1、加载网页后显示白板问题

//设置允许DOM存储
webSettings.setDomStorageEnabled(true);

2、选择文件无响应

2.1 重写WebChromeClient中openFileChooser和onShowFileChooser方法；

mWebView.setWebChromeClient(new WebChromeClient() {

            // 3.0 + 调用这个方法
            public void openFileChooser(ValueCallback filePathCallback, String acceptType) {
                getFile(filePathCallback);
            }

            // Android > 4.1.1 调用这个方法
            public void openFileChooser(ValueCallback<Uri> filePathCallback, String acceptType, String capture) {
                getFile(filePathCallback);

            }

            // Android > 5.0 调用这个方法
            @Override
            public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
                getFile(filePathCallback);
                return true;
            }
        });

2.2 跳转到选择文件的页面

//声明文件路径接收回调变量
private ValueCallback valueCallback;

//跳转到选择文件的页面
public void getFile(ValueCallback valueCallback) {
        //接收文件路径的回调
        this.valueCallback = valueCallback;
        Intent intent;
        //可以自己定义要跳转的文件系统页面
        if( Build.VERSION.SDK_INT >= 29 && this.getApplicationInfo().targetSdkVersion >= 29) {
            intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        }else {
            intent = new Intent(Intent.ACTION_GET_CONTENT);
        }
        intent.setType("image/*");
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        startActivityForResult(intent, REQUEST_CODE);
}

2.3 重写onActivityResult方法

 @Override
 protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE){
            if (resultCode == Activity.RESULT_OK) {
                selectH5File(data, valueCallback);
            }
        }
    }

2.4 接收选择的文件路径

public void selectH5File(Intent data, ValueCallback valueCallback){
        if (valueCallback == null){
            return;
        }
        try {
            Uri[] results = null;
            String dataString = data.getDataString();
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
                ClipData clipData = data.getClipData();
                if (clipData != null) {
                    results = new Uri[clipData.getItemCount()];
                    for (int i = 0; i < clipData.getItemCount(); i++) {
                        ClipData.Item item = clipData.getItemAt(i);
                        results[i] = item.getUri();
                    }
                }
            }
            if (dataString != null) {
                results = new Uri[]{Uri.parse(dataString)};
                valueCallback.onReceiveValue(results);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        valueCallback = null;
    }

3、文件取消选择后再次点击无响应

重写onActivityResult方法：

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE){
            if (resultCode == Activity.RESULT_OK) {
                selectH5File(data, valueCallback);
            } else {
                //取消选择
                if (valueCallback != null){
                    valueCallback.onReceiveValue(null);
                    valueCallback = null;
                }
            }
        }
    }