new sample app

KBMouse/Context/app/build.gradle

@@ -0,0 +1,17 @@
+apply plugin: 'com.android.application'
+
+dependencies {
+    compile 'com.android.support:recyclerview-v7:23.4.0'
+    compile 'com.squareup.picasso:picasso:2.5.2'
+}
+
+android {
+    compileSdkVersion 23
+    buildToolsVersion "23.0.2"
+
+    defaultConfig {
+        minSdkVersion 16
+        targetSdkVersion 23
+        applicationId "com.commonsware.android.kbmouse.context"
+    }
+}

KBMouse/Context/app/src/main/AndroidManifest.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<manifest package="com.commonsware.android.kbmouse.hotkeys"
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:versionCode="1"
+  android:versionName="1.0">
+
+  <supports-screens
+    android:anyDensity="true"
+    android:largeScreens="true"
+    android:normalScreens="true"
+    android:smallScreens="true" />
+
+  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+
+  <application
+    android:icon="@drawable/ic_launcher"
+    android:label="@string/app_name"
+    android:theme="@style/Theme.Apptheme">
+    <activity android:name=".MainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN" />
+
+        <category android:name="android.intent.category.LAUNCHER" />
+      </intent-filter>
+    </activity>
+  </application>
+
+</manifest>

KBMouse/Context/app/src/main/java/com/commonsware/android/kbmouse/hotkeys/ChoiceCapableAdapter.java

@@ -0,0 +1,163 @@
+/***
+ Copyright (c) 2015 CommonsWare, LLC
+ Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ use this file except in compliance with the License. You may obtain	a copy
+ of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
+ by applicable law or agreed to in writing, software distributed under the
+ License is distributed on an "AS IS" BASIS,	WITHOUT	WARRANTIES OR CONDITIONS
+ OF ANY KIND, either express or implied. See the License for the specific
+ language governing permissions and limitations under the License.
+
+ From _The Busy Coder's Guide to Android Development_
+ https://commonsware.com/Android
+ */
+
+package com.commonsware.android.kbmouse.hotkeys;
+
+import android.os.Bundle;
+import android.support.v7.widget.RecyclerView;
+import android.view.KeyEvent;
+import android.view.View;
+
+abstract public class
+    ChoiceCapableAdapter<T extends RecyclerView.ViewHolder>
+    extends RecyclerView.Adapter<T> {
+  private static final long KEY_TIME_DELTA=250;
+  private final ChoiceMode choiceMode;
+  private final RecyclerView rv;
+  private long lastDownKeyTime=-1L;
+  private long lastUpKeyTime=-1L;
+
+  public ChoiceCapableAdapter(RecyclerView rv,
+                              ChoiceMode choiceMode) {
+    super();
+    this.rv=rv;
+    this.choiceMode=choiceMode;
+  }
+
+  void onChecked(int position, boolean isChecked) {
+    onChecked(position, isChecked, false);
+  }
+
+  void onChecked(int position, boolean isChecked, boolean updateUI) {
+    if (choiceMode.isSingleChoice()) {
+      int checked=choiceMode.getCheckedPosition();
+
+      if (checked>=0) {
+        RowController row=
+            (RowController)rv.findViewHolderForAdapterPosition(checked);
+
+        if (row!=null) {
+          row.setChecked(false);
+        }
+      }
+    }
+
+    choiceMode.setChecked(position, isChecked);
+
+    if (updateUI) {
+      notifyItemChanged(position);
+      rv.scrollToPosition(position);
+    }
+  }
+
+  boolean isChecked(int position) {
+    return(choiceMode.isChecked(position));
+  }
+
+  int getCheckedPosition() {
+    if (choiceMode.isSingleChoice()) {
+      return(choiceMode.getCheckedPosition());
+    }
+
+    throw new IllegalStateException("Can only get checked position for single-choice");
+  }
+
+  void onSaveInstanceState(Bundle state) {
+    choiceMode.onSaveInstanceState(state);
+  }
+
+  void onRestoreInstanceState(Bundle state) {
+    choiceMode.onRestoreInstanceState(state);
+  }
+
+  @Override
+  public void onViewAttachedToWindow(T holder) {
+    super.onViewAttachedToWindow(holder);
+
+    if (holder.getAdapterPosition()!=choiceMode.getCheckedPosition()) {
+      ((RowController)holder).setChecked(false);
+    }
+  }
+
+  // inspired by http://stackoverflow.com/a/28838834/115145
+
+  @Override
+  public void onAttachedToRecyclerView(RecyclerView rv) {
+    super.onAttachedToRecyclerView(rv);
+
+    if (choiceMode.isSingleChoice()) {
+      rv.setOnKeyListener(new View.OnKeyListener() {
+        @Override
+        public boolean onKey(View v, int keyCode, KeyEvent event) {
+          if (event.getAction()==KeyEvent.ACTION_DOWN) {
+            switch (keyCode) {
+              case KeyEvent.KEYCODE_DPAD_DOWN:
+                return(chooseNext());
+              case KeyEvent.KEYCODE_DPAD_UP:
+                return(choosePrevious());
+            }
+          }
+
+          return(false);
+        }
+      });
+    }
+  }
+
+  private boolean chooseNext() {
+    long now=System.currentTimeMillis();
+    boolean result=false;
+
+    if (lastDownKeyTime==-1 || now-lastDownKeyTime>KEY_TIME_DELTA) {
+      lastDownKeyTime=now;
+      lastUpKeyTime=-1L;
+
+      int checked=choiceMode.getCheckedPosition();
+
+      if (checked<0) {
+        onChecked(0, true, true);
+        result=true;
+      }
+      else if (checked<getItemCount()-1) {
+        onChecked(checked+1, true, true);
+        result=true;
+      }
+    }
+
+    return(result);
+  }
+
+  private boolean choosePrevious() {
+    long now=System.currentTimeMillis();
+    boolean result=false;
+
+    if (lastUpKeyTime==-1 || now-lastUpKeyTime>KEY_TIME_DELTA) {
+      lastUpKeyTime=now;
+      lastDownKeyTime=-1L;
+
+      int checked=choiceMode.getCheckedPosition();
+
+      if (checked>0) {
+        onChecked(checked-1, true, true);
+        result=true;
+      }
+      else if (checked<0) {
+        onChecked(0, true, true);
+        result=true;
+      }
+    }
+
+    return(result);
+  }
+}

KBMouse/Context/app/src/main/java/com/commonsware/android/kbmouse/hotkeys/ChoiceMode.java

@@ -0,0 +1,26 @@
+/***
+ Copyright (c) 2015 CommonsWare, LLC
+ Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ use this file except in compliance with the License. You may obtain	a copy
+ of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
+ by applicable law or agreed to in writing, software distributed under the
+ License is distributed on an "AS IS" BASIS,	WITHOUT	WARRANTIES OR CONDITIONS
+ OF ANY KIND, either express or implied. See the License for the specific
+ language governing permissions and limitations under the License.
+
+ From _The Busy Coder's Guide to Android Development_
+ https://commonsware.com/Android
+ */
+
+package com.commonsware.android.kbmouse.hotkeys;
+
+import android.os.Bundle;
+
+public interface ChoiceMode {
+  boolean isSingleChoice();
+  int getCheckedPosition();
+  void setChecked(int position, boolean isChecked);
+  boolean isChecked(int position);
+  void onSaveInstanceState(Bundle state);
+  void onRestoreInstanceState(Bundle state);
+}