Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference at libcore.net.UriCodec.encode(UriCodec.java:132) at java.net.URLEncoder.encode(URLEncoder.java:57) at com.baidu.ocr.sdk.utils.HttpsClient$RequestBody.setStrParams(HttpsClient.java:52) at com.baidu.ocr.sdk.utils.HttpUtil.post(HttpUtil.java:85) at com.baidu.ocr.sdk.OCR$3.onResult(OCR.java:377) at com.baidu.ocr.sdk.OCR.getToken(OCR.java:839) at com.baidu.ocr.sdk.OC...