android - sharedElment 过渡使用不过渡的 fragment

Question

AndroidStudio 2.3 Beta 1

我正在尝试让过渡与 fragment 一起工作，但我使用的图像如何不过渡。它只是正常弹出。

我已经创建了一个简单的应用程序来尝试让它工作。我有 2 个 fragment ListMovieFragment 和 DetailMovieFragment。和 1 个 MainActivity。

用户将单击 ListMovieFragment 中的图像以转换到 DetailMovieFragment。

这是我的转换 xml change_image_transform:

<?xml version="1.0" encoding="utf-8"?>
<transitionSet xmlns:android="http://schemas.android.com/apk/res/android">
    <changeImageTransform/>
</transitionSet>

列表电影 fragment :

public class ListMovieFragment extends Fragment {
    public interface MovieSelectedListener {
        void onMovieSelected(int movieId);
    }
    private MovieSelectedListener mMovieSelectedListener;

    public ListMovieFragment() {
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mMovieSelectedListener = (MovieSelectedListener)context;
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mMovieSelectedListener = null;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        final View view = inflater.inflate(R.layout.fragment_list, container, false);
        final ImageView ivMoviePoster = (ImageView)view.findViewById(R.id.ivMoviePoster);

        ivMoviePoster.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mMovieSelectedListener != null) {
                    mMovieSelectedListener.onMovieSelected(12345);
                }
            }
        });

        Glide.with(getActivity())
                .load("https://image.tmdb.org/t/p/w185/qjiskwlV1qQzRCjpV0cL9pEMF9a.jpg")
                .placeholder(R.drawable.placeholder_poster)
                .centerCrop()
                .crossFade()
                .into(ivMoviePoster);

        return view;
    }
}

详细电影 fragment

public class DetailMovieFragment extends Fragment {
    public DetailMovieFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        final View view = inflater.inflate(R.layout.fragment_detail, container, false);

        final ImageView ivMovieDetailPoster = (ImageView)view.findViewById(R.id.ivMovieDetailPoster);

        Glide.with(getActivity())
                .load("https://image.tmdb.org/t/p/w185/qjiskwlV1qQzRCjpV0cL9pEMF9a.jpg")
                .placeholder(R.drawable.placeholder_poster)
                .centerCrop()
                .crossFade()
                .into(ivMovieDetailPoster);

        return view;
    }
}

主要 Activity

public class MainActivity extends AppCompatActivity implements ListMovieFragment.MovieSelectedListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if(savedInstanceState == null) {
            FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            fragmentTransaction.add(R.id.activity_main, new ListMovieFragment(), "listmoviefragment");
            fragmentTransaction.commit();
        }
    }

    @Override
    public void onMovieSelected(int movieId) {
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            /* Get the fragments that will be using the transition */
            ListMovieFragment listMovieFragment = new ListMovieFragment();
            DetailMovieFragment detailMovieFragment = new DetailMovieFragment();

            /* Inflate the transition */
            Transition changeTransition = TransitionInflater
                    .from(MainActivity.this)
                    .inflateTransition(R.transition.change_image_transform);

            Transition explodeTransition = TransitionInflater
                    .from(MainActivity.this)
                    .inflateTransition(android.R.transition.explode);

            /* Set the exit and return on the source fragment (ListMovieFragment) */
            listMovieFragment.setSharedElementReturnTransition(changeTransition);
            listMovieFragment.setExitTransition(explodeTransition);

            /* Set the enter on the destination fragment (MovieDetailFragment) */
            detailMovieFragment.setSharedElementEnterTransition(changeTransition);
            detailMovieFragment.setEnterTransition(explodeTransition);

            /* Get the shared imageview from the source fragment (MovieListFragment) */
            final ImageView ivSharedImage = (ImageView)findViewById(R.id.ivMoviePoster);

            FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.activity_main, new DetailMovieFragment(), "detailmoviefragment");
            fragmentTransaction.addToBackStack("detailmoviefragment");
            fragmentTransaction.addSharedElement(ivSharedImage, getResources().getString(R.string.transition_poster_image));
            fragmentTransaction.commit();
        }
        else {
            FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.activity_main, new DetailMovieFragment(), "detailmoviefragment");
            fragmentTransaction.addToBackStack("detailmoviefragment");
            fragmentTransaction.commit();
        }
    }

    @Override
    public void onBackPressed() {
        if(getSupportFragmentManager().getBackStackEntryCount() > 0) {
            getSupportFragmentManager().popBackStackImmediate();
        }
        else {
            super.onBackPressed();
        }
    }
}

ListMovieFragment 的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingBottom="6dp">

    <ImageView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/ivMoviePoster"
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:src="@drawable/placeholder_poster"
        android:scaleType="fitXY"
        android:adjustViewBounds="true"
        android:transitionName="@string/transition_poster_image">
    </ImageView>
</LinearLayout>

DetailMovieFragment 的布局:

<FrameLayout 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"
    tools:context="me.androidbox.fragmenttransitions.detail.DetailMovieFragment">
    <ImageView
        android:id="@+id/ivMovieDetailPoster"
        android:layout_width="140dp"
        android:layout_height="160dp"
        android:layout_marginEnd="16dp"
        android:layout_marginTop="112dp"
        android:adjustViewBounds="true"
        android:scaleType="fitXY"
        android:layout_gravity="end"
        android:transitionName="@string/transition_poster_image"/>
</FrameLayout>

转换名称的字符串名称:

<string name="transition_poster_image">imagePoster</string>

实现看起来很简单，所以我认为我忽略了一些错误。

非常感谢您的任何建议，

Answer 1

您的代码中有两个问题，在您的 onMovieSelected 方法中:

1. 您正在创建 ListMovieFragment 的新实例，然后对其应用转换逻辑。但是您忘记了您已经拥有该 fragment 的实例(您是在 onCreate 方法中创建的)。因此，您需要从 FragmentManager 中检索现有的 ListMovieFragment 对象，并将您的过渡应用到它。
2. 您正在将转换逻辑应用于 DetailMovieFragment 的一个实例，但随后突然将 ListMoveFragment 替换为新实例。

所以你固定的 onMovieSelected 方法将是:

@Override
public void onMovieSelected(int movieId) {
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        /* Get the fragments that will be using the transition */
        ListMovieFragment listMovieFragment = (ListMovieFragment) getSupportFragmentManager().findFragmentByTag("listmoviefragment");
        DetailMovieFragment detailMovieFragment = new DetailMovieFragment();

        /* Inflate the transition */
        Transition changeTransition = TransitionInflater
                .from(MainActivity.this)
                .inflateTransition(R.transition.change_image_transform);

        Transition explodeTransition = TransitionInflater
                .from(MainActivity.this)
                .inflateTransition(android.R.transition.explode);

        /* Set the exit and return on the source fragment (ListMovieFragment) */
        listMovieFragment.setSharedElementReturnTransition(changeTransition);
        listMovieFragment.setExitTransition(explodeTransition);

        /* Set the enter on the destination fragment (MovieDetailFragment) */
        detailMovieFragment.setSharedElementEnterTransition(changeTransition);
        detailMovieFragment.setEnterTransition(explodeTransition);

        /* Get the shared imageview from the source fragment (MovieListFragment) */
        final ImageView ivSharedImage = (ImageView)findViewById(R.id.ivMoviePoster);

        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.activity_main, detailMovieFragment, "detailmoviefragment");
        fragmentTransaction.addToBackStack("detailmoviefragment");
        fragmentTransaction.addSharedElement(ivSharedImage, getResources().getString(R.string.transition_poster_image));
        fragmentTransaction.commit();
    } else {
        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.activity_main, new DetailMovieFragment(), "detailmoviefragment");
        fragmentTransaction.addToBackStack("detailmoviefragment");
        fragmentTransaction.commit();
    }
}

现在应该可以了。

P.S. 我已经使用并运行了您的代码，发现您有一些奇怪的转换，所以如果您遇到一些问题，请查看此 great article , 如何使用 fragment 进行平滑且用户友好的转换:)