fragment 中的 Android 动画不起作用

Question

我有三个重叠的 ScrollView 。出于某种原因，当我将另外两个设置为 View.Gone 并将一个 ScrollView 设置为 View.Visible，然后启动动画时，它不会被触发。这些 ScrollView 在一个 fragment 中——我知道有些功能在一个 fragment 中不能完全工作。虽然动画看起来很基本。

这是我的按钮监听器的方法；

        sv2.setVisibility(View.GONE);
        sv3.setVisibility(View.GONE);
        sv1.setVisibility(View.VISIBLE);
        Animation fadeInAnimation = AnimationUtils.loadAnimation(getActivity(), R.anim.fade_in_scollview);
        //set your animation
        sv1.startAnimation(fadeInAnimation);

也尝试过设置不可见，加载动画，然后使其可见；

        sv1.setVisibility(View.INVISIBLE);
        Animation fadeInAnimation = AnimationUtils.loadAnimation(getActivity(), R.anim.fade_in_scollview);  
        //set your animation
        sv1.startAnimation(fadeInAnimation);
        sv1.setVisibility(View.VISIBLE);

这是我的动画 xml；

<?xml version="1.0" encoding="UTF-8"?>
  <set xmlns:android="http://schemas.android.com/apk/res/android">
    <alpha android:fromAlpha="0.0" android:toAlpha="1.0" 
     android:interpolator="@android:anim/accelerate_interpolator" 
   android:duration="500"
    android:repeatCount="infinite"/>
 </set>

Answer 1

要在 Fragment 中使用动画，请尝试以下代码

这是我的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/iv_banner"
        android:layout_width="fill_parent"
        android:layout_height="250dp"
        android:layout_gravity="center_horizontal" />
</LinearLayout>

这是我的 fragment java类

    public class Fragment_Home extends Fragment {
    public int currentimageindex = 0;
    Handler mHandler = new Handler();
    Runnable mUpdateResults;

    //Array of drawable images
    private int[] IMAGE_IDS = {
            R.drawable.home_slider_stemer, R.drawable.home_slider_plane
    };

    //image view
    private ImageView iv_banner;
    private View rootView;

    public Fragment_Home() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        rootView = inflater.inflate(R.layout.fragment_home, container, false);

        LoadUIElements();



        return rootView;
    }

    private void LoadUIElements() {
        iv_banner = (ImageView) rootView.findViewById(R.id.iv_banner);
        int delay = 1000; // delay for 1 sec.

        int period = 2000; // repeat every 4 sec.
        Timer timer = new Timer();

        timer.scheduleAtFixedRate(new TimerTask() {

            @Override
            public void run() {
                // TODO Auto-generated method stub
                mHandler.post(mUpdateResults);
            }
        }, delay, period);

        mUpdateResults = new Runnable() {
            @Override
            public void run() {
                // TODO Auto-generated method stub
                try {
                    AnimateandSlideShow();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        };
    }

    /**
     * Helper method to start the animation on the splash screen
     */
    protected void AnimateandSlideShow() {
        // TODO Auto-generated method stub
        try {
            iv_banner.setImageResource(IMAGE_IDS[currentimageindex
                    % IMAGE_IDS.length]);

            currentimageindex++;
            Animation rotateimage = AnimationUtils.loadAnimation(getActivity()
                    .getBaseContext().getApplicationContext(), R.anim.fade_in);
            iv_banner.startAnimation(rotateimage);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

不要忘记将图像放在 res 中的 Drawable 文件夹中。