在Android WebView中，要实现从相机拍摄图片并上传，可以通过以下步骤实现：

1. 创建一个自定义的WebChromeClient类，重写其onShowFileChooser方法。该方法在用户选择上传文件时被调用。

public class MyWebChromeClient extends WebChromeClient {
    private ValueCallback mUploadCallback;
    private final static int FILE_CHOOSER_RESULT_CODE = 1;

    // For Android 5.0+
    public boolean onShowFileChooser(WebView webView, ValueCallback filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
        if (mUploadCallback != null) {
            mUploadCallback.onReceiveValue(null);
        }
        mUploadCallback = filePathCallback;

        Intent intent = fileChooserParams.createIntent();
        try {
            startActivityForResult(intent, FILE_CHOOSER_RESULT_CODE);
        } catch (ActivityNotFoundException e) {
            mUploadCallback = null;
            Toast.makeText(getContext(), "Cannot Open File Chooser", Toast.LENGTH_LONG).show();
            return false;
        }
        return true;
    }

    // For Android < 5.0
    public void openFileChooser(ValueCallback uploadMsg) {
        openFileChooser(uploadMsg, null);
    }

    // For Android 3.0+
    public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
        openFileChooser(uploadMsg, acceptType, null);
    }

    // For Android 4.1+
    public void openFileChooser(ValueCallback uploadMsg, String acceptType, String capture) {
        mUploadCallback = uploadMsg;

        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");

        startActivityForResult(Intent.createChooser(intent, "File Chooser"), FILE_CHOOSER_RESULT_CODE);
    }

    // Handle the file chooser result
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == FILE_CHOOSER_RESULT_CODE) {
            if (resultCode == Activity.RESULT_OK && mUploadCallback != null) {
                Uri[] result = null;
                if (data != null) {
                    String dataString = data.getDataString();
                    if (dataString != null) {
                        result = new Uri[]{Uri.parse(dataString)};
                    }
                }
                mUploadCallback.onReceiveValue(result);
            } else {
                mUploadCallback.onReceiveValue(null);
            }
            mUploadCallback = null;
        }
    }
}

2. 在你的WebView中设置自定义的WebChromeClient。

WebView webView = findViewById(R.id.webView);
webView.setWebChromeClient(new MyWebChromeClient());

现在，当用户点击上传按钮时，会弹出文件选择对话框，用户可以选择拍摄照片并上传。

注意：在AndroidManifest.xml文件中需要添加相机和存储权限。