ProfileList: Add minimal activity

For now, it simply reads the files in the app's data directory with
file names ending in ".conf" and displays them in a list.

This includes the generic list data binding setup for future use.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/BindingAdapters.java

@@ -0,0 +1,38 @@
+package com.wireguard.android;
+
+import android.databinding.BindingAdapter;
+import android.databinding.ObservableList;
+import android.widget.ListView;
+
+/**
+ * Static methods for use by generated code in the Android data binding library.
+ */
+
+public final class BindingAdapters {
+    @BindingAdapter({"items", "layout"})
+    public static <T> void listBinding(ListView view, ObservableList<T> oldList, int oldLayoutId,
+                                       ObservableList<T> newList, int newLayoutId) {
+        // Remove any existing binding when there is no new list.
+        if (newList == null) {
+            view.setAdapter(null);
+            return;
+        }
+        // The ListAdapter interface is not generic, so this cannot be checked.
+        @SuppressWarnings("unchecked")
+        ObservableListAdapter<T> adapter = (ObservableListAdapter<T>) view.getAdapter();
+        // If the layout changes, any existing adapter must be replaced.
+        if (newLayoutId != oldLayoutId)
+            adapter = null;
+        // Add a new binding if there was none, or if it must be replaced due to a layout change.
+        if (adapter == null) {
+            adapter = new ObservableListAdapter<>(view.getContext(), newLayoutId, newList);
+            view.setAdapter(adapter);
+        } else if (newList != oldList) {
+            // Changing the list only requires modifying the existing adapter.
+            adapter.setList(newList);
+        }
+    }
+
+    private BindingAdapters() {
+    }
+}

app/src/main/java/com/wireguard/android/ObservableListAdapter.java

@@ -0,0 +1,91 @@
+package com.wireguard.android;
+
+import android.content.Context;
+import android.databinding.DataBindingUtil;
+import android.databinding.ObservableList;
+import android.databinding.ViewDataBinding;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.ListAdapter;
+
+/**
+ * A generic ListAdapter backed by an ObservableList.
+ */
+
+class ObservableListAdapter<T> extends BaseAdapter implements ListAdapter {
+    private final int layoutId;
+    private final LayoutInflater layoutInflater;
+    private ObservableList<T> list;
+    private final OnListChangedCallback<ObservableList<T>> callback = new OnListChangedCallback<>();
+
+    ObservableListAdapter(Context context, int layoutId, ObservableList<T> list) {
+        this.layoutInflater = LayoutInflater.from(context);
+        this.layoutId = layoutId;
+        setList(list);
+    }
+
+    @Override
+    public int getCount() {
+        return list != null ? list.size() : 0;
+    }
+
+    @Override
+    public T getItem(int position) {
+        return list != null ? list.get(position) : null;
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return position;
+    }
+
+    @Override
+    public View getView(int position, View convertView, ViewGroup parent) {
+        ViewDataBinding binding = DataBindingUtil.getBinding(convertView);
+        if (binding == null)
+            binding = DataBindingUtil.inflate(layoutInflater, layoutId, parent, false);
+        binding.setVariable(BR.item, getItem(position));
+        binding.executePendingBindings();
+        return binding.getRoot();
+    }
+
+    public void setList(ObservableList<T> newList) {
+        if (list != null)
+            list.removeOnListChangedCallback(callback);
+        list = newList;
+        if (list != null) {
+            list.addOnListChangedCallback(callback);
+        }
+    }
+
+    private class OnListChangedCallback<L extends ObservableList<T>>
+            extends ObservableList.OnListChangedCallback<L> {
+        @Override
+        public void onChanged(L sender) {
+            ObservableListAdapter.this.notifyDataSetChanged();
+        }
+
+        @Override
+        public void onItemRangeChanged(L sender, int positionStart, int itemCount) {
+            ObservableListAdapter.this.notifyDataSetChanged();
+        }
+
+        @Override
+        public void onItemRangeInserted(L sender, int positionStart, int itemCount) {
+            ObservableListAdapter.this.notifyDataSetChanged();
+        }
+
+        @Override
+        public void onItemRangeMoved(L sender, int fromPosition, int toPosition,
+                                     int itemCount) {
+            ObservableListAdapter.this.notifyDataSetChanged();
+        }
+
+        @Override
+        public void onItemRangeRemoved(L sender, int positionStart, int itemCount) {
+            ObservableListAdapter.this.notifyDataSetChanged();
+        }
+    }
+}

app/src/main/java/com/wireguard/android/ProfileListActivity.java

@@ -0,0 +1,64 @@
+package com.wireguard.android;
+
+import android.app.Activity;
+import android.databinding.DataBindingUtil;
+import android.databinding.ObservableArrayList;
+import android.databinding.ObservableList;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.util.Log;
+
+import com.wireguard.android.databinding.ProfileListActivityBinding;
+import com.wireguard.config.Profile;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+
+public class ProfileListActivity extends Activity {
+    private final ObservableList<Profile> profiles = new ObservableArrayList<>();
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        final ProfileListActivityBinding binding =
+                DataBindingUtil.setContentView(this, R.layout.profile_list_activity);
+        binding.setProfiles(profiles);
+        new ProfileLoader().execute(getFilesDir().listFiles());
+    }
+
+    private class ProfileLoader extends AsyncTask<File, Profile, ArrayList<Profile>> {
+        private static final String TAG = "WGProfileLoader";
+
+        @Override
+        protected ArrayList<Profile> doInBackground(File... files) {
+            final ArrayList<Profile> loadedProfiles = new ArrayList<>();
+            for (File file : files) {
+                final String fileName = file.getName();
+                final int suffixStart = fileName.lastIndexOf(".conf");
+                if (suffixStart <= 0) {
+                    Log.w(TAG, "Ignoring stray file " + fileName);
+                    continue;
+                }
+                final Profile profile = new Profile(fileName.substring(0, suffixStart));
+                try {
+                    final FileInputStream inputStream = openFileInput(fileName);
+                    profile.fromStream(inputStream);
+                    loadedProfiles.add(profile);
+                } catch (IOException e) {
+                    Log.w(TAG, "Failed to load profile from " + fileName, e);
+                }
+                if (isCancelled())
+                    break;
+            }
+            return loadedProfiles;
+        }
+
+        @Override
+        protected void onPostExecute(ArrayList<Profile> loadedProfiles) {
+            // FIXME: This should replace an existing profile if the name matches.
+            profiles.addAll(loadedProfiles);
+        }
+    }
+}