1 files changed, 140 insertions, 0 deletions
diff --git a/src/android/app/src/main/java/org/citra/citra_emu/dialogs/MotionAlertDialog.java b/src/android/app/src/main/java/org/citra/citra_emu/dialogs/MotionAlertDialog.java
new file mode 100644
index 000000000..0f10f1858
--- /dev/null
+++ b/src/android/app/src/main/java/org/citra/citra_emu/dialogs/MotionAlertDialog.java
@@ -0,0 +1,140 @@
+package org.citra.citra_emu.dialogs;
+
+import android.content.Context;
+import android.view.InputDevice;
+import android.view.KeyEvent;
+import android.view.MotionEvent;
+
+import androidx.annotation.NonNull;
+import androidx.appcompat.app.AlertDialog;
+
+import org.citra.citra_emu.features.settings.model.view.InputBindingSetting;
+import org.citra.citra_emu.utils.Log;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * {@link AlertDialog} derivative that listens for
+ * motion events from controllers and joysticks.
+ */
+public final class MotionAlertDialog extends AlertDialog {
+    // The selected input preference
+    private final InputBindingSetting setting;
+    private final ArrayList<Float> mPreviousValues = new ArrayList<>();
+    private int mPrevDeviceId = 0;
+    private boolean mWaitingForEvent = true;
+
+    /**
+     * Constructor
+     *
+     * @param context The current {@link Context}.
+     * @param setting The Preference to show this dialog for.
+     */
+    public MotionAlertDialog(Context context, InputBindingSetting setting) {
+        super(context);
+
+        this.setting = setting;
+    }
+
+    public boolean onKeyEvent(int keyCode, KeyEvent event) {
+        Log.debug("[MotionAlertDialog] Received key event: " + event.getAction());
+        switch (event.getAction()) {
+            case KeyEvent.ACTION_UP:
+                setting.onKeyInput(event);
+                dismiss();
+                // Even if we ignore the key, we still consume it. Thus return true regardless.
+                return true;
+
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public boolean onKeyLongPress(int keyCode, @NonNull KeyEvent event) {
+        return super.onKeyLongPress(keyCode, event);
+    }
+
+    @Override
+    public boolean dispatchKeyEvent(KeyEvent event) {
+        // Handle this key if we care about it, otherwise pass it down the framework
+        return onKeyEvent(event.getKeyCode(), event) || super.dispatchKeyEvent(event);
+    }
+
+    @Override
+    public boolean dispatchGenericMotionEvent(@NonNull MotionEvent event) {
+        // Handle this event if we care about it, otherwise pass it down the framework
+        return onMotionEvent(event) || super.dispatchGenericMotionEvent(event);
+    }
+
+    private boolean onMotionEvent(MotionEvent event) {
+        if ((event.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) == 0)
+            return false;
+        if (event.getAction() != MotionEvent.ACTION_MOVE)
+            return false;
+
+        InputDevice input = event.getDevice();
+
+        List<InputDevice.MotionRange> motionRanges = input.getMotionRanges();
+
+        if (input.getId() != mPrevDeviceId) {
+            mPreviousValues.clear();
+        }
+        mPrevDeviceId = input.getId();
+        boolean firstEvent = mPreviousValues.isEmpty();
+
+        int numMovedAxis = 0;
+        float axisMoveValue = 0.0f;
+        InputDevice.MotionRange lastMovedRange = null;
+        char lastMovedDir = '?';
+        if (mWaitingForEvent) {
+            for (int i = 0; i < motionRanges.size(); i++) {
+                InputDevice.MotionRange range = motionRanges.get(i);
+                int axis = range.getAxis();
+                float origValue = event.getAxisValue(axis);
+                float value = origValue;//ControllerMappingHelper.scaleAxis(input, axis, origValue);
+                if (firstEvent) {
+                    mPreviousValues.add(value);
+                } else {
+                    float previousValue = mPreviousValues.get(i);
+
+                    // Only handle the axes that are not neutral (more than 0.5)
+                    // but ignore any axis that has a constant value (e.g. always 1)
+                    if (Math.abs(value) > 0.5f && value != previousValue) {
+                        // It is common to have multiple axes with the same physical input. For example,
+                        // shoulder butters are provided as both AXIS_LTRIGGER and AXIS_BRAKE.
+                        // To handle this, we ignore an axis motion that's the exact same as a motion
+                        // we already saw. This way, we ignore axes with two names, but catch the case
+                        // where a joystick is moved in two directions.
+                        // ref: bottom of https://developer.android.com/training/game-controllers/controller-input.html
+                        if (value != axisMoveValue) {
+                            axisMoveValue = value;
+                            numMovedAxis++;
+                            lastMovedRange = range;
+                            lastMovedDir = value < 0.0f ? '-' : '+';
+                        }
+                    }
+                    // Special case for d-pads (axis value jumps between 0 and 1 without any values
+                    // in between). Without this, the user would need to press the d-pad twice
+                    // due to the first press being caught by the "if (firstEvent)" case further up.
+                    else if (Math.abs(value) < 0.25f && Math.abs(previousValue) > 0.75f) {
+                        numMovedAxis++;
+                        lastMovedRange = range;
+                        lastMovedDir = previousValue < 0.0f ? '-' : '+';
+                    }
+                }
+
+                mPreviousValues.set(i, value);
+            }
+
+            // If only one axis moved, that's the winner.
+            if (numMovedAxis == 1) {
+                mWaitingForEvent = false;
+                setting.onMotionInput(input, lastMovedRange, lastMovedDir);
+                dismiss();
+            }
+        }
+        return true;
+    }
+}
+\ No newline at end of file