UPDATE: Migrate to LiveData based ViewModel, with Activity reference …

…removed from AppListViewModel.

app/build.gradle

@@ -37,9 +37,10 @@ dependencies {
 
     // Any dependency with classes involved in data-binding in feature module must be declared with "api",
     // since these classes are used in data-binding task of dependent module ("assembly").
-    api 'com.android.support:design:27.0.2'
-    api 'com.android.support:appcompat-v7:27.0.2'
-    api 'com.android.support:cardview-v7:27.0.2'
+    api 'android.arch.lifecycle:extensions:1.1.1'
+    api 'com.android.support:appcompat-v7:27.1.1'
+    api 'com.android.support:design:27.1.1'
+    api 'com.android.support:cardview-v7:27.1.1'
     api 'eu.chainfire:libsuperuser:1.0.0.201510071325'
     api 'uk.co.samuelwall:material-tap-target-prompt:2.0.1'
     api(name: 'setup-wizard-lib-platform-release', ext: 'aar')

app/src/main/java/com/oasisfeng/common/app/BaseAppListViewModel.java

@@ -1,13 +1,11 @@
 package com.oasisfeng.common.app;
 
-import android.databinding.BaseObservable;
-import android.databinding.Bindable;
+import android.arch.lifecycle.MutableLiveData;
+import android.arch.lifecycle.ViewModel;
 import android.databinding.ObservableList;
-import android.support.annotation.Nullable;
 import android.util.Log;
 
 import com.oasisfeng.android.databinding.ObservableSortedList;
-import com.oasisfeng.island.mobile.BR;
 import com.oasisfeng.island.model.AppViewModel;
 
 import java.util.HashMap;
@@ -19,7 +17,7 @@
  *
  * Created by Oasis on 2016/6/24.
  */
-public class BaseAppListViewModel<T extends AppViewModel> extends BaseObservable {
+public class BaseAppListViewModel<T extends AppViewModel> extends ViewModel {
 
 	// TODO: Rebuild the whole AbstractAppListViewModel to keep immutability?
 	protected void replaceApps(final List<T> apps) {
@@ -36,7 +34,7 @@ protected T putApp(final String pkg, final T app) {
 			Log.d(TAG, "Update in place: " + pkg);
 			final int index = mApps.indexOf(old_app_vm);
 			mApps.updateItemAt(index, app);
-			if (mSelection == old_app_vm) setSelection(app);	// Keep the selection unchanged
+			if (mSelection.getValue() == old_app_vm) setSelection(app);	// Keep the selection unchanged
 		} else {
 			Log.d(TAG, "Put: " + pkg);
 			mApps.add(app);
@@ -67,26 +65,23 @@ protected void removeApp(final String pkg) {
 		if (app == null) return;
 		Log.d(TAG, "Remove: " + pkg);
 		mApps.remove(app);
-		if (mSelection == app) setSelection(null);
+		if (mSelection.getValue() == app) setSelection(null);
 	}
 
 	protected boolean contains(final String pkg) { return mAppsByPackage.containsKey(pkg); }
 	protected int size() { return mApps.size(); }
 
 	/* Selection related */
 
-	@SuppressWarnings("WeakerAccess"/* Publicly accessed in app_detail.xml */) @Bindable public @Nullable T getSelection() { return mSelection; }
-
 	public void clearSelection() {
 		setSelection(null);
 	}
 
 	protected void setSelection(final T selection) {
-		if (mSelection == selection) return;
-		if (mSelection != null) mSelection.selected.set(false);
-		mSelection = selection;
-		if (selection != null) selection.selected.set(true);
-		notifyPropertyChanged(BR.selection);
+		if (mSelection.getValue() == selection) return;
+		if (mSelection.getValue() != null) mSelection.getValue().selected.setValue(false);
+		mSelection.setValue(selection);
+		if (selection != null) selection.selected.setValue(true);
 	}
 
 	protected BaseAppListViewModel(final Class<T> clazz) {
@@ -97,5 +92,5 @@ protected BaseAppListViewModel(final Class<T> clazz) {
 
 	private final ObservableSortedList<T> mApps;
 	private final Map<String, T> mAppsByPackage = new HashMap<>();	// Enforced constraint: apps from different users must not be shown at the same time.
-	private transient T mSelection;
+	public final MutableLiveData<T> mSelection = new MutableLiveData<>();
 }

app/src/main/java/com/oasisfeng/common/app/BaseAppViewModel.java

@@ -1,13 +1,15 @@
 package com.oasisfeng.common.app;
 
-import android.databinding.BaseObservable;
-import android.databinding.ObservableBoolean;
+import android.arch.lifecycle.ViewModel;
 import android.databinding.ObservableField;
 import android.graphics.drawable.Drawable;
 import android.text.TextUtils;
 import android.view.View;
 
 import com.oasisfeng.android.ui.IconResizer;
+import com.oasisfeng.androidx.lifecycle.NonNullMutableLiveData;
+import com.oasisfeng.island.IslandApplication;
+import com.oasisfeng.island.mobile.R;
 
 import static android.content.pm.ApplicationInfo.FLAG_SYSTEM;
 
@@ -16,11 +18,11 @@
  *
  * Created by Oasis on 2016/8/11.
  */
-public class BaseAppViewModel extends BaseObservable {
+public class BaseAppViewModel extends ViewModel {
 
 	public final AppInfo info;
-	public final ObservableField<Drawable> icon = new ObservableField<>();
-	public transient final ObservableBoolean selected = new ObservableBoolean(false);
+	public final ObservableField<Drawable> icon = new ObservableField<>();		// Issue in data-binding - MutableLiveData causes initially empty icons.
+	public transient final NonNullMutableLiveData<Boolean> selected = new NonNullMutableLiveData<>(false);
 	private volatile boolean mIconLoadingStarted;
 
 	public boolean isSystem() { return (info.flags & FLAG_SYSTEM) != 0; }
@@ -44,6 +46,5 @@ protected boolean isContentSameAs(final BaseAppViewModel another) {
 		return TextUtils.equals(info.getLabel(), another.info.getLabel());
 	}
 
-
-	private final static IconResizer sIconResizer = new IconResizer();		// TODO: Avoid static
+	private final static IconResizer sIconResizer = new IconResizer((int) IslandApplication.$().getResources().getDimension(R.dimen.app_icon_size));	// TODO: Avoid static
 }

app/src/main/java/com/oasisfeng/island/MainActivity.java

@@ -1,6 +1,5 @@
 package com.oasisfeng.island;
 
-import android.app.Activity;
 import android.app.admin.DevicePolicyManager;
 import android.content.ComponentName;
 import android.content.Context;
@@ -13,6 +12,7 @@
 import android.os.Bundle;
 import android.os.SystemClock;
 import android.os.UserHandle;
+import android.support.v4.app.FragmentActivity;
 import android.util.Log;
 
 import com.oasisfeng.android.base.Scopes;
@@ -35,7 +35,7 @@
 import static android.content.pm.PackageManager.COMPONENT_ENABLED_STATE_DISABLED;
 import static android.content.pm.PackageManager.DONT_KILL_APP;
 
-public class MainActivity extends Activity {
+public class MainActivity extends FragmentActivity {
 
 	@Override protected void onCreate(final Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
@@ -103,7 +103,7 @@ private void onCreateInProfile() {
 	private void startMainUi(final Bundle savedInstanceState) {
 		setContentView(R.layout.activity_main);
 		if (savedInstanceState != null) return;
-		getFragmentManager().beginTransaction().replace(R.id.container, new AppListFragment()).commit();
+		getSupportFragmentManager().beginTransaction().replace(R.id.container, new AppListFragment()).commit();
 		performOverallAnalyticsIfNeeded();
 	}
 

app/src/main/java/com/oasisfeng/island/console/apps/AppListFragment.java

@@ -3,16 +3,15 @@
 import android.annotation.SuppressLint;
 import android.app.ActionBar;
 import android.app.Activity;
-import android.app.Fragment;
 import android.app.admin.DevicePolicyManager;
+import android.arch.lifecycle.ViewModelProviders;
 import android.content.ActivityNotFoundException;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
-import android.databinding.Observable;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Environment;
@@ -21,6 +20,8 @@
 import android.provider.DocumentsContract;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentActivity;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -45,7 +46,6 @@
 import com.oasisfeng.island.engine.IIslandManager;
 import com.oasisfeng.island.engine.IslandManager;
 import com.oasisfeng.island.guide.UserGuide;
-import com.oasisfeng.island.mobile.BR;
 import com.oasisfeng.island.mobile.BuildConfig;
 import com.oasisfeng.island.mobile.R;
 import com.oasisfeng.island.mobile.databinding.AppListBinding;
@@ -62,8 +62,11 @@
 
 import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.ExecutionException;
 
+import javax.annotation.ParametersAreNonnullByDefault;
+
 import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;
 import static android.content.Context.BIND_AUTO_CREATE;
 import static android.content.Intent.ACTION_OPEN_DOCUMENT;
@@ -79,14 +82,15 @@
 import static com.oasisfeng.island.analytics.Analytics.Param.ITEM_ID;
 
 /** The main UI - App list */
+@ParametersAreNonnullByDefault
 public class AppListFragment extends Fragment {
 
-	@Override public void onCreate(final Bundle savedInstanceState) {
+	@Override public void onCreate(final @Nullable Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		setHasOptionsMenu(true);
-		final Activity activity = getActivity();
+		final FragmentActivity activity = getActivity();
 		mShuttleContext = new ShuttleContext(activity);
-		mViewModel = new AppListViewModel();
+		mViewModel = ViewModelProviders.of(this).get(AppListViewModel.class);
 		mViewModel.mProfileController = IslandManager.NULL;
 		mUserGuide = UserGuide.initializeIfNeeded(activity, mViewModel);
 		IslandAppListProvider.getInstance(activity).registerObserver(mAppChangeObserver);
@@ -115,7 +119,6 @@ public class AppListFragment extends Fragment {
 
 	@Override public void onDestroy() {
 		IslandAppListProvider.getInstance(getActivity()).unregisterObserver(mAppChangeObserver);
-		mViewModel.removeOnPropertyChangedCallback(onPropertyChangedCallback);
 		super.onDestroy();
 	}
 
@@ -155,22 +158,19 @@ public class AppListFragment extends Fragment {
 		}
 	};
 
-	private final Observable.OnPropertyChangedCallback onPropertyChangedCallback = new Observable.OnPropertyChangedCallback() { @Override public void onPropertyChanged(final Observable observable, final int var) {
-		if (var == BR.selection) invalidateOptionsMenu();
-	}};
-
 	private void invalidateOptionsMenu() {
 		final Activity activity = getActivity();
 		if (activity != null) activity.invalidateOptionsMenu();
 	}
 
-	@Nullable @Override public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final @Nullable Bundle saved_state) {
-		final Activity activity = getActivity();
+	@Nullable @Override public View onCreateView(final LayoutInflater inflater, final @Nullable ViewGroup container, final @Nullable Bundle saved_state) {
+		final Activity activity = Objects.requireNonNull(getActivity());
 		mBinding = AppListBinding.inflate(inflater, container, false);
 		mBinding.setApps(mViewModel);
 		mBinding.setGuide(mUserGuide);
+		mBinding.setLifecycleOwner(this);
 		mViewModel.attach(activity, mBinding.details.toolbar.getMenu(), saved_state);
-		mViewModel.addOnPropertyChangedCallback(onPropertyChangedCallback);
+		mViewModel.mSelection.observe(this, selection -> invalidateOptionsMenu());
 
 		if (! Services.bind(activity, IIslandManager.class, mIslandManagerConnection = new ServiceConnection() {
 			@Override public void onServiceConnected(final ComponentName name, final IBinder service) {
@@ -186,7 +186,7 @@ private void invalidateOptionsMenu() {
 		mBinding.filters.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 			@Override public void onItemSelected(final AdapterView<?> parent, final View view, final int position, final long id) {
 				if (getActivity() == null) return;
-				mViewModel.setFilterPrimaryChoice(position);
+				mViewModel.mFilterPrimaryChoice.setValue(position);
 			}
 			@Override public void onNothingSelected(final AdapterView<?> parent) {}
 		});
@@ -196,7 +196,8 @@ private void invalidateOptionsMenu() {
 
 	@Override public void onDestroyView() {
 		if (mIslandManagerConnection != null) {
-			getActivity().unbindService(mIslandManagerConnection);
+			final FragmentActivity activity = getActivity();
+			if (activity != null) activity.unbindService(mIslandManagerConnection);
 			mIslandManagerConnection = null;
 		}
 		super.onDestroyView();
@@ -210,7 +211,7 @@ private void invalidateOptionsMenu() {
 		final Context context = getActivity();
 		final MenuItem.OnMenuItemClickListener tip = mUserGuide == null ? null : mUserGuide.getAvailableTip();
 		menu.findItem(R.id.menu_tip).setVisible(tip != null).setOnMenuItemClickListener(tip);
-		menu.findItem(R.id.menu_search).setVisible(mViewModel.getSelection() == null).setOnActionExpandListener(mOnActionExpandListener);
+		menu.findItem(R.id.menu_search).setVisible(mViewModel.mSelection.getValue() == null).setOnActionExpandListener(mOnActionExpandListener);
 		menu.findItem(R.id.menu_files).setVisible(context != null && Users.hasProfile() &&
 				(! Permissions.has(context, WRITE_EXTERNAL_STORAGE) || findFileBrowser(context) != null));
 		menu.findItem(R.id.menu_show_system).setChecked(mViewModel.areSystemAppsIncluded());
@@ -252,7 +253,7 @@ private void invalidateOptionsMenu() {
 	}
 
 	private void requestPermissionAndLaunchFilesExplorerInIsland() {
-		final Context context = getActivity();
+		final Context context = Objects.requireNonNull(getActivity());
 		if (context.checkPermission(WRITE_EXTERNAL_STORAGE, Process.myPid(), Process.myUid()) == PERMISSION_GRANTED) {
 			final ListenableFuture<Boolean> future = MethodShuttle.runInProfile(context, () -> {
 				final Intent intent = findFileBrowser(context);

app/src/main/java/com/oasisfeng/island/guide/UserGuide.java

@@ -1,11 +1,12 @@
 package com.oasisfeng.island.guide;
 
 import android.app.Activity;
+import android.arch.lifecycle.Observer;
 import android.databinding.BindingAdapter;
-import android.databinding.Observable;
 import android.databinding.ObservableField;
 import android.support.annotation.Nullable;
 import android.support.annotation.StringRes;
+import android.support.v4.app.FragmentActivity;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
@@ -16,7 +17,6 @@
 import com.oasisfeng.common.app.AppListProvider;
 import com.oasisfeng.island.data.IslandAppInfo;
 import com.oasisfeng.island.data.IslandAppListProvider;
-import com.oasisfeng.island.mobile.BR;
 import com.oasisfeng.island.mobile.R;
 import com.oasisfeng.island.model.AppListViewModel;
 import com.oasisfeng.island.model.AppListViewModel.Filter;
@@ -92,26 +92,24 @@ private static View findProperTarget(final View view) {
 		return view;
 	}
 
-	public static @Nullable UserGuide initializeIfNeeded(final Activity activity, final AppListViewModel vm) {
+	public static @Nullable UserGuide initializeIfNeeded(final FragmentActivity activity, final AppListViewModel vm) {
 		final Scopes.Scope scope = Scopes.app(activity);
 
-		final boolean action_tips_pending = UserGuide.anyActionTipPending(scope);
+		final boolean action_tips_pending = anyActionTipPending(scope);
 		if (! action_tips_pending && scope.isMarked(SCOPE_KEY_TIP_FILTER)) return null;
 		final UserGuide guide = new UserGuide(activity, scope);
 
-		vm.addOnPropertyChangedCallback(new Observable.OnPropertyChangedCallback() { @Override public void onPropertyChanged(final Observable sender, final int property) {
-			if (property == BR.filterPrimaryChoice) {
-				final AppListViewModel vm = (AppListViewModel) sender;
-				final Filter filter = vm.getFilterPrimaryOptions().get(vm.getFilterPrimaryChoice()).parent();
-				if (guide.mFilter != null && filter != guide.mFilter) {
-					scope.markOnly(SCOPE_KEY_TIP_FILTER);				// User just switched filter, no need to show tip for filter switching.
-					activity.invalidateOptionsMenu();
-					if (! UserGuide.anyActionTipPending(scope))
-						vm.removeOnPropertyChangedCallback(this);	// No need to monitor filter or selection any more.
-				}
-				guide.mFilter = filter;
-			} else if (property == BR.selection) guide.mAppSelection = ((AppListViewModel) sender).getSelection();
+		vm.mFilterPrimaryChoice.observe(activity, new Observer<Integer>() { @Override public void onChanged(final Integer choice) {
+			final Filter filter = vm.mFilterPrimaryOptions.getValue().get(choice).parent();
+			if (guide.mFilter != null && filter != guide.mFilter) {
+				scope.markOnly(SCOPE_KEY_TIP_FILTER);                // User just switched filter, no need to show tip for filter switching.
+				activity.invalidateOptionsMenu();
+				if (! anyActionTipPending(scope))
+					vm.mFilterPrimaryChoice.removeObserver(this);    // No need to monitor filter or selection any more.
+			}
+			guide.mFilter = filter;
 		}});
+		vm.mSelection.observe(activity, selection -> guide.mAppSelection = selection);
 		if (action_tips_pending) {
 			final IslandAppListProvider provider = IslandAppListProvider.getInstance(activity);
 			provider.registerObserver(new AppListProvider.PackageChangeObserver<IslandAppInfo>() {