【Android TV 开发】--＞Leanback 中 VerticalGridSupportFragment 的使用

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具体使用

0. 清单文件中添加

1. 添加依赖

implementation 'androidx.leanback:leanback:1.0.0'
implementation 'androidx.leanback:leanback-preference:1.0.0'

2. 布局文件 activity_test.xml

3. VerticalGridFragment.java

public class VerticalGridFragment extends VerticalGridSupportFragment {
    private static final int COLUMNS = 4;
    private static final int ZOOM_FACTOR = FocusHighlight.ZOOM_FACTOR_MEDIUM;
    private ArrayObjectAdapter mAdapter;

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

        setTitle(getString(R.string.browse_title));

        setupRowAdapter();
    }

    private void setupRowAdapter() {
        VerticalGridPresenter gridPresenter = new VerticalGridPresenter(ZOOM_FACTOR);
        gridPresenter.setNumberOfColumns(COLUMNS);
        setGridPresenter(gridPresenter);

        PresenterSelector cardPresenterSelector = new CardPresenterSelector(getActivity());
        mAdapter = new ArrayObjectAdapter(cardPresenterSelector);
        setAdapter(mAdapter);

        prepareEntranceTransition();
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                createRows();
                startEntranceTransition();
            }
        }, 1000);
    }

    private void createRows() {
        String json = Utils.inputStreamToString(getResources()
                .openRawResource(R.raw.grid_example));
        CardRow row = new Gson().fromJson(json, CardRow.class);
        mAdapter.addAll(0, row.getCards());
    }
}

4. CardPresenterSelector.java

public class CardPresenterSelector extends PresenterSelector {
    private final Context mContext;
    private final HashMap presenters = new HashMap();

    public CardPresenterSelector(Context context) {
        mContext = context;
    }

    @Override
    public Presenter getPresenter(Object item) {
        if (!(item instanceof Card)) throw new RuntimeException(
                String.format("The PresenterSelector only supports data items of type '%s'",
                        Card.class.getName()));
        Card card = (Card) item;
        Presenter presenter = presenters.get(card.getType());
        if (presenter == null) {
            switch (card.getType()) {
                case SINGLE_LINE:
//                    presenter = new SingleLineCardPresenter(mContext);
                    break;
                case VIDEO_GRID:
//                    presenter = new VideoCardViewPresenter(mContext, R.style.VideoGridCardTheme);
                    break;
                case MOVIE:
                case MOVIE_BASE:
                case MOVIE_COMPLETE:
                case SQUARE_BIG:
                case GRID_SQUARE:
                case GAME: {
                    int themeResId = R.style.MovieCardSimpleTheme;
                    if (card.getType() == Card.Type.MOVIE_BASE) {
                        themeResId = R.style.MovieCardBasicTheme;
                    } else if (card.getType() == Card.Type.MOVIE_COMPLETE) {
                        themeResId = R.style.MovieCardCompleteTheme;
                    } else if (card.getType() == Card.Type.SQUARE_BIG) {
                        themeResId = R.style.SquareBigCardTheme;
                    } else if (card.getType() == Card.Type.GRID_SQUARE) {
                        themeResId = R.style.GridCardTheme;
                    } else if (card.getType() == Card.Type.GAME) {
                        themeResId = R.style.GameCardTheme;
                    }
                    presenter = new ImageCardViewPresenter(mContext, themeResId);
                    break;
                }
                case SIDE_INFO:
                    presenter = new SideInfoCardPresenter(mContext);
                    break;
                case TEXT:
//                    presenter = new TextCardPresenter(mContext);
                    break;
                case ICON:
//                    presenter = new IconCardPresenter(mContext);
                    break;
                case CHARACTER:
//                    presenter = new CharacterCardPresenter(mContext);
                    break;
                default:
                    presenter = new ImageCardViewPresenter(mContext);
                    break;
            }
        }
        presenters.put(card.getType(), presenter);
        return presenter;
    }
}

6. 资源文件 raw/grid_example.json

{
  "cards": [
    {
      "type": "GRID_SQUARE",
      "title": "Nüsse",
      "description": "$3.99/lb",
      "localImageResource": "food_01"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Undefinierbar",
      "description": "$3.99/lb",
      "localImageResource": "food_02"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Brocoli",
      "description": "$3.99/lb",
      "localImageResource": "food_03"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Salat",
      "description": "$3.99/lb",
      "localImageResource": "food_04"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Große Radischen",
      "description": "$3.99/lb",
      "localImageResource": "food_05"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Rote Zwiebeln",
      "description": "$3.99/lb",
      "localImageResource": "food_06"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Lauch",
      "description": "$3.99/lb",
      "localImageResource": "food_07"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Exotisches Zeugs",
      "description": "$3.99/lb",
      "localImageResource": "food_08"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Zitronen",
      "description": "$3.99/lb",
      "localImageResource": "food_09"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Meerirgendwas",
      "description": "$3.99/lb",
      "localImageResource": "food_10"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Irgendein Kohl",
      "description": "$3.99/lb",
      "localImageResource": "food_11"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Apfel",
      "description": "$3.99/lb",
      "localImageResource": "food_12"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Mehr Äpfel",
      "description": "$3.99/lb",
      "localImageResource": "food_13"
    },
    {
      "type": "GRID_SQUARE",
      "title": "Tomaten",
      "description": "$3.99/lb",
      "localImageResource": "food_14"
    }
  ]
}