Add option to clear key mappings

app/src/main/java/me/magnum/melonds/model/InputConfig.java

@@ -3,6 +3,8 @@ package me.magnum.melonds.model;
 import androidx.annotation.NonNull;
 
 public class InputConfig {
+    public static final int KEY_NOT_SET = -1;
+
     private Input input;
     private int key;
 
@@ -12,7 +14,7 @@ public class InputConfig {
     }
 
     public InputConfig(Input input) {
-        this(input, -1);
+        this(input, KEY_NOT_SET);
     }
 
     public Input getInput() {
@@ -28,7 +30,7 @@ public class InputConfig {
     }
 
     public boolean hasKeyAssigned() {
-        return key != -1;
+        return key != KEY_NOT_SET;
     }
 
     @NonNull

app/src/main/java/me/magnum/melonds/ui/inputsetup/InputSetupActivity.java

@@ -5,6 +5,7 @@ import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.ImageView;
 import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
@@ -45,6 +46,19 @@ public class InputSetupActivity extends AppCompatActivity {
                 waitingForInput = true;
                 inputUnderConfiguration = inputConfig;
             }
+
+            @Override
+            public void onInputConfigCleared(InputConfig inputConfig) {
+                if (inputUnderConfiguration != null) {
+                    if (inputConfig.getInput() == inputUnderConfiguration.getInput())
+                        viewModel.stopUpdatingInputConfig(inputConfig.getInput());
+
+                    inputUnderConfiguration = null;
+                    waitingForInput = false;
+                }
+
+                viewModel.clearInput(inputConfig.getInput());
+            }
         });
         this.inputListAdapter.setHasStableIds(true);
 
@@ -104,6 +118,7 @@ public class InputSetupActivity extends AppCompatActivity {
         public class InputViewHolder extends RecyclerView.ViewHolder {
             private TextView textInputName;
             private TextView textAssignedInputName;
+            private ImageView imageClearInput;
 
             private StatefulInputConfig inputConfig;
 
@@ -111,6 +126,7 @@ public class InputSetupActivity extends AppCompatActivity {
                 super(itemView);
                 this.textInputName = itemView.findViewById(R.id.text_input_name);
                 this.textAssignedInputName = itemView.findViewById(R.id.text_assigned_input_name);
+                this.imageClearInput = itemView.findViewById(R.id.image_input_clear);
             }
 
             public void setInputConfig(StatefulInputConfig config) {
@@ -166,6 +182,12 @@ public class InputSetupActivity extends AppCompatActivity {
                     inputConfigClickedListener.onInputConfigClicked(viewHolder.getInputConfig());
                 }
             });
+            viewHolder.imageClearInput.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    inputConfigClickedListener.onInputConfigCleared(viewHolder.getInputConfig());
+                }
+            });
 
             return viewHolder;
         }
@@ -188,5 +210,6 @@ public class InputSetupActivity extends AppCompatActivity {
 
     private interface OnInputConfigClickedListener {
         void onInputConfigClicked(InputConfig inputConfig);
+        void onInputConfigCleared(InputConfig inputConfig);
     }
 }

app/src/main/java/me/magnum/melonds/ui/inputsetup/InputSetupViewModel.java

@@ -82,6 +82,10 @@ public class InputSetupViewModel extends ViewModel {
         }
     }
 
+    public void clearInput(Input input) {
+        updateInputConfig(input, InputConfig.KEY_NOT_SET);
+    }
+
     private void onConfigsChanged() {
         inputConfigsBehaviour.onNext(this.inputConfigs);
 

app/src/main/res/drawable/ic_clear.xml

@@ -0,0 +1,5 @@
+<vector android:height="36dp" android:tint="#FFFFFF"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="36dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M19,6.41L17.59,5 12,10.59 6.41,5 5,6.41 10.59,12 5,17.59 6.41,19 12,13.41 17.59,19 19,17.59 13.41,12z"/>
+</vector>

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

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout 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="wrap_content"
@@ -32,10 +33,13 @@
     </LinearLayout>
 
     <ImageView
+            android:id="@+id/image_input_clear"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
             android:layout_alignParentRight="true"
             android:background="?attr/selectableItemBackground"
+            android:tint="@color/romConfigButtonDefault"
+            app:srcCompat="@drawable/ic_clear"
             android:layout_centerVertical="true" />
 </RelativeLayout>