Use LauncherCallbacks model instead of method overrides

-> When extending the Launcher Activity, instead of overriding
   public and protected methods, create a proper interface
-> This helps define the interface when extending Launcher
   more formally and more clearly

Change-Id: Ib38e8a376b2242d4078bf6856bb145f5b5f0da80

src/com/android/launcher3/LauncherCallbacks.java

@@ -0,0 +1,89 @@
+package com.android.launcher3;
+
+import android.content.ComponentName;
+import android.content.Intent;
+import android.graphics.Rect;
+import android.os.Bundle;
+import android.view.Menu;
+import android.view.View;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+
+/**
+ * LauncherCallbacks is an interface used to extend the Launcher activity. It includes many hooks
+ * in order to add additional functionality. Some of these are very general, and give extending
+ * classes the ability to react to Activity life-cycle or specific user interactions. Others
+ * are more specific and relate to replacing parts of the application, for example, the search
+ * interface or the wallpaper picker.
+ */
+public interface LauncherCallbacks {
+
+    /*
+     * Activity life-cycle methods. These methods are triggered after
+     * the code in the corresponding Launcher method is executed.
+     */
+    public void preOnCreate();
+    public void onCreate(Bundle savedInstanceState);
+    public void preOnResume();
+    public void onResume();
+    public void onStart();
+    public void onStop();
+    public void onPause();
+    public void onDestroy();
+    public void onSaveInstanceState(Bundle outState);
+    public void onPostCreate(Bundle savedInstanceState);
+    public void onNewIntent(Intent intent);
+    public void onActivityResult(int requestCode, int resultCode, Intent data);
+    public void onWindowFocusChanged(boolean hasFocus);
+    public boolean onPrepareOptionsMenu(Menu menu);
+    public void dump(String prefix, FileDescriptor fd, PrintWriter w, String[] args);
+    public void onHomeIntent();
+    public boolean handleBackPressed();
+
+    /*
+     * Extension points for providing custom behavior on certain user interactions.
+     */
+    public void onLauncherProviderChange();
+    public void finishBindingItems(final boolean upgradePath);
+    public void onClickAllAppsButton(View v);
+    public void bindAllApplications(ArrayList<AppInfo> apps);
+    public void onClickFolderIcon(View v);
+    public void onClickAppShortcut(View v);
+    public void onClickPagedViewIcon(View v);
+    public void onClickWallpaperPicker(View v);
+    public void onClickSettingsButton(View v);
+    public void onClickAddWidgetButton(View v);
+    public void onPageSwitch(View newPage, int newPageIndex);
+    public void onWorkspaceLockedChanged();
+    public void onDragStarted(View view);
+    public void onInteractionBegin();
+    public void onInteractionEnd();
+
+    /*
+     * Extension points for replacing the search experience
+     */
+    public boolean forceDisableVoiceButtonProxy();
+    public boolean providesSearch();
+    public boolean startSearch(String initialQuery, boolean selectInitialQuery,
+            Bundle appSearchData, Rect sourceBounds);
+    public void startVoice();
+    public boolean hasCustomContentToLeft();
+    public void populateCustomContentContainer();
+    public View getQsbBar();
+
+    /*
+     * Extensions points for adding / replacing some other aspects of the Launcher experience.
+     */
+    public Intent getFirstRunActivity();
+    public boolean hasFirstRunActivity();
+    public boolean hasDismissableIntroScreen();
+    public View getIntroScreen();
+    public boolean shouldMoveToDefaultScreenOnHomeIntent();
+    public boolean hasSettings();
+    public ComponentName getWallpaperPickerComponent();
+    public boolean overrideWallpaperDimensions();
+    public boolean isLauncherPreinstalled();
+
+}