I want to implement things like the Android status bar and the filter list: the current Wi-Fi signal status icon is displayed after the link, and the signal strength of the surrounding links is displayed after the scan.

this question code mainly refers to this article:

 this.adapter = new SimpleAdapter( //
                MainActivity.this,  //
                arraylist, R.layout.wifi_scanresults_row, //
                new String[]{ITEM_KEY},
                new int[]{R.id.wifi_item}); //IDtextView
                /*new int[]{R.id.wifi_security};
                new int[]{R.id.wifi_StrongImage});*/

        listView.setAdapter(this.adapter); //
        
        ...
        
         @SuppressLint("StringFormatInvalid")
    @Override
    public void onClick(View v) {
        arraylist.clear(); //
        wifi.startScan(); //Wi-Fi

        try { //
            size = size - 1;
            while (size >= 0) { //size0
                HashMap<String, String> item = new HashMap<>();
                //wifiname.setText(getString(R.string.wifi_name, "" + results.get(size).SSID));
                //wifisec.setText(getString(R.string.wifi_security, "" + results.get(size).capabilities));
               // wifiImage.setImageLevel(getLayoutInflater(R.layout.wifi_sel, "" + listView.get()));

                item.put(ITEM_KEY, results.get(size).SSID + "\n" + results.get(size).capabilities); //Wi-Fi

                arraylist.add(item); //wifi
                size--; //size
                adapter.notifyDataSetChanged(); //
            }
        } catch (Exception e) //

        { }

my xml:
main.wifi_connect, main scan results, refer to the first link, and use the hashmap traversal method to get.

layout of scan_resuals_row: scan results, I try to make it similar to the system scan Wi-Fi list, but imageview can"t show it.

reference link: Android connection specifies Wifi
but he uses RecyclerView,. I use the ListView, switch in the first link. Is it expensive to switch?

Code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="...dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:gravity="center_vertical"
        android:paddingStart="10dp"
        android:paddingEnd="10dp"
        >
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:gravity="center_vertical"
        android:paddingStart="10dp"
        android:paddingEnd="10dp"
        >

        <TextView
            android:id="@+id/wifi_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:singleLine="true"
            android:text="@string/wifi_name"
            android:textSize="18sp" />

        <TextView
            android:id="@+id/wifi_security"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/wifi_security"
            android:textSize="14sp"/>

    </LinearLayout>

        <ImageView
            android:id="@+id/wifi_StrongImage"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            android:scaleType="fitXY"
            />

    </LinearLayout>

</RelativeLayout>

effect displayed:

figure shows the effect of selecting ImageView.

reference link to switch icons based on strength:
Android method to get the currently connected wifi signal strength

I created the xml:
selector.xml: switch signal strength icon selector, refer to the second link.

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">



    <item
        android:state_pressed="true"
        android:drawable="@drawable/ic_signal_wifi_4_bar_black_24dp">
    </item>

    <item
        android:state_pressed="false"
        android:drawable="@drawable/ic_perm_scan_wifi_black_24dp">

    </item>

    <item
        android:state_window_focused="false"
        android:drawable="@drawable/ic_signal_wifi_statusbar_null_black_26x24dp">
    </item>

</selector>

at present, my code just clicks on the button changed code, and does not get the surrounding Wi-Fi code, perhaps because it is annotated by itself in the code, or because you can only get the surrounding Wi-Fi, but the imageview with the same layout as the first question does not show up.

in the declaration of wifi message processing, whether the different state of Wi-Fi react or not, whether it is connected or not, what does this have to do with the value of Wi-Fi (that is, signal strength)?

// wifi
private BroadcastReceiver wifiIntentReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
    int wifi_state = intent.getIntExtra("wifi_state", 0);
    int level = Math.abs(((WifiManager)getSystemService(WIFI_SERVICE)).getConnectionInfo().getRssi());
    switch (wifi_state) {
    case WifiManager.WIFI_STATE_DISABLING:
    wifi_image.setImageResource(R.drawable.wifi_sel);
      wifi_image.setImageLevel(level);
      break;
    case WifiManager.WIFI_STATE_DISABLED:
      wifi_image.setImageResource(R.drawable.wifi_sel);
      wifi_image.setImageLevel(level);
      break;
    case WifiManager.WIFI_STATE_ENABLING:
      wifi_image.setImageResource(R.drawable.wifi_sel);
      wifi_image.setImageLevel(level);
      break;
    case WifiManager.WIFI_STATE_ENABLED:
      wifi_image.setImageResource(R.drawable.wifi_sel);
      wifi_image.setImageLevel(level);
      break;
    case WifiManager.WIFI_STATE_UNKNOWN:
      wifi_image.setImageResource(R.drawable.wifi_sel);
      wifi_image.setImageLevel(level);
      break;
    }
  }
};

Thank you.