, direction?: 'in' | 'out' }) {
  const { centerX, centerY } = await locator.evaluate((target: HTMLElement) => {
    const bounds = target.getBoundingClientRect();
    const centerX = bounds.left + bounds.width / 2;
    const centerY = bounds.top + bounds.height / 2;
    return { centerX, centerY };
  });

  const deltaX = arg.deltaX ?? 50;
  const steps = arg.steps ?? 5;
  const stepDeltaX = deltaX / (steps + 1);

  // Two touch points equally distant from the center of the element.
  const touches = [
    {
      identifier: 0,
      clientX: centerX - (arg.direction === 'in' ? deltaX : stepDeltaX),
      clientY: centerY,
    },
    {
      identifier: 1,
      clientX: centerX + (arg.direction === 'in' ? deltaX : stepDeltaX),
      clientY: centerY,
    },
  ];
  await locator.dispatchEvent('touchstart',
      { touches, changedTouches: touches, targetTouches: touches });

  // Move the touch points towards or away from each other.
  for (let i = 1; i <= steps; i++) {
    const offset = (arg.direction === 'in' ? (deltaX - i * stepDeltaX) : (stepDeltaX * (i + 1)));
    const touches = [
      {
        identifier: 0,
        clientX: centerX - offset,
        clientY: centerY,
      },
      {
        identifier: 0,
        clientX: centerX + offset,
        clientY: centerY,
      },
    ];
    await locator.dispatchEvent('touchmove',
        { touches, changedTouches: touches, targetTouches: touches });
  }

  await locator.dispatchEvent('touchend', { touches: [], changedTouches: [], targetTouches: [] });
}

test(`pinch in gesture to zoom out the map`, async ({ page }) => {
  await page.goto('https://www.google.com/maps/place/@37.4117722,-122.0713234,15z',
      { waitUntil: 'commit' });
  await page.getByRole('button', { name: 'Keep using web' }).click();
  await expect(page.getByRole('button', { name: 'Keep using web' })).not.toBeVisible();
  // Get the map element.
  const met = page.locator('[data-test-id="met"]');
  for (let i = 0; i < 5; i++)
    await pinch(met, { deltaX: 40, direction: 'in' });
  // Ensure the map has been zoomed out.
  await expect(met).toHaveScreenshot();
});