Android 11 WebView打开文件选择按返回键后相机无法响应问题

根因分析 #

• Android 11及以上版本的onActivityResult逻辑中，用户点击返回键触发RESULT_CANCELED时，仅处理了file_req_code对应的file_data回调，未对图片选择常用的INPUT_FILE_REQUEST_CODE对应的mFilePathCallback进行回调通知和置空操作
• WebView的ValueCallback如果没有调用onReceiveValue方法，会一直处于等待状态，后续触发文件选择请求时不会再生成新的回调实例，导致点击无响应
• 低版本分支对取消场景做了明确的onReceiveValue(null)处理，所以不会出现该问题

修复步骤 #

1. 找到Android 11分支下的RESULT_CANCELED判断块，补全INPUT_FILE_REQUEST_CODE的处理逻辑
2. 补充results变量的非空判断，避免取消场景下空指针崩溃

修复后完整代码片段 #

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                getLineNumber() + " --> Camera onActivityResult Version R and Greater -->  requestCode -->  " + requestCode);
        if (requestCode != INPUT_FILE_REQUEST_CODE || mFilePathCallback == null)
        {

            writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                    getLineNumber() + " --> Camera onActivityResult   requestCode --> NULL ");
            super.onActivityResult(requestCode, resultCode, intent);
            return;
        }

        Uri[] results = null;

        // Check that the response is a good one
        if (resultCode == Activity.RESULT_OK) {
            writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                    getLineNumber() + " --> Camera onActivityResult  -->  RESULT_OK  ");


            if (intent == null) {
                writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                        getLineNumber() + " --> Camera onActivityResult   data   -->  null  ");

                // If there is not data, then we may have taken a photo
                if (mCameraPhotoPath != null) {

                    writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                            getLineNumber() + " --> Camera onActivityResult   mCameraPhotoPath   --> not  null  ");

                    results = new Uri[]{Uri.parse(mCameraPhotoPath)};
                }
            } else {
                writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                        getLineNumber() + " --> Camera onActivityResult   DATA   --> NOT  null  ");

                String dataString = intent.getDataString();
                writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                        getLineNumber() + " --> Camera onActivityResult   DATA   --> NOT  null dataString "+dataString);


                if (dataString != null)
                {
                    results = new Uri[]{Uri.parse(dataString)};
                    writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                            getLineNumber() + " --> Camera onActivityResult   dataString   --> NOT  null  ");


                }
                else
                {
                    writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                            getLineNumber() + " --> Camera onActivityResult   dataString   --> NULL  ");

                    results = new Uri[]{pictureUri};
                }

            }

            mFilePathCallback.onReceiveValue(results);
            mFilePathCallback = null;

        }
        else if (resultCode == Activity.RESULT_CANCELED) {
            Log.e(TAG, "Image file selection canceled");
            // 补全INPUT_FILE_REQUEST_CODE的取消处理，解决后续无法触发的问题
            if (requestCode == INPUT_FILE_REQUEST_CODE && mFilePathCallback != null) {
                mFilePathCallback.onReceiveValue(null);
                mFilePathCallback = null;
            }
            if (requestCode == file_req_code) {
                if (null == file_data)
                    return;
                Uri result = intent == null || resultCode != Activity.RESULT_OK ? null : intent.getData();
                file_data.onReceiveValue(result);
                file_data = null;
            }
        }
        // 补全非空判断，避免空指针崩溃
        if(results != null && results.length > 0) {
            writeLog("Web Frame -->" + Thread.currentThread().getStackTrace()[1].
                    getLineNumber() + " --> Camera onActivityResult   Length   -->   "+results.length+" result "+results[0].toString());
        }
    } else if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.Q) {

        writeLog("Web Screen -->"+ Thread.currentThread().getStackTrace()[1].
                getLineNumber()+" Camera onActivityResult--> Inside Version Q or Less");
        Uri[] results = null;
        /*-- if file request cancelled; exited camera. we need to send null value to make future attempts workable --*/
        if (resultCode == Activity.RESULT_CANCELED) {
            if (requestCode == file_req_code) {
                file_path.onReceiveValue(null);
                return;
            }
        }


        /*-- continue if response is positive --*/
        if (resultCode == Activity.RESULT_OK) {
            if (requestCode == file_req_code) {
                if (null == file_path) {
                    return;
                }

                ClipData clipData;
                String stringData;
                try {
                    clipData = intent.getClipData();
                    stringData = intent.getDataString();
                } catch (Exception e) {
                    clipData = null;
                    stringData = null;
                }

                if (clipData == null && stringData == null && cam_file_data != null) {
                    results = new Uri[]{
                            Uri.parse(cam_file_data)
                    };
                } else {
                    if (clipData != null) { // checking if multiple files selected or not
                        final int numSelectedFiles = clipData.getItemCount();
                        results = new Uri[numSelectedFiles];
                        for (int i = 0; i < clipData.getItemCount(); i++) {
                            results[i] = clipData.getItemAt(i).getUri();
                        }
                    } else {
                        results = new Uri[]{
                                Uri.parse(stringData)
                        };
                    }
                }
            }
        }
        file_path.onReceiveValue(results);
        file_path = null;
    } else {
        if (requestCode == file_req_code) {
            if (null == file_data)
                return;
            Uri result = intent == null || resultCode != Activity.RESULT_OK ? null : intent.getData();
            file_data.onReceiveValue(result);
            file_data = null;
        }
    }
}

内容的提问来源于stack exchange，提问作者Malhotra