Hold to dismiss, for trikita#20

Instead of dismissing instantly on touch, instead the touch must be held
down for 2 seconds. During this time, the background will fade to be the
same color as the alarm icon, giving a progress indicator.

While holding, the icon will also change to a finger (touch_app), to
provide a hint about what you need to do. This is an effective hint
because tapping makes it flicker, and if you hold for long enough to see
what the new icon is, you'll also hold for long enough that the
background will start fading, giving you the next hint.

Pressing the home or back button will still dismiss instantly, since
there's no way to track touches on those.

src/main/java/trikita/talalarmo/alarm/AlarmActivity.java

@@ -1,14 +1,19 @@
 package trikita.talalarmo.alarm;
 
+import android.animation.AnimatorListenerAdapter;
+import android.animation.ArgbEvaluator;
+import android.animation.ValueAnimator;
 import android.app.Activity;
 import android.content.Context;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.PowerManager;
+import android.view.MotionEvent;
 import android.view.Window;
 import android.view.WindowManager;
 
 import trikita.anvil.RenderableView;
+import trikita.anvil.Anvil;
 import static trikita.anvil.DSL.*;
 
 import trikita.jedux.Action;
@@ -19,6 +24,10 @@
 
 public class AlarmActivity extends Activity {
     private PowerManager.WakeLock mWakeLock;
+    private ValueAnimator mAnimator;
+    private int bgColor;
+    private String txt;
+    private boolean canceled;
 
     @Override
     protected void onCreate(Bundle b) {
@@ -37,15 +46,59 @@ protected void onCreate(Bundle b) {
             window.setStatusBarColor(Theme.get(App.getState().settings().theme()).primaryDarkColor);
         }
 
+        txt = "\ue857"; // alarm_off icon
+        int colorFrom = Theme.get(App.getState().settings().theme()).backgroundColor;
+        int colorTo = Theme.get(App.getState().settings().theme()).accentColor;
+        bgColor = colorFrom;
+        mAnimator = ValueAnimator.ofObject(new ArgbEvaluator(), colorFrom, colorTo);
+        mAnimator.setDuration(2000); // millis
+        mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
+            @Override
+            public void onAnimationUpdate(ValueAnimator animator) {
+                bgColor = (int) animator.getAnimatedValue();
+                Anvil.render();
+            }
+        });
+        mAnimator.addListener(new AnimatorListenerAdapter() {
+            @Override
+            public void onAnimationStart(Animator animator) {
+                canceled = false;
+                txt = "\ue913"; // touch_app icon
+            }
+            @Override
+            public void onAnimationCancel(Animator animator) {
+                canceled = true;
+                txt = "\ue857"; // alarm_off icon
+                bgColor = colorFrom;
+                Anvil.render();
+            }
+            @Override
+            public void onAnimationEnd(Animator animator) {
+                if (!canceled) {
+                    stopAlarm();
+                }
+            }
+        });
+
         setContentView(new RenderableView(this) {
             public void view() {
                 Theme.materialIcon(() -> {
                     size(FILL, FILL);
-                    text("\ue857"); // "alarm off"
+                    text(txt);
                     textColor(Theme.get(App.getState().settings().theme()).accentColor);
                     textSize(dip(128));
-                    backgroundColor(Theme.get(App.getState().settings().theme()).backgroundColor);
-                    onClick(v -> stopAlarm());
+                    backgroundColor(bgColor);
+                    onTouch((v, e) -> {
+                        if(e.getAction() == MotionEvent.ACTION_DOWN){
+                            mAnimator.start();
+                            return true;
+                        }
+                        if(e.getAction() == MotionEvent.ACTION_UP){
+                            mAnimator.cancel();
+                            return true;
+                        }
+                        return false;
+                    });
                 });
             }
         });