Added option "show"

src/.idea/compiler.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="CompilerConfiguration">
-    <bytecodeTargetLevel target="1.8" />
+    <bytecodeTargetLevel target="11" />
   </component>
 </project>

src/app/build.gradle

@@ -10,7 +10,7 @@ android {
         minSdk 28
         targetSdk 32
         versionCode 1
-        versionName "0.1"
+        versionName "0.2"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
@@ -25,6 +25,9 @@ android {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
+    buildFeatures {
+        viewBinding true
+    }
 }
 
 dependencies {

src/app/release/output-metadata.json

@@ -12,7 +12,7 @@
       "filters": [],
       "attributes": [],
       "versionCode": 1,
-      "versionName": "1.0",
+      "versionName": "0.2",
       "outputFile": "app-release.apk"
     }
   ],

src/app/src/main/AndroidManifest.xml

@@ -24,22 +24,29 @@
         android:theme="@style/Theme.LocateMyDevice"
         tools:targetApi="30">
 
+        <activity
+            android:name=".ShowMessageActivity"
+            android:exported="false"
+            android:theme="@style/Theme.AppCompat.DayNight.NoActionBar">
+            <meta-data
+                android:name="android.app.lib_name"
+                android:value="" />
+        </activity>
         <!-- https://developer.android.com/guide/topics/manifest/receiver-element -->
         <receiver
             android:name=".SmsReceiver"
+            android:directBootAware="true"
             android:enabled="true"
             android:exported="true"
-            android:directBootAware="true"
             android:permission="android.permission.BROADCAST_SMS">
             <intent-filter>
                 <action android:name="android.provider.Telephony.SMS_RECEIVED" />
             </intent-filter>
         </receiver>
-
         <receiver
-            android:name="AdminReceiver"
-            android:permission="android.permission.BIND_DEVICE_ADMIN"
-            android:exported="true">
+            android:name=".AdminReceiver"
+            android:exported="true"
+            android:permission="android.permission.BIND_DEVICE_ADMIN">
             <meta-data
                 android:name="android.app.device_admin"
                 android:resource="@xml/device_admin" />
@@ -58,7 +65,9 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:label="Settings" android:name=".SettingsActivity"/>
+        <activity
+            android:name=".SettingsActivity"
+            android:label="Settings" />
     </application>
 
 </manifest>

src/app/src/main/java/com/xfarrow/locatemydevice/ShowMessageActivity.java

@@ -0,0 +1,51 @@
+package com.xfarrow.locatemydevice;
+
+import android.app.KeyguardManager;
+import android.content.Context;
+import android.os.Build;
+import android.os.Bundle;
+import androidx.appcompat.app.AppCompatActivity;
+import android.view.WindowManager;
+import android.widget.TextView;
+
+public class ShowMessageActivity extends AppCompatActivity {
+
+    private TextView textToDisplay;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_show_message);
+        showOnLockscreen();
+        setViews();
+        String messageToDisplay = getData();
+        textToDisplay.setText(messageToDisplay);
+    }
+
+    // https://stackoverflow.com/questions/35356848/android-how-to-launch-activity-over-lock-screen
+    private void showOnLockscreen(){
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1)
+        {
+            setShowWhenLocked(true);
+            setTurnScreenOn(true);
+        }
+        else
+        {
+            getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
+                    WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
+        }
+    }
+
+    private String getData(){
+        Bundle extras = getIntent().getExtras();
+        if (extras != null) {
+            return extras.getString(Utils.SHOW_MESSAGE_OPTION);
+        }
+        return null;
+    }
+
+    private void setViews(){
+        textToDisplay = findViewById(R.id.text_to_display);
+    }
+
+}

src/app/src/main/java/com/xfarrow/locatemydevice/SmsHandler.java

@@ -63,7 +63,9 @@ public class SmsHandler {
                 + "|"
                 + Utils.WIFI_OPTION + "((" + Utils.WIFI_ENABLE_SUBOPTION + ")|(" + Utils.WIFI_DISABLE_SUBOPTION + "))?"
                 + "|"
-                + Utils.LOCK_OPTION;
+                + Utils.LOCK_OPTION
+                + "|"
+                + Utils.SHOW_MESSAGE_OPTION + "\\s+\"[\\w\\W]*[\"]$";
 
         Pattern pattern = Pattern.compile(regexToMatch);
         Matcher matcher = pattern.matcher(message);
@@ -318,5 +320,16 @@ public class SmsHandler {
             Utils.sendSms(smsManager, responseSms.toString(), sender);
         }
 
+        //show
+        else if(providedOption.contains(Utils.SHOW_MESSAGE_OPTION)){
+            String messageToDisplay = message.substring(message.indexOf("\"") + 1,
+                    message.lastIndexOf("\""));
+
+            Intent lockScreenMessage = new Intent(context, ShowMessageActivity.class);
+            lockScreenMessage.putExtra(Utils.SHOW_MESSAGE_OPTION, messageToDisplay);
+            lockScreenMessage.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+            context.startActivity(lockScreenMessage);
+        }
+
     }
 }

src/app/src/main/java/com/xfarrow/locatemydevice/Utils.java

@@ -18,6 +18,7 @@ public class Utils {
     public static final String CALL_ME_OPTION = "callme";
     public static final String WIFI_OPTION = "wifi";
     public static final String LOCK_OPTION = "lock";
+    public static final String SHOW_MESSAGE_OPTION = "show";
     public static final String WIFI_ENABLE_SUBOPTION = "-enable";
     public static final String WIFI_DISABLE_SUBOPTION = "-disable";
 

src/app/src/main/res/layout/activity_show_message.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.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=".MainActivity">
+
+    <TextView
+        android:id="@+id/text_to_display"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="This device has been lost!"
+        android:textAppearance="@style/TextAppearance.AppCompat.Large"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        android:layout_marginStart="50dp"
+        android:layout_marginEnd="50dp"
+        android:maxWidth="350sp"/>
+</androidx.constraintlayout.widget.ConstraintLayout>