android - getUidTxBytes(int uid) 在 android 6.0 中总是返回 0

Question

我正在尝试获取所有应用程序的网络流量统计信息。我只是打印设备中每个应用程序的总网络流量。该代码在 android 4.4 和 5.1 设备中运行良好，但在 android 6.0 设备中它始终为所有应用程序返回 0。任何人都可以告诉我为什么这发生在 android 6.0 设备上。

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    for(ApplicationInfo app : getPackageManager().getInstalledApplications(0)){
        long tx = TrafficStats.getUidTxBytes(app.uid);
        long rx = TrafficStats.getUidRxBytes(app.uid);
        long total = tx + rx;
        Log.e("total data of ", app.packageName + " = " + total);
    }
}

这是我的 AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mts.trafficstatsdemo">

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

Answer 1

根据 doc :

Starting in N this will only report traffic statistics for the calling UID. It will return UNSUPPORTED for all other UIDs for privacy reasons. To access historical network statistics belonging to other UIDs, use NetworkStatsManager.