ScanResults用两个字符串设置我的变量，但是返回值只有一个

Question

String essidPrefix = MainFragment.configuration.getEssidPrefix();
    wifiManager.startScan();
    results = wifiManager.getScanResults();
    for(ScanResult scanResult : results){
        String scanWifi = scanResult.SSID;
       if(scanWifi.startsWith(essidPrefix)){
           bssid = scanResult.BSSID;
           //bssid now has two strings, abc123 and abc1234 for example

       }
    }
   //bssid here only returns abc123
    return bssid;

如代码中所示，如何将abc123中的abc1234和scanResults.BSSID连接在一起，以便能够将其作为一个String返回？

Answer 1

如果我收到您的问题。

Java / Android 中的字符串concat。.

bssid = bssid+","+scanResult.BSSID; // comma separate

编辑

根据评论。您需要重置它。 bssid = ""; 因此您的代码将如下所示。

List<String> ids = new ArrayList<String>();
String essidPrefix = MainFragment.configuration.getEssidPrefix();
    wifiManager.startScan();
    results = wifiManager.getScanResults();
    bssid = ""; // this will reset it
    for(ScanResult scanResult : results){
        String scanWifi = scanResult.SSID;
       if(scanWifi.startsWith(essidPrefix)){
           // if you want to avoid null
           ids.add(scanResult.BSSID); // comma separate
       }
    }
   //bssid here only returns abc123
    return bssid = android.text.TextUtils.join(",", ids);

Answer 2

您应该使用StringBuilder（非线程安全）类进行串联，而不要使用'+'运算符（因为它会占用更多内存）。

String essidPrefix = MainFragment.configuration.getEssidPrefix();
wifiManager.startScan();
results = wifiManager.getScanResults();
StringBuilder sb = new StringBuilder();
for(ScanResult scanResult : results){
    String scanWifi = scanResult.SSID;
   if(scanWifi.startsWith(essidPrefix)){
       sb.append(scanResult.BSSID).append(",");
   }
}
sb.deleteCharAt((sb.length() - 1));
return sb.toString();