我试图以编程方式检测 Android 手机触发此“警告”时,已建立的互联网连接当前似乎无法访问(在此情况下:Edge/2G),如下所示:事实上,当出现此警告时,互联网无法访问,而没有警告时,可以正常访问。我目前正在做的是检测正确的网络。
public String getNetworkClass() {
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
return "Unknown";
} else {
int networkType = mTelephonyManager.getNetworkType();
Log.i("NETWORK", String.valueOf(networkType));
mobileNetworkType = networkType;
switch (networkType) {
case TelephonyManager.NETWORK_TYPE_GPRS:
case TelephonyManager.NETWORK_TYPE_EDGE:
case TelephonyManager.NETWORK_TYPE_CDMA:
case TelephonyManager.NETWORK_TYPE_1xRTT:
case TelephonyManager.NETWORK_TYPE_IDEN:
return "2G";
case TelephonyManager.NETWORK_TYPE_UMTS:
case TelephonyManager.NETWORK_TYPE_EVDO_0:
case TelephonyManager.NETWORK_TYPE_EVDO_A:
case TelephonyManager.NETWORK_TYPE_HSDPA:
case TelephonyManager.NETWORK_TYPE_HSUPA:
case TelephonyManager.NETWORK_TYPE_HSPA:
case TelephonyManager.NETWORK_TYPE_EVDO_B:
case TelephonyManager.NETWORK_TYPE_EHRPD:
case TelephonyManager.NETWORK_TYPE_HSPAP:
return "3G";
case TelephonyManager.NETWORK_TYPE_LTE:
return "4G";
case TelephonyManager.NETWORK_TYPE_NR:
return "5G";
default:
return "Unknown";
}
}
}
当网速为2G时,我正在测量下载/上传速率。我参考这里的建议,猜测下载速率低于150 kbps可能会导致该“警告”:
if(Arrays.asList(new String[]{"2G"}).contains(getNetworkClass())) {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkCapabilities nc = cm.getNetworkCapabilities(cm.getActiveNetwork());
int downSpeed = nc.getLinkDownstreamBandwidthKbps();
int upSpeed = nc.getLinkUpstreamBandwidthKbps();
if(downSpeed < 150) {
// I assume the connection is bad here
} else {
// All fine!
}
然而,我的测量值在每五秒钟之间在30到100 kbps之间波动,有时在这个范围内出现警告,有时则没有。
我该如何成功地捕获这个问题?是否有Android接口可以检查此问题?如果可能,我想要避免像ping检查这样的操作:
public boolean canAccessInternet() {
Runtime runtime = Runtime.getRuntime();
try {
Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
int exitValue = ipProcess.waitFor();
System.out.println("Network mExitValue " + exitValue);
return (exitValue == 0);
} catch (IOException e) {
System.out.println(" IO Error ");
e.printStackTrace();
} catch (InterruptedException e) {
System.out.println(" Interrupted Error ");
e.printStackTrace();
}
return false;
}