android linearlayout类中java接口的实现

wi3ka0sx  于 2021-06-30  发布在  Java
关注(0)|答案(4)|浏览(284)

我有一个通用的 RecycleView 我有不同的行类，在这个行类中我想实现一个接口，我的目标是传递 OnQueryTextListener 到实现接口的活动或片段。

public class PlantDocHeader extends LinearLayout implements RecycleViewGenericAdapter.RecyclerViewRowHeader<PlantDocViewModel> {

    private Button buttonQuestion;
    private Button buttonPosts;
    private TextView searchTxtField;
    private ImageView imageViewExpandSearch;
    private SearchView searchView;
    private boolean expand = true;

    SearchView.OnQueryTextListener onQueryTextListener;
    private onTextChange onTextChange;

    Resources res;

    public PlantDocHeader(Context context) {
        super(context);
    }

    public PlantDocHeader(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public PlantDocHeader(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        searchTxtField = findViewById(R.id.textView_plant_doc_header_search);
        imageViewExpandSearch = findViewById(R.id.imageView_plant_doc_header_expand_button);
        searchView = findViewById(R.id.searchView_plant_doc_header);
        buttonQuestion = findViewById(R.id.button_plant_doc_header_filter_my_posts);
        buttonPosts = findViewById(R.id.button_plant_doc_header_filter_question);
    }

    @Override
    public void showData(PlantDocViewModel item) {
        res = getResources();

        buttonQuestion.setText(res.getString(R.string.question));
        buttonQuestion.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                AskQuestionFragment askQuestionFragment = new AskQuestionFragment();
                ChangeFragment(askQuestionFragment, (Activity) getContext(), false);
            }
        });

        buttonPosts.setText(res.getString(R.string.my_posts));
        buttonPosts.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                PlantDocMyPostsFragment myPostsFragment = new PlantDocMyPostsFragment();
                ChangeFragment(myPostsFragment, (Activity) getContext(), false);
            }
        });

        searchTxtField.setText(res.getString(R.string.search));
        imageViewExpandSearch.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if(expand){
                    searchView.setVisibility(VISIBLE);
                    imageViewExpandSearch.setImageResource(R.drawable.collapse);
                    expand = false;
                }else{
                    searchView.setVisibility(GONE);
                    imageViewExpandSearch.setImageResource(R.drawable.expand);
                    expand = true;
                }
            }
        });

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                Toast.makeText(getContext(), ""+newText, Toast.LENGTH_SHORT).show();
                onTextChange.textSearch(newText);
                return true;
            }
        });
    }

    public interface onTextChange {
        void textSearch(String searchText);
    }

}

这就是我犯的错误
尝试对空对象引用调用接口方法“void com.gardify.android.ui.plantdoc.plantdocheader$ontextchange.textsearch（java.lang.string）”
再循环通用适配器

/**
 * @param <T> is generic parameter type provided to List, OnRecyclerViewItemClickListener and RecyclerViewRow
 * @param <V> generic type for header view Model
 * @param <E> generic type for footer view Model
 */
public class RecycleViewGenericAdapter<T, V, E> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private List<T> mDataset;
    private V mHeaderData;
    private E mFooterData;

    private static final int TYPE_HEADER = 000;
    private static final int TYPE_ITEM = 111;
    private static final int TYPE_FOOTER = 222;

    private OnItemClickListener<T> onItemClickListener;
    private OnItemClickListenerHeader<V> onItemClickListenerHeader;
    private OnItemClickListenerFooter<E> onItemClickListenerFooter;

    private int layoutId, layoutIdHeader, layoutIdFooter;

    public RecycleViewGenericAdapter(List<T> mDataset, int layoutId, V mHeaderData, int layoutIdHeader,
                                     E mFooterData, int layoutIdFooter, OnItemClickListener<T> onItemClickListener,
                                     OnItemClickListenerHeader onItemClickListenerHeader, OnItemClickListenerFooter onItemClickListenerFooter) {
        this.onItemClickListener = onItemClickListener;
        this.onItemClickListenerHeader = onItemClickListenerHeader;
        this.onItemClickListenerFooter = onItemClickListenerFooter;
        this.mDataset = mDataset;
        this.mHeaderData = mHeaderData;
        this.mFooterData = mFooterData;
        this.layoutId = layoutId;
        this.layoutIdHeader = layoutIdHeader;
        this.layoutIdFooter = layoutIdFooter;

    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        RecyclerView.ViewHolder vh = null;
        if (viewType == TYPE_ITEM) {
            RecyclerViewRow<T> row = (RecyclerViewRow<T>) LayoutInflater.from(parent.getContext()).inflate(layoutId, parent, false);
            vh = new ItemViewHolder(row);
        }else if (viewType == TYPE_HEADER) {
            RecyclerViewRowHeader<V> rowHeader = (RecyclerViewRowHeader<V>) LayoutInflater.from(parent.getContext()).inflate(layoutIdHeader, parent, false);
            vh = new HeaderViewHolder(rowHeader);
        } else if(viewType == TYPE_FOOTER) {
            RecyclerViewRowFooter<E> footerRow = (RecyclerViewRowFooter<E>) LayoutInflater.from(parent.getContext()).inflate(layoutIdFooter, parent, false);
            vh = new FooterViewHolder(footerRow);
        }
        return vh;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, final int position) {
        if (holder instanceof RecycleViewGenericAdapter.ItemViewHolder) {
            ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
            itemViewHolder.onBind((mHeaderData!=null? position-1 : position), itemViewHolder);
        } else if (holder instanceof RecycleViewGenericAdapter.HeaderViewHolder) {
            HeaderViewHolder headerViewHolder = (HeaderViewHolder) holder;
            headerViewHolder.onBind(headerViewHolder);
        } else if (holder instanceof RecycleViewGenericAdapter.FooterViewHolder) {
            FooterViewHolder footerViewHolder = (FooterViewHolder) holder;
            footerViewHolder.onBind(footerViewHolder);
        }
    }

    @Override
    public int getItemCount() {
        if (mHeaderData != null && mFooterData != null) {
            return mDataset.size() + 2;
        } else if (mHeaderData != null || mFooterData != null) {
            return mDataset.size() + 1;
        }
        return mDataset.size();
    }

    private int getLastPosition() {
        return getItemCount() - 1;
    }

    private boolean isLastPosition(int position) {
        return position == getLastPosition();
    }

    @Override
    public int getItemViewType(int position) {
        if (position == 0 && mHeaderData!=null) {
            return TYPE_HEADER;
        } else if (isLastPosition(position) && mFooterData!=null) {
            return TYPE_FOOTER;
        } else {
            return TYPE_ITEM;
        }
    }

    /**
     * Item ViewHolder
   **/
    public class ItemViewHolder extends RecyclerView.ViewHolder {
        public RecyclerViewRow<T> mRow;

        public ItemViewHolder(RecyclerViewRow<T> itemView) {
            super((View) itemView);
            mRow = itemView;
        }

        private void onBind(final int position, ItemViewHolder viewHolder) {

            viewHolder.mRow.showData(mDataset.get(position));
            ((View) viewHolder.mRow).setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (onItemClickListener != null) {
                        onItemClickListener.onItemClick(mDataset.get(position));
                    }
                }
            });
        }
    }

    public interface RecyclerViewRow<T> {
        void showData(T item);
    }

    public interface OnItemClickListener<T> {
        void onItemClick(T position);
    }

    public void updateList(List<T> _mDataset){
        this.mDataset= _mDataset;
        notifyDataSetChanged();
    }

    /**
     * Header ViewHolder
   **/
    public class HeaderViewHolder extends RecyclerView.ViewHolder {
        public RecyclerViewRowHeader<V> mRowHeader;

        public HeaderViewHolder(RecyclerViewRowHeader<V> itemView) {
            super((View) itemView);
            mRowHeader = itemView;
        }

        private void onBind(HeaderViewHolder viewHolder) {
            viewHolder.mRowHeader.showData(mHeaderData);
            ((View) viewHolder.mRowHeader).setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (onItemClickListenerHeader != null) {
                        onItemClickListenerHeader.onItemClickHeader(mHeaderData);
                    }
                }
            });
        }
    }

    public interface RecyclerViewRowHeader<V> {
        void showData(V item);
    }

    public interface OnItemClickListenerHeader<V> {
        void onItemClickHeader(V position);
    }

    /**
     * Footer ViewHolder
   **/
    public class FooterViewHolder extends RecyclerView.ViewHolder {
        public RecyclerViewRowFooter<E> mRowFooter;

        public FooterViewHolder(RecyclerViewRowFooter<E> itemView) {
            super((View) itemView);
            mRowFooter = itemView;
        }

        private void onBind(FooterViewHolder viewHolder) {
            viewHolder.mRowFooter.showData(mFooterData);
            ((View) viewHolder.mRowFooter).setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (onItemClickListenerFooter != null) {
                        onItemClickListenerFooter.onItemClickFooter(mFooterData);
                    }
                }
            });
        }
    }

    public interface RecyclerViewRowFooter<E> {
        void showData(E item);
    }

    public interface OnItemClickListenerFooter<E> {
        void onItemClickFooter(E position);
    }
}

片段中的用法

public class PlantDocFragment extends Fragment implements RecycleViewGenericAdapter.OnItemClickListener<PlantDocViewModel>, PlantDocHeader.OnTextChangeListener {

//...

    RecycleViewGenericAdapter<PlantDocViewModel, PlantDocViewModel, Nullable> adapter = new RecycleViewGenericAdapter<>(plantDocList, R.layout.recycler_view_plant_doc_row_item, plantDocHeader, R.layout.recycler_view_plant_doc_header,
                    null, 0, this, null, null);

//...

@Override
public void textSearch(String searchText) {
    Toast.makeText(getContext(), "searched text : "+searchText, Toast.LENGTH_SHORT).show();
}

我正在使用的通用回收视图可以在这里找到

JavaandroidInterface

4条答案

按热度按时间
rks48beu

rks48beu1#

你还没告诉我打电话时该怎么办 textSearch() 方法。
你必须实施 onTextChange 接口（在声明接口/类/变量时请遵循java命名约定）在某个类中，您将在其中重写 textSearch() 方法，然后将引用（实现的类）传递给变量 onTextChange （您已经为接口和示例变量指定了相同的名称，所以为了避免混淆，您可以为变量指定另一个名称）。当你打电话的时候 textSearch() 在这条线上 onTextChange.textSearch(newText); 你将有一个实现。你的代码也能用。

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68bkxrlz

68bkxrlz2#

首先，即使不是强制性的，您也应该始终遵循java命名约定，例如您的名字 interface 应该是这样的 OnTextChangeListener .
你的错误是因为你做了手术， onTextChange.textSearch(newText) 不为引用指定示例， onTextChange .
你可以这样做

public class PlantDocHeader extends LinearLayout implements RecycleViewGenericAdapter.RecyclerViewRowHeader<PlantDocViewModel> {

    //...

    private OnTextChangeListener onTextChange;

    //...

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                Toast.makeText(getContext(), ""+newText, Toast.LENGTH_SHORT).show();
                onTextChange = new OnTextChangeListener() {
                    public void textSearch(String searchText) {
                        //...
                    }                   
                };
                onTextChange.textSearch("Hello");// Replace "Hello" with the required parameter
                return true;
            }
        });
    }

    public interface OnTextChangeListener {
        void textSearch(String searchText);
    }
}
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huwehgph

huwehgph3#

在适配器中创建公共方法：

public void setOnTextChange(onTextChange onTextChange) {
        this.onTextChange = onTextChange;
    }

在你的片段中，改变你的 implements 要实现接口：

implements PlantDocHeader.OnTextChange

然后设置ContextChange：

adapter.setOnTextChange(this);
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hi3rlvi2

hi3rlvi24#

基本上，您需要将片段引用传递给 HeaderView .
首先，你得有个二传手 PlantDocHeader 如下所示。我把界面也去掉了，好像没用。

public class PlantDocHeader<T> extends LinearLayout {
    private OnTextChangeListener onTextChangeListener;
    public void setOnTextChangeListener(OnTextChangeListener onTextChangeListener) {
        this.onTextChangeListener = onTextChangeListener;
    }
    public void setData(T data) {

    }
}

对适配器构造函数重新措辞一点，它需要大量的参数构建器可能会有所帮助，或者您可以为可选属性创建单独的设置器。

public class RecycleViewGenericAdapter<T, V, E> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private OnItemClickListener<T> onItemClickListener;
    private OnItemClickListenerHeader<V> onItemClickListenerHeader;
    private OnItemClickListenerFooter<E> onItemClickListenerFooter;
    private PlantDocHeader.OnTextChangeListener onTextChangeListener;
    private int layoutId, layoutIdHeader, layoutIdFooter;

    public RecycleViewGenericAdapter(List<T> mDataset, int layoutId, V mHeaderData, int layoutIdHeader,
                                     E mFooterData, int layoutIdFooter) {
        this.mDataset = mDataset;
        this.mHeaderData = mHeaderData;
        this.mFooterData = mFooterData;
        this.layoutId = layoutId;
        this.layoutIdHeader = layoutIdHeader;
        this.layoutIdFooter = layoutIdFooter;
    }
}

为所有侦听器创建单独的setter，并根据调用组件的需要进行设置。现在，当你完成设置你需要通过 onTextChangeListener 到页眉视图。

public class HeaderViewHolder extends RecyclerView.ViewHolder {
    public RecyclerViewRowHeader<V> mRowHeader;
    public HeaderViewHolder(RecyclerViewRowHeader<V> itemView) {
        super((View) itemView);
        mRowHeader = itemView;
    }
    private void onBind(HeaderViewHolder viewHolder) {
        viewHolder.mRowHeader.setOnTextChangeListener(onTextChangeListener);
        viewHolder.mRowHeader.showData(mHeaderData);
        ((View) viewHolder.mRowHeader).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (onItemClickListenerHeader != null) {
                    onItemClickListenerHeader.onItemClickHeader(mHeaderData);
                }
            }
        });
    }
}

现在应该可以了。另外，您可能需要考虑在侦听器之间传递位置，因为可以有多个头，如果没有，则始终为0。
如果你试图创建一个泛型适配器，你应该考虑现在就创建一个抽象适配器类，你的类看起来不是泛型的，因为你在构造函数中传递了太多的参数，而这些参数应该只在子类中传递，它一点也不灵活。您可能需要检查一些开放源码通用适配器来查看。

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