Question9：Android下如何獲取App的流量使用情況

在Android系統下有個文件夾專門記錄App的流量詳情。這個方法支持Android 2.2以上版本。

<Android>
package com.cx.cm.trafficbox.sys.u;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;

import com.cx.cm.trafficbox.sys.u.m.UidStat;

public final class TrafficStats {
	private static String UID_CONF = "/proc/uid_stat";
	private static String TCP_RCV = "tcp_rcv";
	private static String TCP_SND = "tcp_snd";

	public static List<UidStat> getStats(Context ctx) throws IOException {
		File temp = new File(UID_CONF);
		if (temp != null && temp.exists() && temp.isDirectory()) {
			// Mtk: high performance.
			return getUidStats();
		} else {
			// All of platform versions.
			return getUidStats(ctx);
		}
	}

	public static List<UidStat> getUidStats() throws IOException {
		List<UidStat> uidStats = new ArrayList<UidStat>();
		File temp = new File(UID_CONF);
		if (temp.exists() && temp.isDirectory()) {
			String[] a = temp.list();
			if (a != null && a.length > 0) {
				// LogUtils.df("getLoc", "<loc>", -1);

				for (int i = 0; i < a.length; i++) {
					File src = new File(UID_CONF + File.separator + a[i]);
					if (src.exists() && src.isDirectory()) {
						File tcpRcv = new File(src.getAbsolutePath()
								+ File.separator + TCP_RCV);
						File tcpSnd = new File(src.getAbsolutePath()
								+ File.separator + TCP_SND);
						int uid = Integer.parseInt(a[i]);
						UidStat uidStat = new UidStat();
						uidStat.uid = uid;
						long tcp_rcv = 0, tcp_snd = 0;
						if (tcpRcv.exists() && tcpRcv.isFile()) {
							FileReader in = new FileReader(tcpRcv);
							BufferedReader fr = new BufferedReader(in);
							tcp_rcv = Long.parseLong("" + fr.readLine());
							fr.close();
							in.close();
						}
						if (tcpSnd.exists() && tcpSnd.isFile()) {
							FileReader in = new FileReader(tcpSnd);
							BufferedReader fr = new BufferedReader(in);
							tcp_snd = Long.parseLong("" + fr.readLine());
							fr.close();
							in.close();
						}
						uidStat.tcp_rcv = tcp_rcv;
						uidStat.tcp_snd = tcp_snd;
						uidStats.add(uidStat);
						// LogUtils.df("uid:rcv:snd", uidStat.uid + ":"
						// + uidStat.tcp_rcv + ":" + uidStat.tcp_snd, 0);
					}
				} // for

				// LogUtils.df("getLoc", "</loc>", -1);
			}
		}
		// LogUtils.df("", "size:" + uidStats.size(), -1);
		return uidStats;
	}

	public static List<UidStat> getUidStats(Context ctx) {
		PackageManager pm = ctx.getPackageManager();
		List<PackageInfo> infos = pm
				.getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES
						| PackageManager.GET_PERMISSIONS);
		List<UidStat> uidStats = new ArrayList<UidStat>();
		int l = infos == null ? 0 : infos.size();
		for (int i = 0; i < l; i++) {
			PackageInfo info = infos.get(i);
			String[] premissions = info.requestedPermissions;
			if (premissions != null && premissions.length > 0) {
				for (String premission : premissions) {
					if ("android.permission.INTERNET".equals(premission)) {
						int uid = info.applicationInfo.uid;
						long rcv = android.net.TrafficStats.getUidRxBytes(uid);
						long snd = android.net.TrafficStats.getUidTxBytes(uid);
						// 如果返回-1，代表系統版本爲2.2以下，不支持使用該方法
						if (rcv < 0 || snd < 0) {
							continue;
						} else {
							if (rcv > 0 && snd > 0) {
								UidStat stat = new UidStat();
								stat.pkg = info.packageName;
								stat.uid = uid;
								stat.tcp_rcv = rcv;
								stat.tcp_snd = snd;
								uidStats.add(stat);
							}
						}
					}
				}
			}
		}
		return uidStats;
	}

}
</Android>

UidStat.java：

<Android>
package com.cx.cm.trafficbox.sys.u.m;

public final class UidStat {

	public int uid = -1;
	public String name = "";
	public String pkg = "";
	public long tcp_rcv = 0;
	public long tcp_snd = 0;
	public long stamp;
}
</Android>

在該文件夾下，按App（lication）的UID來分類保存其send和receive的所有TCP數據包的大小。每次開機後，該數據會重置爲0。