Warn users if Draw over other apps permission is missing

For android version >= 10(Q), a flash will be shown to users requesting them to grant the permission if they attempt to start a foreground terminal session command from background, like with the RUN_COMMAND intent. The flash will only be shown if "Plugin Error Notifications" toggle is enabled in settings.

app/src/main/java/com/termux/app/TermuxService.java

@@ -28,6 +28,7 @@ import com.termux.app.terminal.TermuxSessionClient;
 import com.termux.app.terminal.TermuxSessionClientBase;
 import com.termux.app.utils.Logger;
 import com.termux.app.utils.NotificationUtils;
+import com.termux.app.utils.PermissionUtils;
 import com.termux.app.utils.ShellUtils;
 import com.termux.app.utils.TextDataUtils;
 import com.termux.models.ExecutionCommand;
@@ -513,7 +514,12 @@ public final class TermuxService extends Service {
 
     /** Launch the {@link }TermuxActivity} to bring it to foreground. */
     private void startTermuxActivity() {
-        TermuxActivity.startTermuxActivity(this);
+        // For android >= 10, apps require Display over other apps permission to start foreground activities
+        // from background (services). If it is not granted, then termux sessions that are started will
+        // show in Termux notification but will not run until user manually clicks the notification.
+        if(PermissionUtils.validateDisplayOverOtherAppsPermissionForPostAndroid10(this)) {
+            TermuxActivity.startTermuxActivity(this);
+        }
     }
 
 

app/src/main/java/com/termux/app/utils/PermissionUtils.java

@@ -0,0 +1,86 @@
+package com.termux.app.utils;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.net.Uri;
+import android.os.Build;
+import android.provider.Settings;
+
+import androidx.core.content.ContextCompat;
+
+import com.termux.R;
+import com.termux.app.TermuxConstants;
+import com.termux.app.settings.preferences.TermuxAppSharedPreferences;
+
+import java.util.Arrays;
+
+public class PermissionUtils {
+
+    public static final int ACTION_MANAGE_OVERLAY_PERMISSION_REQUEST_CODE = 0;
+
+    private static final String LOG_TAG = "PluginUtils";
+
+    public static boolean checkPermissions(Context context, String[] permissions) {
+        int result;
+
+        for (String p:permissions) {
+            result = ContextCompat.checkSelfPermission(context,p);
+            if (result != PackageManager.PERMISSION_GRANTED) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static void askPermissions(Activity context, String[] permissions) {
+        if(context == null || permissions == null) return;
+
+        int result;
+        Logger.showToast(context, context.getString(R.string.message_sudo_please_grant_permissions), true);
+        try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}
+
+        for (String permission:permissions) {
+            result = ContextCompat.checkSelfPermission(context, permission);
+            if (result != PackageManager.PERMISSION_GRANTED) {
+                Logger.logDebug(LOG_TAG, "Requesting Permissions: " + Arrays.toString(permissions));
+                context.requestPermissions(new String[]{permission}, 0);
+            }
+        }
+    }
+
+
+
+    public static boolean checkDisplayOverOtherAppsPermission(Context context) {
+        boolean permissionGranted;
+
+        permissionGranted = Settings.canDrawOverlays(context);
+        if (!permissionGranted) {
+            Logger.logWarn(LOG_TAG, TermuxConstants.TERMUX_APP_NAME + " App does not have Display over other apps (SYSTEM_ALERT_WINDOW) permission");
+            return false;
+        } else {
+            Logger.logDebug(LOG_TAG, TermuxConstants.TERMUX_APP_NAME + " App already has Display over other apps (SYSTEM_ALERT_WINDOW) permission");
+            return true;
+        }
+    }
+
+    public static void askDisplayOverOtherAppsPermission(Activity context) {
+        Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION, Uri.parse("package:" + context.getPackageName()));
+        context.startActivityForResult(intent, ACTION_MANAGE_OVERLAY_PERMISSION_REQUEST_CODE);
+    }
+
+    public static boolean validateDisplayOverOtherAppsPermissionForPostAndroid10(Context context) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) return true;
+        
+        if(!PermissionUtils.checkDisplayOverOtherAppsPermission(context)) {
+            TermuxAppSharedPreferences preferences = new TermuxAppSharedPreferences(context);
+            if(preferences.getPluginErrorNotificationsEnabled())
+                Logger.showToast(context, context.getString(R.string.error_display_over_other_apps_permission_not_granted), true);
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+}

app/src/main/res/values/strings.xml

@@ -128,6 +128,12 @@
 
 
 
+    <!-- Termux PermissionUtils -->
+    <string name="message_sudo_please_grant_permissions">Please grant permissions on next screen</string>
+    <string name="error_display_over_other_apps_permission_not_granted">&TERMUX_APP_NAME; requires \"Display over other apps\" permission to start terminal sessions from background on Android >= 10. Grants it from Settings -> Apps -> &TERMUX_APP_NAME; -> Advanced</string>
+
+
+
     <!-- Termux File Receiver -->
     <string name="title_file_received">Save file in ~/downloads/</string>
     <string name="action_file_received_edit">Edit</string>