Add drawer with state information

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>
@@ skipping 28 matching lines @@
     {AMOTION_EVENT_ACTION_POINTER_UP, Window::kUp_InputState},
     {AMOTION_EVENT_ACTION_MOVE, Window::kMove_InputState},
     {AMOTION_EVENT_ACTION_CANCEL, Window::kUp_InputState},
 });
 
 SkiaAndroidApp::SkiaAndroidApp(JNIEnv* env, jobject androidApp) {
     env->GetJavaVM(&fJavaVM);
     fAndroidApp = env->NewGlobalRef(androidApp);
     jclass cls = env->GetObjectClass(fAndroidApp);
     fSetTitleMethodID = env->GetMethodID(cls, "setTitle", "(Ljava/lang/String;)V");
+    fSetStateMethodID = env->GetMethodID(cls, "setState", "(Ljava/lang/String;)V");
     fNativeWindow = nullptr;
     pthread_create(&fThread, nullptr, pthread_main, this);
 }
 
 SkiaAndroidApp::~SkiaAndroidApp() {
     fPThreadEnv->DeleteGlobalRef(fAndroidApp);
     if (fWindow) {
         fWindow->detach();
     }
     if (fNativeWindow) {
         ANativeWindow_release(fNativeWindow);
         fNativeWindow = nullptr;
     }
     if (fApp) {
         delete fApp;
     }
 }
 
 void SkiaAndroidApp::setTitle(const char* title) const {
     jstring titleString = fPThreadEnv->NewStringUTF(title);
     fPThreadEnv->CallVoidMethod(fAndroidApp, fSetTitleMethodID, titleString);
     fPThreadEnv->DeleteLocalRef(titleString);
 }
 
+void SkiaAndroidApp::setUIState(const Json::Value& state) const {
+    jstring jstr = fPThreadEnv->NewStringUTF(state.toStyledString().c_str());
+    fPThreadEnv->CallVoidMethod(fAndroidApp, fSetStateMethodID, jstr);
+    fPThreadEnv->DeleteLocalRef(jstr);
+}
+
 void SkiaAndroidApp::postMessage(const Message& message) const {
     SkDEBUGCODE(auto writeSize =) write(fPipes[1], &message, sizeof(message));
     SkASSERT(writeSize == sizeof(message));
 }
 
 void SkiaAndroidApp::readMessage(Message* message) const {
     SkDEBUGCODE(auto readSize =) read(fPipes[0], message, sizeof(Message));
     SkASSERT(readSize == sizeof(Message));
 }
 
@@ skipping 49 matching lines @@
             skiaAndroidApp->fWindow->onKey(it->second, Window::kUp_InputState, 0);
             break;
         }
         case kTouched: {
             auto it = ANDROID_TO_WINDOW_STATEMAP.find(message.fTouchState);
             SkASSERT(it != ANDROID_TO_WINDOW_STATEMAP.end());
             skiaAndroidApp->fWindow->onTouch(message.fTouchOwner, it->second, message.fTouchX,
                                              message.fTouchY);
             break;
         }
+        case kUIStateChanged: {
+            skiaAndroidApp->fWindow->onUIStateChanged(*message.stateName, *message.stateValue);
+            delete message.stateName;
+            delete message.stateValue;
+            break;
+        }
         default: {
             // do nothing
         }
     }
 
     return 1;  // continue receiving callbacks
 }
 
 void* SkiaAndroidApp::pthread_main(void* arg) {
     SkDebugf("pthread_main begins");
@@ skipping 70 matching lines @@
     JNIEnv* env, jobject activity, jlong handle, jint owner, jfloat x, jfloat y, jint state) {
     auto skiaAndroidApp = (SkiaAndroidApp*)handle;
     Message message(kTouched);
     message.fTouchOwner = owner;
     message.fTouchState = state;
     message.fTouchX = x;
     message.fTouchY = y;
     skiaAndroidApp->postMessage(message);
 }
 
+extern "C" JNIEXPORT void JNICALL Java_org_skia_viewer_ViewerActivity_onUIStateChanged(
+    JNIEnv* env, jobject activity, jlong handle, jstring stateName, jstring stateValue) {
+    auto skiaAndroidApp = (SkiaAndroidApp*)handle;
+    Message message(kUIStateChanged);
+    const char* nameChars = env->GetStringUTFChars(stateName, nullptr);
+    const char* valueChars = env->GetStringUTFChars(stateValue, nullptr);
+    message.stateName = new SkString(nameChars);
+    message.stateValue = new SkString(valueChars);
+    skiaAndroidApp->postMessage(message);
+    env->ReleaseStringUTFChars(stateName, nameChars);
+    env->ReleaseStringUTFChars(stateValue, valueChars);
+}
+
 }  // namespace sk_app