Show notification panel on downward swipe (#2099)

AndroidManifest-common.xml

@@ -45,6 +45,7 @@
     <uses-permission android:name="android.permission.REQUEST_DELETE_PACKAGES" />
     <uses-permission android:name="android.permission.READ_DEVICE_CONFIG" />
     <uses-permission android:name="android.permission.QUERY_ALL_PACKAGES" />
+    <uses-permission android:name="android.permission.EXPAND_STATUS_BAR" />
 
     <!-- TODO(b/150802536): Enabled only for ENABLE_FIXED_ROTATION_TRANSFORM feature flag -->
     <uses-permission android:name="android.permission.WRITE_SECURE_SETTINGS"/>

lawnchair/src/app/lawnchair/gestures/DirectionalGestureListener.kt

@@ -0,0 +1,63 @@
+package app.lawnchair.gestures
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.view.GestureDetector
+import android.view.GestureDetector.SimpleOnGestureListener
+import android.view.MotionEvent
+import android.view.View
+import android.view.View.OnTouchListener
+import kotlin.math.abs
+
+open class DirectionalGestureListener(ctx: Context?) : OnTouchListener {
+    private val mGestureDetector: GestureDetector
+
+    @SuppressLint("ClickableViewAccessibility")
+    override fun onTouch(v: View, event: MotionEvent): Boolean {
+        return mGestureDetector.onTouchEvent(event)
+    }
+
+    @Suppress("PrivatePropertyName")
+    private inner class GestureListener : SimpleOnGestureListener() {
+        private val SWIPE_THRESHOLD = 100
+        private val SWIPE_VELOCITY_THRESHOLD = 100
+
+        override fun onDown(e: MotionEvent): Boolean {
+            return true
+        }
+
+        private fun shouldReactToSwipe(diff: Float, velocity: Float): Boolean =
+            abs(diff) > SWIPE_THRESHOLD && abs(velocity) > SWIPE_VELOCITY_THRESHOLD
+
+        override fun onFling(e1: MotionEvent, e2: MotionEvent, velocityX: Float, velocityY: Float): Boolean {
+            return try {
+                val diffY = e2.y - e1.y
+                val diffX = e2.x - e1.x
+
+                when {
+                    abs(diffX) > abs(diffY) && shouldReactToSwipe(diffX, velocityX) -> {
+                        if (diffX > 0) onSwipeRight() else onSwipeLeft()
+                        true
+                    }
+                    shouldReactToSwipe(diffY, velocityY) -> {
+                        if (diffY > 0) onSwipeBottom() else onSwipeTop()
+                        true
+                    }
+                    else -> false
+                }
+            } catch (exception: Exception) {
+                exception.printStackTrace()
+                false
+            }
+        }
+    }
+
+    fun onSwipeRight() {}
+    fun onSwipeLeft() {}
+    fun onSwipeTop() {}
+    open fun onSwipeBottom() {}
+
+    init {
+        mGestureDetector = GestureDetector(ctx, GestureListener())
+    }
+}

lawnchair/src/app/lawnchair/gestures/SwipeDownGesture.java

@@ -0,0 +1,29 @@
+package app.lawnchair.gestures;
+
+import android.annotation.SuppressLint;
+import android.app.StatusBarManager;
+import android.content.Context;
+import android.os.Build;
+
+import androidx.annotation.RequiresApi;
+
+import com.android.quickstep.TouchInteractionService;
+
+public class SwipeDownGesture extends DirectionalGestureListener {
+
+    private final Context mContext;
+
+    public SwipeDownGesture(Context context) {
+        super(context);
+        mContext = context;
+    }
+
+    @SuppressLint("WrongConstant")
+    @RequiresApi(api = Build.VERSION_CODES.Q)
+    @Override
+    public void onSwipeBottom() {
+        if (!TouchInteractionService.isInitialized()) {
+            ((StatusBarManager) mContext.getSystemService("statusbar")).expandNotificationsPanel();
+        }
+    }
+}

src/com/android/launcher3/touch/WorkspaceTouchListener.java

@@ -43,6 +43,8 @@ import com.android.launcher3.testing.TestLogging;
 import com.android.launcher3.testing.TestProtocol;
 import com.android.launcher3.views.OptionsPopupView;
 
+import app.lawnchair.gestures.SwipeDownGesture;
+
 /**
  * Helper class to handle touch on empty space in workspace and show options popup on long press
  */
@@ -69,6 +71,7 @@ public class WorkspaceTouchListener extends GestureDetector.SimpleOnGestureListe
     private int mLongPressState = STATE_CANCELLED;
 
     private final GestureDetector mGestureDetector;
+    private final SwipeDownGesture mSwipeDown;
 
     public WorkspaceTouchListener(Launcher launcher, Workspace workspace) {
         mLauncher = launcher;
@@ -77,10 +80,12 @@ public class WorkspaceTouchListener extends GestureDetector.SimpleOnGestureListe
         // likely to cause movement.
         mTouchSlop = 2 * ViewConfiguration.get(launcher).getScaledTouchSlop();
         mGestureDetector = new GestureDetector(workspace.getContext(), this);
+        mSwipeDown = new SwipeDownGesture(workspace.getContext());
     }
 
     @Override
     public boolean onTouch(View view, MotionEvent ev) {
+        mSwipeDown.onTouch(view, ev);
         mGestureDetector.onTouchEvent(ev);
 
         int action = ev.getActionMasked();