Android full project with source how to react to WiFi state changes by registering a BroadcastReceiver with the WIFI_STATE_CHANGED_ACTION IntentFilter. The wifi state broadcast is a “sticky broadcast”, which means that it stays in the system and our BroadcastReceiver’s onReceive method will be triggered as soon as we call registerBroadcastReceiver and everytime we change the WiFi state. We register our receiver in onStart and unregister it in onStop. This way we can update our UI when the user for example enables/disables the WiFi in the quick settings dropdown menu. In this example we will react to WIFI_STATE_ENABLED and WIFI_STATE_DISABLED and update our user interface there. To access the WiFi state we have to set the ACCESS_WIFI_STATE and CHANGE_WIFI_STATE permissions in the AndroidManifest.xml file
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="tech.codingpoint.wifistateexample.MainActivity">
<Switch
android:id="@+id/wifi_switch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="WiFi is OFF "
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="tech.codingpoint.wifistateexample">
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
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>
</manifest>
MainActivity.java
package tech.codingpoint.wifistateexample;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.WifiManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.CompoundButton;
import android.widget.Switch;
public class MainActivity extends AppCompatActivity {
private Switch wifiSwitch;
private WifiManager wifiManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
wifiSwitch = findViewById(R.id.wifi_switch);
wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
wifiSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
wifiManager.setWifiEnabled(true);
wifiSwitch.setText("WiFi is ON");
} else {
wifiManager.setWifiEnabled(false);
wifiSwitch.setText("WiFi is OFF");
}
}
});
}
@Override
protected void onStart() {
super.onStart();
IntentFilter intentFilter = new IntentFilter(WifiManager.WIFI_STATE_CHANGED_ACTION);
registerReceiver(wifiStateReceiver, intentFilter);
}
@Override
protected void onStop() {
super.onStop();
unregisterReceiver(wifiStateReceiver);
}
private BroadcastReceiver wifiStateReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
int wifiStateExtra = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
WifiManager.WIFI_STATE_UNKNOWN);
switch (wifiStateExtra) {
case WifiManager.WIFI_STATE_ENABLED:
wifiSwitch.setChecked(true);
wifiSwitch.setText("WiFi is ON");
break;
case WifiManager.WIFI_STATE_DISABLED:
wifiSwitch.setChecked(false);
wifiSwitch.setText("WiFi is OFF");
break;
}
}
};
}