Taro.onKeyboardHeightChange(res => { console.log(res.height) }) 使用方法

`Taro.onKeyboardHeightChange` 是 Taro (微信小程序) 提供的一个事件监听器，用于处理当虚拟键盘高度发生改变时触发的回调。这个方法在你需要获取键盘高度变化并对之做出响应的应用场景下非常有用，例如，当用户输入框聚焦并且弹出键盘时，页面布局可能会受到影响，这时可以利用这个事件调整页面布局以保持用户体验。

下面是如何使用它的简单示例：

// 在Page的生命周期钩子或者对应的组件里添加监听
Page({
  mounted() {
    // 注册键盘高度变化的事件处理器
    Taro.onKeyboardHeightChange((res) => {
      // 当键盘高度改变时，console.log 输出新的高度值
      console.log('当前键盘高度:', res.height);
      
      // 这里你可以根据height值动态调整视图的位置或者其他相关的样式
      // 比如说，如果希望底部内容区域随着键盘升起而上移
      this.setData({
        bottomContentY: res.height,
      });
    });
  },
  
  detached() {
    // 销毁时记得移除监听，防止内存泄漏
    Taro.offKeyboardHeightChange();
  }
})

相关问题

import Taro from '@tarojs/taro'; import { Canvas, Button } from '@tarojs/components'; const handleShare = async (text) => { const context = Taro.createCanvasContext('canvas'); const qrCodeBase64 = text; const qrCodeImage = new Taro.Image(); qrCodeImage.src = data:image/png;base64,${qrCodeBase64}; qrCodeImage.onload = async () => { context.drawImage(qrCodeImage, 0, 0, 200, 200, 0, 0, 400, 400); context.draw(false, async () => { const tempFilePath = await Taro.canvasToTempFilePath({ canvasId: 'canvas', fileType: 'jpg', quality: 1, success: (res) => { Taro.showShareImageMenu({ path: res.tempFilePath, success() { console.log('分享成功'); }, fail(err) { console.log('分享失败', err); }, }); }, fail(err) { console.log('canvasToTempFilePath 失败', err); }, }); }); }; }; function SharePage() { const canvasRef = Taro.useRef(); return ( <> <Canvas ref={canvasRef} canvasId="canvas" style={{ width: '400px', height: '400px' }} /> <Button onClick={() => { handleShare('这里填写二维码的 base64 字符串'); }}>分享图片</Button> </> ); } export default SharePage; 代码有报错类型“TaroStatic”上不存在属性“Image”。

这个错误是因为 Taro 框架中没有 Image 类。你需要使用 Taro 的 loadImage 方法来创建一个图片对象，然后将其赋给 Image 对象的 src 属性。修改代码如下：

import Taro from '@tarojs/taro';
import { Canvas, Button } from '@tarojs/components';

const handleShare = async (text) => {
  const context = Taro.createCanvasContext('canvas');
  const qrCodeBase64 = text;
  const qrCodeImage = await Taro.loadImage(`data:image/png;base64,${qrCodeBase64}`);
  context.drawImage(qrCodeImage, 0, 0, 200, 200, 0, 0, 400, 400);
  context.draw(false, async () => {
    const tempFilePath = await Taro.canvasToTempFilePath({
      canvasId: 'canvas',
      fileType: 'jpg',
      quality: 1,
      success: (res) => {
        Taro.showShareImageMenu({
          path: res.tempFilePath,
          success() {
            console.log('分享成功');
          },
          fail(err) {
            console.log('分享失败', err);
          },
        });
      },
      fail(err) {
        console.log('canvasToTempFilePath 失败', err);
      },
    });
  });
};

function SharePage() {
  const canvasRef = Taro.useRef();

  return (
    <>
      <Canvas ref={canvasRef} canvasId="canvas" style={{ width: '400px', height: '400px' }} />
      <Button onClick={() => { handleShare('这里填写二维码的 base64 字符串'); }}>分享图片</Button>
    </>
  );
}

export default SharePage;

这样就可以正常运行了。

const handleShare = async (text) => { const context = Taro.createCanvasContext('canvas'); const qrCodePath = text; const qrCodeInfo = await Taro.getImageInfo({ src: qrCodePath }); context.drawImage(qrCodeInfo.path, 0, 0, qrCodeInfo.width, qrCodeInfo.height, 0, 0, 400, 400); context.draw(false, async () => { await Taro.canvasToTempFilePath({ canvasId: 'canvas', fileType: 'jpg', quality: 1, success: (res) => { Taro.showShareImageMenu({ path: res.tempFilePath, success() { console.log('分享成功'); }, fail(err) { console.log('分享失败', err); }, }); }, fail(err) { console.log('canvasToTempFilePath 失败', err); }, }); }); }; 报错:getImageInfo:fail file not found"}

如果你的图片是 base64 编码的，那么你需要在调用 `Taro.getImageInfo` 方法时，使用 `src` 参数传入 `base64` 数据，而不是图片的路径。例如：

const qrCodePath = 'data:image/png;base64,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'
const qrCodeInfo = await Taro.getImageInfo({ src: qrCodePath });

另外需要注意的是，由于小程序的限制，`canvasToTempFilePath` 方法无法直接将 base64 图片转换成临时文件路径，因此你需要先将 base64 图片转换成 `wx.base64ToArrayBuffer` 类型的数据，再将它绘制到 canvas 上。你可以使用以下代码将 base64 图片转换成 `wx.base64ToArrayBuffer` 类型的数据：

const base64ToArrayBuffer = (base64) => {
  const binaryString = atob(base64.split(',')[1]);
  const len = binaryString.length;
  const bytes = new Uint8Array(len);
  for (let i = 0; i < len; i++) {
    bytes[i] = binaryString.charCodeAt(i);
  }
  return bytes.buffer;
};

const imageData = base64ToArrayBuffer(qrCodePath);

然后你可以将 `imageData` 传入 `Taro.canvasPutImageData` 方法，将它绘制到 canvas 上。最后再调用 `Taro.canvasToTempFilePath` 方法将 canvas 转换成临时文件路径即可。