Add empty state for conversation list

src/org/thoughtcrime/securesms/components/registration/PulsingFloatingActionButton.java

@@ -0,0 +1,55 @@
+package org.thoughtcrime.securesms.components.registration;
+
+
+import android.animation.Animator;
+import android.content.Context;
+import android.support.design.widget.FloatingActionButton;
+import android.util.AttributeSet;
+
+import org.thoughtcrime.securesms.animation.AnimationCompleteListener;
+
+public class PulsingFloatingActionButton extends FloatingActionButton {
+
+  private boolean pulsing;
+
+  public PulsingFloatingActionButton(Context context) {
+    super(context);
+  }
+
+  public PulsingFloatingActionButton(Context context, AttributeSet attrs) {
+    super(context, attrs);
+  }
+
+  public PulsingFloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr) {
+    super(context, attrs, defStyleAttr);
+  }
+
+  public void startPulse(long periodMillis) {
+    if (!pulsing) {
+      pulsing = true;
+      pulse(periodMillis);
+    }
+  }
+
+  public void stopPulse() {
+    pulsing = false;
+  }
+
+  private void pulse(long periodMillis) {
+    if (!pulsing) return;
+
+    this.animate().scaleX(1.2f).scaleY(1.2f).setDuration(150).setListener(new AnimationCompleteListener() {
+      @Override
+      public void onAnimationEnd(Animator animation) {
+        clearAnimation();
+        animate().scaleX(1.0f).scaleY(1.0f).setDuration(150).setListener(new AnimationCompleteListener() {
+          @Override
+          public void onAnimationEnd(Animator animation) {
+            PulsingFloatingActionButton.this.postDelayed(() -> pulse(periodMillis), periodMillis);
+          }
+        }).start();
+      }
+    }).start();
+  }
+
+}