Android文件选择器未从Android Webview调用

这不是gradle文件错误。您只需要提供自定义的WebChromeClient，如下所示。

class MyWebChromeClient extends WebChromeClient {
    // For 3.0+ Devices (Start)
    // onActivityResult attached before constructor
    protected void openFileChooser(ValueCallback uploadMsg, String acceptType) {
        mUploadMessage = uploadMsg;
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("image/*");
        startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
    }


    // For Lollipop 5.0+ Devices
    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public boolean onShowFileChooser(WebView mWebView, ValueCallback filePathCallback, FileChooserParams fileChooserParams) {
        if (uploadMessage != null) {
            uploadMessage.onReceiveValue(null);
            uploadMessage = null;
        }

        uploadMessage = filePathCallback;

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

    //For Android 4.1 only
    protected void openFileChooser(ValueCallback uploadMsg, String acceptType, String capture) {
        mUploadMessage = uploadMsg;
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("image/*");
        startActivityForResult(Intent.createChooser(intent, "File Chooser"), FILECHOOSER_RESULTCODE);
    }

    protected void openFileChooser(ValueCallback uploadMsg) {
        mUploadMessage = uploadMsg;
        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType("image/*");
        startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
    }
}

并在您的网络视图中如下所示

webview.setWebChromeClient(new MyWebChromeClient());

其他一些有用的东西/变量将在全局中声明。

public ValueCallback uploadMessage;
private ValueCallback mUploadMessage;
public static final int REQUEST_SELECT_FILE = 100;
private final static int FILECHOOSER_RESULTCODE = 1;

确保您拥有所有读/写权限

更新

使用以下几行提供对存储中文件的访问。

webview.getSettings().setDomStorageEnabled(true);
webview.getSettings().setAllowContentAccess(true);
webview.getSettings().setAllowFileAccess(true);

更新2

在onActivityResult方法中获取结果。您可以使用如下所示的结果。

@Override
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        if (requestCode == REQUEST_SELECT_FILE) {
            if (uploadMessage == null)
                return;
            uploadMessage.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, intent));
            uploadMessage = null;
        }
    } else if (requestCode == FILECHOOSER_RESULTCODE) {
        if (null == mUploadMessage)
            return;
        // Use MainActivity.RESULT_OK if you're implementing WebView inside Fragment
        // Use RESULT_OK only if you're implementing WebView inside an Activity
        Uri result = intent == null || resultCode != WebLink.RESULT_OK ? null : intent.getData();
        mUploadMessage.onReceiveValue(result);
        mUploadMessage = null;
    } else
        Toast.makeText(WebLink.this, "Failed to Upload Image", Toast.LENGTH_LONG).show();
}