fix some lambda ref, use global android_app variable instead of passing as argument, fix clipboard utf issue by using byte array

src/app_events.cpp

@@ -2,8 +2,10 @@
 #include "app.h"
 
 #ifdef __ANDROID__
-void displayKeyboard(android_app* mApplication, bool pShow);
-void android_pick_file(android_app* mApplication, std::function<void(std::string)> callback);
+void displayKeyboard(bool pShow);
+void android_pick_file(std::function<void(std::string)> callback);
+std::string android_get_clipboard();
+bool android_set_clipboard(const std::string& s);
 #elif _WIN32
 std::string win32_open_file(const char* filter);
 std::string win32_open_dir();
@@ -21,6 +23,8 @@ std::string App::clipboard_get_text()
     return [ios_view clipboard_get_string];
 #elif __OSX__
     return [osx_view clipboard_get_string];
+#elif __ANDROID__
+    return android_get_clipboard();
 #endif
 }
 
@@ -32,6 +36,8 @@ bool App::clipboard_set_text(const std::string& s)
     return [ios_view clipboard_set_string:s];
 #elif __OSX__
     return [osx_view clipboard_set_string:s];
+#elif __ANDROID__
+    return android_set_clipboard(s);
 #endif
 }
 
@@ -93,7 +99,7 @@ void App::showKeyboard()
         [ios_view becomeFirstResponder];
     });
 #elif __ANDROID__
-    displayKeyboard(and_app, true);
+    displayKeyboard(true);
 #endif
 }
 
@@ -107,7 +113,7 @@ void App::hideKeyboard()
     //    [ios_view unregisterForKeyboardNotifications];
     });
 #elif __ANDROID__
-    displayKeyboard(and_app, false);
+    displayKeyboard(false);
 #endif
 }
 
@@ -126,7 +132,7 @@ void App::pick_image(std::function<void(std::string path)> callback)
             callback(path);
     });
 #elif __ANDROID__
-    android_pick_file(and_app, callback);
+    android_pick_file(callback);
 #elif _WIN32
     std::string path = win32_open_file("Image Files (*.jpg, *.png)\0*.jpg;*.png");
     if (!path.empty())
@@ -154,7 +160,7 @@ void App::pick_file(std::vector<std::string> types, std::function<void (std::str
             callback(path);
     });
 #elif __ANDROID__
-    android_pick_file(and_app, callback);
+    android_pick_file(callback);
 #elif _WIN32
     std::string filter = "Supported Files (";
     bool first_type = true;