java - 无法在其Adapter中调用Fragment的功能，Android应用程序开发

Question

我正在制作一个Android应用程序，当单击图像时，它会模糊并在其顶部显示播放和其他选项。我正在使用外部库( https://github.com/daimajia/AndroidViewHover )来实现这种特殊效果，但我的问题本质上是通用的。

问题陈述:-

我正在处理模糊表面显示的播放选项上的点击事件，即适配器中的hover_sample.xml (TrendingAdapter.java)，并且我想调用用于播放 youtube 视频的函数 ( public void openWebView(TrendingData image)) 位于 fragment (TrendingFragment.java) 中。所以，本质上我想从其适配器访问 fragment 中的函数。

我尝试过各种方法，但都不起作用。代码示例如下。

TrendingFragment.java:-

    public class TrendingFragment extends Fragment implements AdapterView.OnItemClickListener, AdapterCallback {

            private GridView mGridView;
            private TrendingAdapter mAdapter;
            private String movieJson;
            private String caption;


            Activity MyActivity = getActivity();


            public static TrendingFragment getInstance() {
                TrendingFragment fragment = new TrendingFragment();

                return fragment;
            }

            @Override
            public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
                return inflater.inflate( R.layout.activity_trending_fragment, container, false );
            }

            @Override
            public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
                super.onViewCreated(view, savedInstanceState);

                mGridView = (GridView) view.findViewById( R.id.grid );
                mGridView.setOnItemClickListener( this );
                mGridView.setDrawSelectorOnTop( true );


                TrendingActivity activity = (TrendingActivity) getActivity();
                movieJson = activity.getMovieJson();
                caption   = activity.getNewCaption();
            }

            @Override
            public void onActivityCreated(@Nullable Bundle savedInstanceState) {
                super.onActivityCreated(savedInstanceState);

                mAdapter = new TrendingAdapter( getActivity(), 0, this);
                mGridView.setAdapter(mAdapter);

                RestAdapter restAdapter = new RestAdapter.Builder()
                        .setEndpoint(movieJson)
                        .build();

                TrendingApiInterface trendingApiInterface = restAdapter.create( TrendingApiInterface.class );

                trendingApiInterface.getStreams(new Callback<List<TrendingData>>() {
                    @Override
                    public void success(List<TrendingData> galleryImages, Response response) {
                        if (galleryImages == null || galleryImages.isEmpty() || !isAdded() )
                            return;


                        for (TrendingData image : galleryImages) {

                            mAdapter.add(image);
                        }

                        mAdapter.notifyDataSetChanged();
                    }

                    @Override
                    public void failure(RetrofitError error) {

                    }
                });
            }

            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TrendingData image = (TrendingData) parent.getItemAtPosition( position );

                openWebView(image);
            }



            public void openWebView(TrendingData image) {

                try {

                    Intent intent = YouTubeStandalonePlayer.createVideoIntent(getActivity(), Config.YOUTUBE_API_KEY, image.getImage());
                    startActivity(intent);
                }//If Youtube app is not present then open in webview
                catch (ActivityNotFoundException ex){

                    Toast.makeText(getActivity(), "Please wait for few minutes.Its Loading...", Toast.LENGTH_SHORT).show();

                    Toast.makeText(getActivity(), "Latest Youtube Player is missing on your device.Opening in WebView.Download it for better experience", Toast.LENGTH_LONG).show();
                    String complete_url="https://www.youtube.com/watch?v=";
                    Intent intent = new Intent(getActivity(), webView.class );
                    intent.putExtra( webView.EXTRA_IMAGE, complete_url+image.getImage());
                    intent.putExtra( webView.PREVIOUS_ACTIVITY, "TrendingActivity.class");
                    intent.putExtra(webView.EXTRA_CAPTION, image.getCaption());
                    intent.putExtra( webView.EXTRA_BG_IMAGE, image.getBgImage());
                    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    //finish();
                    startActivity(intent);

                }

            }

    @Override
    public void onMethodCallback(AdapterView<?> parent, View view, int position, long id) {

        TrendingData image = (TrendingData) parent.getItemAtPosition( position );

        openWebView(image);

    }
}

TrendingAdapter.java:-

公共(public)类 TrendingAdapter 扩展了 ArrayAdapter {

TrendingFragment lfg;
TrendingData image;
private AdapterCallback mAdapterCallback;

public TrendingAdapter(Context context, int resource, AdapterCallback callback) {
    super(context, resource);

    this.mAdapterCallback = callback;

}



//hover image

private BlurLayout mSampleLayout ;


@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
    final ViewHolder holder;

    if( convertView == null ) {
        holder = new ViewHolder();
        convertView = LayoutInflater.from( getContext() ).inflate( R.layout.activity_trending_adapter, parent, false );
        holder.image = (ImageView) convertView.findViewById( R.id.image );
        holder.caption=(TextView) convertView.findViewById(R.id.textView);
        //holder.progress = (ProgressBar) convertView.findViewById(R.id.progressBar);
        convertView.setTag(holder);

        BlurLayout.setGlobalDefaultDuration(450);
        mSampleLayout = (BlurLayout)convertView.findViewById(R.id.blur_layout);
        final View hover = LayoutInflater.from(getContext()).inflate(R.layout.hover_sample, null);

        holder.play = (ImageView)hover.findViewById(R.id.heart);
        holder.playList = (ImageView)hover.findViewById(R.id.share);

        hover.findViewById(R.id.heart).setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                YoYo.with(Techniques.Tada)
                                .duration(550)
                                .playOn(v);


            }
                });

        hover.findViewById(R.id.share).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                YoYo.with(Techniques.Swing)
                        .duration(550)
                        .playOn(v);

            }
        });

        mSampleLayout.setHoverView(hover);
        mSampleLayout.setBlurDuration(550);
        mSampleLayout.addChildAppearAnimator(hover, R.id.heart, Techniques.FlipInX, 550, 0);
        mSampleLayout.addChildAppearAnimator(hover, R.id.share, Techniques.FlipInX, 550, 250);
        mSampleLayout.addChildAppearAnimator(hover, R.id.more, Techniques.FlipInX, 550, 500);

        mSampleLayout.addChildDisappearAnimator(hover, R.id.heart, Techniques.FlipOutX, 550, 500);
        mSampleLayout.addChildDisappearAnimator(hover, R.id.share, Techniques.FlipOutX, 550, 250);
        mSampleLayout.addChildDisappearAnimator(hover, R.id.more, Techniques.FlipOutX, 550, 0);

        mSampleLayout.addChildAppearAnimator(hover, R.id.description, Techniques.FadeInUp);
        mSampleLayout.addChildDisappearAnimator(hover, R.id.description, Techniques.FadeOutDown);



    } else {
        holder = (ViewHolder) convertView.getTag();
    }


    final ViewHolder tmp = holder;


    Picasso.with(getContext()).load(getItem(position).getThumbnail())
            .placeholder(getContext().getResources().getDrawable(R.drawable.place)).
            error(getContext().getResources().getDrawable(R.drawable.place)).
            into(holder.image);

    return convertView;
}



private class ViewHolder {
    ImageView   image;
    ProgressBar progress;
    TextView    caption;
    ImageView   play;
    ImageView   playList;

}

}

hover_sample.xml:-

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout
        android:id="@+id/animation_area"
        android:layout_centerInParent="true"
        android:layout_width="match_parent"
        android:orientation="horizontal"
        android:gravity="center"
        android:layout_height="match_parent">
        <ImageView
            android:layout_marginRight="20dp"
            android:id="@+id/heart"
            android:src="@drawable/heart"
            android:layout_width="50dp"
            android:layout_height="50dp" />
        <ImageView
            android:id="@+id/share"
            android:layout_marginRight="20dp"
            android:src="@drawable/share"
            android:layout_width="50dp"
            android:layout_height="50dp"/>
        <ImageView
            android:id="@+id/more"
            android:src="@drawable/more"
            android:layout_width="50dp"
            android:layout_height="50dp"/>
    </LinearLayout>
    <TextView
        android:id="@+id/description"
        android:text="Parse PHP SDK"
        android:layout_marginLeft="12dp"
        android:textColor="#ffffff"
        android:layout_marginBottom="12dp"
        android:layout_alignParentBottom="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</RelativeLayout>

请建议如何实现同样的目标。对于类似的问题，我尝试了此表单中建议的各种方法，但没有成功。

Answer 1

使用回调方法。创建一个界面。让你的 fragment 实现它。将回调传递给适配器的构造函数。适配器使用回调来调用接口(interface)方法，您可以从中调用 webview()。

参见How to create interface between fragment and adapter 。

从 fragment 调用任何适配器的方法时，您可以使用适配器的实例，但从适配器到 fragment 的通信应通过回调完成。