习题模块知识点整理

一、ListView

• 习题页面显示章节习题
• 习题详情页面显示习题的题目及选项，选择选项后判断选项是否正确

 public void onBindViewHolder(@NonNull final ExerciseDetailAdapter.ViewHolder holder, final int position) {
        //1.获取数据
        ExerciseDetail detail = details.get(position);
        //2.给控件赋值
        holder.subject.setText(detail.getSubject());
        holder.tvA.setText(detail.getA());
        holder.tvB.setText(detail.getB());
        holder.tvC.setText(detail.getC());
        holder.tvD.setText(detail.getD());

        holder.ivA.setImageResource(R.drawable.ic_exercise_a);
        holder.ivB.setImageResource(R.drawable.ic_exercise_b);
        holder.ivC.setImageResource(R.drawable.ic_exercise_c);
        holder.ivD.setImageResource(R.drawable.ic_exercise_d);

        //3.设置监听，并处理事件（根据选项判断答案是否正确，显示相应的图标）
        holder.ivA.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String pos=String.valueOf(position);
                if (selectedPods.contains(pos)){
                    selectedPods.remove(pos);
                } else {
                    selectedPods.add(pos);
                }
                onSelectListener.onSelectA(position,holder.ivA,holder.ivB,holder.ivC,holder.ivD);
            }
        });
        holder.ivB.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                String pos=String.valueOf(position);
                if (selectedPods.contains(pos)){
                    selectedPods.remove(pos);
                } else {
                    selectedPods.add(pos);
                }
                onSelectListener.onSelectB(position,holder.ivA,holder.ivB,holder.ivC,holder.ivD);
            }
        });
        holder.ivC.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                String pos=String.valueOf(position);
                if (selectedPods.contains(pos)){
                    selectedPods.remove(pos);
                } else {
                    selectedPods.add(pos);
                }
                onSelectListener.onSelectC(position,holder.ivA,holder.ivB,holder.ivC,holder.ivD);
            }
        });
        holder.ivD.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                String pos=String.valueOf(position);
                if (selectedPods.contains(pos)){
                    selectedPods.remove(pos);
                } else {
                    selectedPods.add(pos);
                }
                onSelectListener.onSelectD(position,holder.ivA,holder.ivB,holder.ivC,holder.ivD);
            }
        });
    }

二、Adapter和AdapterView

• 根据记录数，加载每个view

   @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        //1.加载xml布局，只需要加载一次
        if(convertView ==null){
            holder=new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(R.layout.item_exercise,null);
            //2.获取控件
            holder.tvtvOder=convertView.findViewById(R.id.tv_order);
            holder.tvTitle=convertView.findViewById(R.id.tv_title);
            holder.tvSubTitle=convertView.findViewById(R.id.tv_sub_title);
            convertView.setTag(holder);
        }else{
            holder=(ViewHolder)convertView.getTag();
        }


        //3.加载数据
        final  Exercise exercise=getItem(position);
        if(exercise!=null){
            holder.tvtvOder.setText(String.valueOf(position+1));
            holder.tvtvOder.setBackgroundResource(R.drawable.circle);
            holder.tvTitle.setText(exercise.getTitle());
            holder.tvSubTitle.setText(exercise.getSubTitle());
            convertView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {

                }
            });
        }
        return convertView;
    }

三、适配器

• 初始化控件、获取控件、设置布局

 public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // 1. 初始化数据
        initData();
        // 2. 获取控件
        View view = inflater.inflate(R.layout.fragment_recycler_view, container, false);
        RecyclerView recyclerView = view.findViewById(R.id.recycle_view);
        // 3. 设置布局和分割线
        LinearLayoutManager manager = new LinearLayoutManager(container.getContext());
        manager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(manager);
        recyclerView.addItemDecoration(new DividerItemDecoration(container.getContext(),
                DividerItemDecoration.VERTICAL));
        // 4. 创建适配器
        RecyclerViewAdapter adapter = new RecyclerViewAdapter(exercises);
        // 5. 设置适配器
        recyclerView.setAdapter(adapter);

        // 6. 设置监听器
        adapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Exercise exercise = exercises.get(position);
                //跳转到相应的章节习题
                Intent intent = new Intent(getContext(), ExerciseDetailActivity.class);
                intent.putExtra("id", exercise.getId());//用于识别是哪个xml文件
                intent.putExtra("title", exercise.getTitle());//用于设置详情的标题栏
                getContext().startActivity(intent);
            }

            @Override
            public void onItemLongClick(View view, int position) {

            }
        });
        return view;
    }

四、RecyclerView控件

• 为RecyclerView准备一个适配器，新建RecyclerViewAdapter类，让适配器继承自RecyclerView.Adapter，并将泛型指定RecyclerViewAdapter.ViewHolder。
  代码如下：

public class RecyclerViewAdapter<V extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
    private List<Exercise> exercises;

    static class ViewHolder extends RecyclerView.ViewHolder{
        TextView tvtvOder,tvTitle,tvSubTitle;

        public ViewHolder(View view){
            super(view);
            tvtvOder= view.findViewById(R.id.tv_order);
            tvTitle= view.findViewById(R.id.tv_title);
            tvSubTitle= view.findViewById(R.id.tv_sub_title);
        }
    }
    public RecyclerViewAdapter(List<Exercise> exerList){
        exercises=exerList;
    }
    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_exercise , parent ,false);
        ViewHolder holder = new ViewHolder(view);
        //设置Item点击的监听器
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
        Exercise exercise= exercises.get(position);
        holder.tvTitle.setText(exercise.getTitle());
        holder.tvtvOder.setText(String.valueOf(position+1));
        holder.tvSubTitle.setText(exercise.getSubTitle());
//        //设置圆角背景的颜色
//        GradientDrawable drawable=(GradientDrawable) holder.tvtvOder.getBackground();
//        drawable.setColor(Color.parseColor(exercise.getBgColor()));
        //设置监听
        if(itemClickLisrener != null){
            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    itemClickLisrener.onItemClick(holder.itemView,position);
                }
            });
            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    itemClickLisrener.onItemLongClick(holder.itemView,position);
                    return true;
                }
            });
        }


    }
    private OnItemClickLisrener itemClickLisrener;
    public void setOnItemClickListener(OnItemClickLisrener listener){
        this.itemClickLisrener=listener;
    }
    //回调事件的接口
    public interface  OnItemClickLisrener{
        void onItemClick(View view,int position);
        void onItemLongClick(View view,int positon);
    }
    @Override
    public int getItemCount() {
        return exercises.size();
    }

}

五、运行效果图

习题页面.png
习题详情页面.png