Use swipe gesture to switch between slides on Android

tools/viewer/sk_app/android/surface_glue_android.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "surface_glue_android.h"
 
 #include <jni.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <unordered_map>
 
+#include <android/keycodes.h>
 #include <android/looper.h>
 #include <android/native_window_jni.h>
 
 #include "../Application.h"
 #include "SkTypes.h"
 #include "SkUtils.h"
 #include "Window_android.h"
 
 namespace sk_app {
 
 static const int LOOPER_ID_MESSAGEPIPE = 1;
 
+static const std::unordered_map<int, Window::Key> ANDROID_TO_WINDOW_KEYMAP({
+    {AKEYCODE_SOFT_LEFT, Window::Key::kLeft},
+    {AKEYCODE_SOFT_RIGHT, Window::Key::kRight}
+});
+
 void* pthread_main(void* arg);
 
 SkiaAndroidApp::SkiaAndroidApp() {
     fNativeWindow = nullptr;
     pthread_create(&fThread, nullptr, pthread_main, this);
 }
 
 SkiaAndroidApp::~SkiaAndroidApp() {
     if (fWindow) {
         fWindow->detach();
@@ skipping 46 matching lines @@
             auto window_android = (Window_android*)skiaAndroidApp->fWindow;
             window_android->initDisplay(skiaAndroidApp->fNativeWindow);
             skiaAndroidApp->paintIfNeeded();
             break;
         }
         case kSurfaceChanged: {
             SkASSERT(message.fNativeWindow == skiaAndroidApp->fNativeWindow &&
                      message.fNativeWindow);
             int width = ANativeWindow_getWidth(skiaAndroidApp->fNativeWindow);
             int height = ANativeWindow_getHeight(skiaAndroidApp->fNativeWindow);
-            skiaAndroidApp->fWindow->onResize(width, height);
             auto window_android = (Window_android*)skiaAndroidApp->fWindow;
             window_android->setContentRect(0, 0, width, height);
             skiaAndroidApp->paintIfNeeded();
             break;
         }
         case kSurfaceDestroyed: {
             if (skiaAndroidApp->fNativeWindow) {
                 auto window_android = (Window_android*)skiaAndroidApp->fWindow;
                 window_android->onDisplayDestroyed();
                 ANativeWindow_release(skiaAndroidApp->fNativeWindow);
                 skiaAndroidApp->fNativeWindow = nullptr;
             }
             break;
         }
+        case kKeyPressed: {
+            auto it = ANDROID_TO_WINDOW_KEYMAP.find(message.keycode);
+            SkASSERT(it != ANDROID_TO_WINDOW_KEYMAP.end());
+            // No modifier is supported so far
+            skiaAndroidApp->fWindow->onKey(it->second, Window::kDown_InputState, 0);
+            skiaAndroidApp->fWindow->onKey(it->second, Window::kUp_InputState, 0);
+            break;
+        }
         default: {
             // do nothing
         }
     }
 
     return 1;  // continue receiving callbacks
 }
 
 void* pthread_main(void* arg) {
     SkDebugf("pthread_main begins");
@@ skipping 46 matching lines @@
     message.fNativeWindow = ANativeWindow_fromSurface(env, surface);
     skiaAndroidApp->postMessage(message);
 }
 
 extern "C" JNIEXPORT void JNICALL Java_org_skia_viewer_ViewerActivity_onSurfaceDestroyed(
     JNIEnv* env, jobject activity, jlong handle) {
     auto skiaAndroidApp = (SkiaAndroidApp*)handle;
     skiaAndroidApp->postMessage(Message(kSurfaceDestroyed));
 }
 
+extern "C" JNIEXPORT void JNICALL Java_org_skia_viewer_ViewerActivity_onKeyPressed(JNIEnv* env,
+                                                                                   jobject activity,
+                                                                                   jlong handle,
+                                                                                   jint keycode) {
+    auto skiaAndroidApp = (SkiaAndroidApp*)handle;
+    Message message(kKeyPressed);
+    message.keycode = keycode;
+    skiaAndroidApp->postMessage(message);
+}
+
 }  // namespace sk_app