Forum Avatars using the first letter of the forum and color from group

Also prevents the snackbar from hiding the bottom of the list.

Closes #337

briar-android/src/org/briarproject/android/util/BriarRecyclerViewBehavior.java

@@ -0,0 +1,44 @@
+package org.briarproject.android.util;
+
+import android.content.Context;
+import android.support.design.widget.CoordinatorLayout;
+import android.support.design.widget.Snackbar;
+import android.util.AttributeSet;
+import android.view.View;
+
+public class BriarRecyclerViewBehavior
+		extends CoordinatorLayout.Behavior<BriarRecyclerView> {
+
+	public BriarRecyclerViewBehavior(Context context, AttributeSet attrs) {
+		super(context, attrs);
+	}
+
+	@Override
+	public boolean onDependentViewChanged(CoordinatorLayout parent,
+			BriarRecyclerView child, View dependency) {
+
+		// FIXME the below code works, but does not reset margin when snackbar is dismissed
+/*
+		int margin = 0;
+		if (dependency.isShown()) margin = dependency.getHeight();
+
+		// set snackbar height as bottom margin if it is shown
+		CoordinatorLayout.LayoutParams params =
+				(CoordinatorLayout.LayoutParams) child.getLayoutParams();
+		params.setMargins(0, 0, 0, margin);
+		child.setLayoutParams(params);
+
+		child.scrollToPosition(0);
+*/
+		return true;
+	}
+
+	@Override
+	public boolean layoutDependsOn(CoordinatorLayout parent,
+			BriarRecyclerView child, View dependency) {
+		// we only want to trigger the change
+		// only when the changes is from a snackbar
+		return dependency instanceof Snackbar.SnackbarLayout;
+	}
+
+}

briar-android/src/org/briarproject/android/util/TextAvatarView.java

@@ -0,0 +1,57 @@
+package org.briarproject.android.util;
+
+import android.content.Context;
+import android.content.res.ColorStateList;
+import android.graphics.Color;
+import android.graphics.PorterDuff;
+import android.support.v7.widget.AppCompatTextView;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.widget.FrameLayout;
+
+import org.briarproject.R;
+
+import de.hdodenhof.circleimageview.CircleImageView;
+
+public class TextAvatarView extends FrameLayout {
+
+	final private AppCompatTextView textView;
+	final private CircleImageView backgroundView;
+
+	public TextAvatarView(Context context, AttributeSet attrs) {
+		super(context, attrs);
+
+		LayoutInflater inflater = (LayoutInflater) context
+				.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+		inflater
+				.inflate(R.layout.text_avatar_view, this, true);
+		textView = (AppCompatTextView) findViewById(R.id.textAvatarView);
+		backgroundView = (CircleImageView) findViewById(R.id.avatarBackground);
+	}
+
+	public TextAvatarView(Context context) {
+		this(context, null);
+	}
+
+	public void setText(String text) {
+		textView.setText(text);
+	}
+
+	public void setBackgroundBytes(byte[] bytes) {
+		int r = getByte(bytes, 0) * 3 / 4 + 96;
+		int g = getByte(bytes, 1) * 3 / 4 + 96;
+		int b = getByte(bytes, 2) * 3 / 4 + 96;
+		int color = Color.rgb(r, g, b);
+
+		backgroundView.setFillColor(color);
+	}
+
+	private byte getByte(byte[] bytes, int index) {
+		if (bytes == null) {
+			return -128;
+		} else {
+			return bytes[index % bytes.length];
+		}
+	}
+
+}