[Android Pro] Android7.0系統 關於Android獲取流量計數TrafficStats.getUidRxBytes(uid)和TrafficStats.getUidTxBytes(uid)返回-1解決方案

reference : http://blog.csdn.net/zhangyong7112/article/details/54574214

最近一個關於流量的項目在Android7.0系統的手機上運行，一直獲取不到流量的使用數據，查看源碼然后發現TrafficStats.getUidRxBytes(uid)和TrafficStats.getUidTxBytes(uid)一直都是返回的-1，

// 獲取某個網絡UID接收和發送字節的總和
long total = TrafficStats.getUidRxBytes(uid) + TrafficStats.getUidTxBytes(uid);

這就納悶了！！！然后多方查找資料，問了公司的大神，給我說可以在“/proc/uid_stat/"文件夾中讀取數據。后來總算是出來了。。。 不說了 貼代碼

if (total == 0 || (TrafficStats.getUidRxBytes(uid) == -1) && (TrafficStats.getUidTxBytes(uid) == -1)) {
    total = getTotalBytesManual(uid);
}

/**
     * 通過uid查詢文件夾中的數據
     * @param localUid
     * @return 
     */
    private Long getTotalBytesManual(int localUid) {
//        Log.e("BytesManual*****", "localUid:" + localUid);
        File dir = new File("/proc/uid_stat/");
        String[] children = dir.list();
        StringBuffer stringBuffer = new StringBuffer();
        for (int i = 0; i < children.length; i++) {
            stringBuffer.append(children[i]);
            stringBuffer.append("   ");
        }
//        Log.e("children*****", children.length + "");
//        Log.e("children22*****", stringBuffer.toString());
        if (!Arrays.asList(children).contains(String.valueOf(localUid))) {
            return 0L;
        }
        File uidFileDir = new File("/proc/uid_stat/" + String.valueOf(localUid));
        File uidActualFileReceived = new File(uidFileDir, "tcp_rcv");
        File uidActualFileSent = new File(uidFileDir, "tcp_snd");
        String textReceived = "0";
        String textSent = "0";
        try {
            BufferedReader brReceived = new BufferedReader(new FileReader(uidActualFileReceived));
            BufferedReader brSent = new BufferedReader(new FileReader(uidActualFileSent));
            String receivedLine;
            String sentLine;

            if ((receivedLine = brReceived.readLine()) != null) {
                textReceived = receivedLine;
//                Log.e("receivedLine*****", "receivedLine:" + receivedLine);
            }
            if ((sentLine = brSent.readLine()) != null) {
                textSent = sentLine;
//                Log.e("sentLine*****", "sentLine:" + sentLine);
            }
        } catch (IOException e) {
            e.printStackTrace();
//            Log.e("IOException*****", e.toString());
        }
//        Log.e("BytesManualEnd*****", "localUid:" + localUid);
        return Long.valueOf(textReceived).longValue() + Long.valueOf(textSent).longValue();
    }