issue5542

Ensure DisplayListener.toString() returns a non-null value to prevent a
NullPointerException on certain devices.

Fixes #5537 <https://github.com/Genymobile/scrcpy/issues/5537>

doc/control.md

@@ -23,14 +23,20 @@ To control the device without mirroring:
 scrcpy --no-video --no-audio
 ```
 
-By default, mouse mode is switched to UHID if video mirroring is disabled (a
-relative mouse mode is required).
+By default, the mouse is disabled when video playback is turned off.
+
+To control the device using a relative mouse, enable UHID mouse mode:
+
+```bash
+scrcpy --no-video --no-audio --mouse=uhid
+scrcpy --no-video --no-audio -M  # short version
+```
 
 To also use a UHID keyboard, set it explicitly:
 
 ```bash
-scrcpy --no-video --no-audio --keyboard=uhid
-scrcpy --no-video --no-audio -K  # short version
+scrcpy --no-video --no-audio --mouse=uhid --keyboard=uhid
+scrcpy --no-video --no-audio -MK  # short version
 ```
 
 To use AOA instead (over USB only):

server/src/main/java/com/genymobile/scrcpy/CleanUp.java

@@ -207,13 +207,15 @@ public final class CleanUp {
             }
         }
 
-        if (displayId != Device.DISPLAY_ID_NONE && Device.isScreenOn(displayId)) {
+        // Change the power of the main display when mirroring a virtual display
+        int targetDisplayId = displayId != Device.DISPLAY_ID_NONE ? displayId : 0;
+        if (Device.isScreenOn(targetDisplayId)) {
             if (powerOffScreen) {
                 Ln.i("Power off screen");
-                Device.powerOffScreen(displayId);
+                Device.powerOffScreen(targetDisplayId);
             } else if (restoreDisplayPower) {
                 Ln.i("Restoring display power");
-                Device.setDisplayPower(displayId, true);
+                Device.setDisplayPower(targetDisplayId, true);
             }
         }
 

server/src/main/java/com/genymobile/scrcpy/control/Controller.java

@@ -281,7 +281,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                 setClipboard(msg.getText(), msg.getPaste(), msg.getSequence());
                 break;
             case ControlMessage.TYPE_SET_DISPLAY_POWER:
-                if (supportsInputEvents && displayId != Device.DISPLAY_ID_NONE) {
+                if (supportsInputEvents) {
                     setDisplayPower(msg.getOn());
                 }
                 break;
@@ -356,16 +356,27 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
         // it hides the field on purpose, to read it with atomic access
         @SuppressWarnings("checkstyle:HiddenField")
         DisplayData displayData = this.displayData.get();
-        assert displayData != null : "Cannot receive a touch event without a display";
+        // In scrcpy, displayData should never be null (a touch event can only be generated from the client on a video frame), but it is possible
+        // to send events without video playback using scrcpy-server alone (except for virtual displays).
+        assert displayData != null || displayId != Device.DISPLAY_ID_NONE : "Cannot receive a touch event without a display";
 
-        Point point = displayData.positionMapper.map(position);
-        if (point == null) {
-            if (Ln.isEnabled(Ln.Level.VERBOSE)) {
-                Size eventSize = position.getScreenSize();
-                Size currentSize = displayData.positionMapper.getVideoSize();
-                Ln.v("Ignore touch event generated for size " + eventSize + " (current size is " + currentSize + ")");
+        Point point;
+        int targetDisplayId;
+        if (displayData != null) {
+            point = displayData.positionMapper.map(position);
+            if (point == null) {
+                if (Ln.isEnabled(Ln.Level.VERBOSE)) {
+                    Size eventSize = position.getScreenSize();
+                    Size currentSize = displayData.positionMapper.getVideoSize();
+                    Ln.v("Ignore touch event generated for size " + eventSize + " (current size is " + currentSize + ")");
+                }
+                return false;
             }
-            return false;
+            targetDisplayId = displayData.virtualDisplayId;
+        } else {
+            // No display, use the raw coordinates
+            point = position.getPoint();
+            targetDisplayId = displayId;
         }
 
         int pointerIndex = pointersState.getPointerIndex(pointerId);
@@ -421,7 +432,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                     // First button pressed: ACTION_DOWN
                     MotionEvent downEvent = MotionEvent.obtain(lastTouchDown, now, MotionEvent.ACTION_DOWN, pointerCount, pointerProperties,
                             pointerCoords, 0, buttons, 1f, 1f, DEFAULT_DEVICE_ID, 0, source, 0);
-                    if (!Device.injectEvent(downEvent, displayData.virtualDisplayId, Device.INJECT_MODE_ASYNC)) {
+                    if (!Device.injectEvent(downEvent, targetDisplayId, Device.INJECT_MODE_ASYNC)) {
                         return false;
                     }
                 }
@@ -432,7 +443,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                 if (!InputManager.setActionButton(pressEvent, actionButton)) {
                     return false;
                 }
-                if (!Device.injectEvent(pressEvent, displayData.virtualDisplayId, Device.INJECT_MODE_ASYNC)) {
+                if (!Device.injectEvent(pressEvent, targetDisplayId, Device.INJECT_MODE_ASYNC)) {
                     return false;
                 }
 
@@ -446,7 +457,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                 if (!InputManager.setActionButton(releaseEvent, actionButton)) {
                     return false;
                 }
-                if (!Device.injectEvent(releaseEvent, displayData.virtualDisplayId, Device.INJECT_MODE_ASYNC)) {
+                if (!Device.injectEvent(releaseEvent, targetDisplayId, Device.INJECT_MODE_ASYNC)) {
                     return false;
                 }
 
@@ -454,7 +465,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
                     // Last button released: ACTION_UP
                     MotionEvent upEvent = MotionEvent.obtain(lastTouchDown, now, MotionEvent.ACTION_UP, pointerCount, pointerProperties,
                             pointerCoords, 0, buttons, 1f, 1f, DEFAULT_DEVICE_ID, 0, source, 0);
-                    if (!Device.injectEvent(upEvent, displayData.virtualDisplayId, Device.INJECT_MODE_ASYNC)) {
+                    if (!Device.injectEvent(upEvent, targetDisplayId, Device.INJECT_MODE_ASYNC)) {
                         return false;
                     }
                 }
@@ -465,7 +476,7 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
 
         MotionEvent event = MotionEvent.obtain(lastTouchDown, now, action, pointerCount, pointerProperties, pointerCoords, 0, buttons, 1f, 1f,
                 DEFAULT_DEVICE_ID, 0, source, 0);
-        return Device.injectEvent(event, displayData.virtualDisplayId, Device.INJECT_MODE_ASYNC);
+        return Device.injectEvent(event, targetDisplayId, Device.INJECT_MODE_ASYNC);
     }
 
     private boolean injectScroll(Position position, float hScroll, float vScroll, int buttons) {
@@ -691,9 +702,12 @@ public class Controller implements AsyncProcessor, VirtualDisplayListener {
     }
 
     private void setDisplayPower(boolean on) {
-        boolean setDisplayPowerOk = Device.setDisplayPower(displayId, on);
+        // Change the power of the main display when mirroring a virtual display
+        int targetDisplayId = displayId != Device.DISPLAY_ID_NONE ? displayId : 0;
+        boolean setDisplayPowerOk = Device.setDisplayPower(targetDisplayId, on);
         if (setDisplayPowerOk) {
-            keepDisplayPowerOff = !on;
+            // Do not keep display power off for virtual displays: MOD+p must wake up the physical device
+            keepDisplayPowerOff = displayId != Device.DISPLAY_ID_NONE && !on;
             Ln.i("Device display turned " + (on ? "on" : "off"));
             if (cleanUp != null) {
                 boolean mustRestoreOnExit = !on;

server/src/main/java/com/genymobile/scrcpy/device/Device.java

@@ -40,6 +40,10 @@ public final class Device {
     public static final int INJECT_MODE_WAIT_FOR_RESULT = InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT;
     public static final int INJECT_MODE_WAIT_FOR_FINISH = InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_FINISH;
 
+    // The new display power method introduced in Android 15 does not work as expected:
+    // <https://github.com/Genymobile/scrcpy/issues/5530>
+    private static final boolean USE_ANDROID_15_DISPLAY_POWER = false;
+
     private Device() {
         // not instantiable
     }
@@ -127,7 +131,7 @@ public final class Device {
     public static boolean setDisplayPower(int displayId, boolean on) {
         assert displayId != Device.DISPLAY_ID_NONE;
 
-        if (Build.VERSION.SDK_INT >= AndroidVersions.API_35_ANDROID_15) {
+        if (USE_ANDROID_15_DISPLAY_POWER && Build.VERSION.SDK_INT >= AndroidVersions.API_35_ANDROID_15) {
             return ServiceManager.getDisplayManager().requestDisplayPower(displayId, on);
         }
 

server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java

@@ -192,6 +192,9 @@ public final class DisplayManager {
                         if ("onDisplayChanged".equals(method.getName())) {
                             listener.onDisplayChanged((int) args[0]);
                         }
+                        if ("toString".equals(method.getName())) {
+                            return "DisplayListener";
+                        }
                         return null;
                     });
             try {