Flutter app - ability to turn off the screen - flutter

Question

Is there any way to lock the screen from Flutter app on Android?
I'm talking about the same action that happens when the user presses the phone's power button.

Answer 1

This is not available on flutter till now, for it we have to take the help of native implementation. Follow the below implementation.
Flutter Code:
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
static const platform = const MethodChannel('flutter.native/powerOff');
Future<void> responseFromNativeCode() async {
try {
await platform.invokeMethod('powerOff');
} on PlatformException catch (e) {
print("Failed to Invoke: '${e.message}'.");
}
}
#override
Widget build(BuildContext context) {
return Material(
child: Center(
child: RaisedButton(
child: Text('Turn Off'),
onPressed: responseFromNativeCode,
),
),
);
}
}
Java Code:
1. MainActivity
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import android.content.Context;
import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Intent;
import android.content.IntentFilter;
import android.widget.Toast;
public class MainActivity extends FlutterActivity {
private static final String CHANNEL = "flutter.native/powerOff";
static final int RESULT_ENABLE = 1;
DevicePolicyManager deviceManger;
ComponentName compName;
#Override
public void configureFlutterEngine(FlutterEngine flutterEngine) {
compName = new ComponentName(this, DeviceAdmin.class);
deviceManger = (DevicePolicyManager)
getSystemService(Context.DEVICE_POLICY_SERVICE);
super.configureFlutterEngine(flutterEngine);
new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL).setMethodCallHandler(
new MethodChannel.MethodCallHandler() {
#Override
public void onMethodCall(MethodCall call, MethodChannel.Result result) {
if (call.method.equals("powerOff")) {
Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, compName);
intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "You should enable the app!");
startActivityForResult(intent, RESULT_ENABLE);
}
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case RESULT_ENABLE:
if (resultCode == Activity.RESULT_OK) {
deviceManger.lockNow();
}
return;
}
}
}
2. Receiver Code
import android.app.admin.DeviceAdminReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class DeviceAdmin extends DeviceAdminReceiver {
#Override
public void onEnabled(Context context, Intent intent) {
super.onEnabled(context, intent);
Toast.makeText(context, "Enabled", Toast.LENGTH_SHORT).show();
}
#Override
public void onDisabled(Context context, Intent intent) {
super.onDisabled(context, intent);
Toast.makeText(context, "Disabled", Toast.LENGTH_SHORT).show();
}
}
3. AndroidMenifest.xml
<receiver
android:name=".DeviceAdmin"
android:description="#string/app_description"
android:label="#string/app_name"
android:permission="android.permission.BIND_DEVICE_ADMIN">
<meta-data
android:name="android.app.device_admin"
android:resource="#xml/policies" />
<intent-filter>
<action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
</intent-filter>
</receiver>
4.policies.xml - Add in res/xml folder
<?xml version="1.0" encoding="utf-8"?>
<device-admin>
<uses-policies>
<force-lock />
</uses-policies>
</device-admin>
and Finally, add String value in strings.xml file of the android project which required in the receiver

Answer 2

Hello maybe my answer is late but I made a plugin that performs exactly the implementation mentioned in the comment below with some other functions
device_policy_manager
and this how u can use it
/// Return `true` if the given administrator component is currently active (enabled) in the system.
final status = await DevicePolicyManager.isPermissionGranted();
/// request administrator permission
/// it will open the adminstartor permission page and return `true` once the permission granted.
/// An optional message providing additional explanation for why the admin is being added.
await DevicePolicyManager.requestPermession("Your app is requesting the Adminstration permission");
/// Remove administration permission from the current app.
await DevicePolicyManager.removeActiveAdmin();
/// Make the device lock immediately, as if the lock screen timeout has expired at the point of this call.
/// After this method is called, the device must be unlocked using strong authentication (PIN, pattern, or password).
await DevicePolicyManager.lockNow();
/// Determine whether or not the device's cameras have been disabled for this user.
final status = await DevicePolicyManager.isCameraDisabled();