Why doesn't my Tween animation work?

Question

I have a feeling I'm going to be using this site a lot. As I move through this project I feel like I'm using you guys as a crutch, but good lord are you great at helping me. Here's my current issue:

My app has TabSwype navigation and fragments. The main fragment has an ImageView and a Button, You press the button and a Tween animation takes place. Simple right?

I've got it all in place to where it won't crash on me, and the tween does NOTHING. SO frustrating. Here's my code.

Main Fragment:

package edu.wmich.lab4_jjohns1119;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.view.animation.AnimationUtils;
import android.view.animation.Animation;

public class MainFragment extends Fragment {

//Declare widget objects
Button btnAnimate;
ImageView imgTween;
Animation tweenAnimation;

//create view
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

//Inflater
View rootView = inflater.inflate(R.layout.fragment_main, container,false);
//Button
     btnAnimate = (Button)rootView.findViewById(R.id.btnAnimate);   
     //Image
     imgTween = (ImageView)rootView.findViewById(R.id.imgTween);
     //Animation Resource
    tweenAnimation = AnimationUtils.loadAnimation(getActivity(), R.anim.tween1);
//Button listener for animation
btnAnimate.setOnClickListener(new View.OnClickListener(){

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        //animate image
        imgTween.startAnimation(tweenAnimation);
    }

});
//Return view
return rootView;
}
}

fragment_main.XML:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<Button
    android:id="@+id/btnAnimate"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="36dp"
    android:text="@string/button_text_animate" />

<ImageView
    android:id="@+id/imgTween"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="39dp"
    android:src="@drawable/android_logo" />

</RelativeLayout>

And my Tween.XML:

<?xml version="1.0" encoding="utf-8"?>
<rotate
xmlns:android="http//schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:toDegrees="-45"
android:duration="400"
 />

Answer 1

You don't have your animation within a <set>. You also need to provide an interpolator for your animation. Try changing your xml to this:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/linear_interpolator" >
    <rotate
        android:fromDegrees="0"
        android:toDegrees="-45"
        android:duration="400" />
</set>