java - 如何使 recyclerview 根据百分比仅显示一个数组？

Question

我希望 recyclerview 仅显示一个数组，但在数组列表中包含更多数组。必须显示的内容并不总是相同，而是取决于某些百分比。

例如:第一个数组有 20% 的机会，第二个有 50%，第三个也有 50%。并且会随机显示一个。但是当我刷新屏幕时它会改变。

我想我应该做的是为数组列表上的每个数组设置百分比，但我不知道该怎么做以及下一步要做什么。

这是我的 java 文件。

public class Comida extends AppCompatActivity implements Adaptador2.OnRecipeListener {
    private RecyclerView recyclerView1;
    List<Entidad2> listItems;
    Adaptador2 adaptor;
    private Entidad2 entidad1,entidad2,entidad3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_comida);

        recyclerView1 = findViewById(R.id.lv_1);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);

        recyclerView1.setLayoutManager(layoutManager);

        listItems = new ArrayList<>();
        entidad1 = new Entidad2(R.drawable.calabacines_3, "Solomillo a la plancha", " 10 min.", 4, 20);
        entidad2 = new Entidad2(R.drawable.patatas_deluxe_especiadas_70523_300_150, "Entrecot", " 15 min.", 2, 50);
        entidad3 = new Entidad2(R.drawable.tomate, "Hamburguesa", " 2 min.", 5, 100);


        listItems.add(entidad1);
        listItems.add(entidad2);
        listItems.add(entidad3);

        adaptor = new Adaptador2(listItems, this);
        recyclerView1.setAdapter(adaptor);
        adaptor.notifyDataSetChanged();
        pickEntidad();
    }
    @Override
    public void OnRecipe(int priority) {

        if (priority == 20) {
            Intent in = new Intent(this, Solomillo.class);
            startActivity(in);
        }
        if (priority == 50) {
            Intent in = new Intent(this, Entrecot.class);
            startActivity(in);
        }
        if (priority == 100) {
            Intent in = new Intent(this, Hamburguesa.class);
            startActivity(in);
        }
    }

    private void pickEntidad(){
        final int random = new Random().nextInt(101);

        int priority1 = entidad1.getPriority();
        int priority2 = entidad2.getPriority();
        int priority3 = entidad3.getPriority();


        listItems.clear();
        if(random < priority1){

            listItems.add(entidad1);

        }else if(random < priority2){

            listItems.add(entidad2);

        }else if (random <= priority3){

            listItems.add(entidad3);

        }
        adaptor.notifyDataSetChanged();
    }
}

这就是适配器:

public class Adaptador  extends RecyclerView.Adapter<Adaptador.ViewHolder> //implements View.OnClickListener
{
    private List<Entidad> listItems;
    private OnRecipeListener mOnRecipeListener;

    public  Adaptador(List<Entidad> listItems, OnRecipeListener onRecipeListener) {
        this.listItems = listItems;
        this.mOnRecipeListener = onRecipeListener;
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.elemento_lista, parent, false);
        //view.setOnClickListener(this);
        return new ViewHolder(view, mOnRecipeListener);
    }

    @Override
    public void onBindViewHolder(ViewHolder viewholder, int position) {
        int resource = listItems.get(position).getImgFoto();
        String title = listItems.get(position).getTitulo();
        String time = listItems.get(position).getTiempo();
        int barra = listItems.get(position).getRating();
        int fondo = listItems.get(position).getColorfondo();
        viewholder.setData(resource, title, time, barra, fondo);
    }

    @Override
    public int getItemCount() {
        return listItems.size();
    }
    class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        private ImageView imgFoto;
        private TextView titulo;
        private TextView tiempo;
        private RatingBar ratingBar;
        private ImageView colorfondo;
        OnRecipeListener onRecipeListener;

        public ViewHolder(View itemView, OnRecipeListener onRecipeListener) {
            super(itemView);

            imgFoto = itemView.findViewById(R.id.imgFoto);
            titulo = itemView.findViewById(R.id.tvTitulo);
            tiempo = itemView.findViewById(R.id.tvTiempo);
            ratingBar = itemView.findViewById(R.id.ratingBarVerd);
            colorfondo = itemView.findViewById(R.id.colorfondo);
            this.onRecipeListener = onRecipeListener;

            itemView.setOnClickListener(this);
        }

        private void setData(int resource, String title, String time, int barra, int fondo){
            imgFoto.setImageResource(resource);
            titulo.setText(title);
            tiempo.setText(time);
            ratingBar.setRating(barra);
            colorfondo.setImageResource(fondo);

        }

    @Override
    public void onClick(View v) {
        onRecipeListener.OnRecipe(getAdapterPosition());
    }
}

    public interface OnRecipeListener{
        void OnRecipe(int position);
    }
}

这是 Entidad 文件:

public class Entidad2 {

    private int imgFoto;
    private String titulo;
    private String tiempo;
    private int ratingBar;
    private int colorfondo;

    public Entidad2(int imgFoto, String titulo, String tiempo, int ratingBar, int colorfondo) {

        this.imgFoto = imgFoto;
        this.titulo = titulo;
        this.tiempo = tiempo;
        this.ratingBar = ratingBar;
        this.colorfondo = colorfondo;
    }

    public int getImgFoto() {
        return imgFoto;
    }

    public String getTitulo() {
        return titulo;
    }

    public String getTiempo() {
        return tiempo;
    }

    public int getRating() { return ratingBar; }

    public int getColorfondo() {
        return colorfondo;
    }
}

如果有人知道如何做，请告诉我。如果您需要更多代码，请告诉我，

谢谢。

enter image description here

这里@Emir 看看它是否在里面

public class Comida extends AppCompatActivity implements Adaptador2.OnRecipeListener {
    private RecyclerView recyclerView1;
    List<Entidad2> listItems;
    private Entidad2 entidad1,entidad2,entidad3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_comida);

        recyclerView1 = findViewById(R.id.lv_1);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);

        recyclerView1.setLayoutManager(layoutManager);

        listItems = new ArrayList<>();
        entidad1 = new Entidad2(R.drawable.calabacines_3, "Solomillo a la plancha", " 10 min.", 4, R.drawable.color_carnes, 50));
        entidad2 = new Entidad2(R.drawable.patatas_deluxe_especiadas_70523_300_150, "Entrecot", " 15 min.", 2, R.drawable.color_carnes, 200));
        entidad3 = new Entidad2(R.drawable.tomate, "Hamburguesa", " 2 min.", 5, R.drawable.color_carnes, 350));


        listItems.add(entidad1);
        listItems.add(entidad2);
        listItems.add(entidad3);

        Adaptador2 Adaptador2 = new Adaptador2(listItems, this);
        recyclerView1.setAdapter(Adaptador2);
        Adaptador2.notifyDataSetChanged();
        pickEntidad();
    }
    @Override
    public void OnRecipe(int position) {

        if (position == 0) {
            Intent in = new Intent(this, Solomillo.class);
            startActivity(in);
        }
    }

    private void pickEntidad(){
        final int random = new Random().nextInt(351);

        int priority1 = entidad1.getPriority();
        int priority2 = entidad2.getPriority();
        int priority3 = entidad3.getPriority();


        listItems.clear();
        if(random < priority1){

            listItems.add(entidad1);

        }else if(random < priority2){

            listItems.add(entidad2);

        }else if (random <= priority3){

            listItems.add(entidad3);

        }
        Adaptador2.notifyDataSetChanged();
    }
}

Answer 1

我的理解是，您想要以不同的显示机会随机显示 Entidad 列表中的单个 Entidad 对象。

例如:在 Entidad 对象上创建一个名为 Priority 的整数字段。将第一个 Entidad 的优先级设置为 50，第二个 200，第三个 350。创建以下方法以根据优先级随机选择。(创建 Entidad 对象后，将其引用保存在主 Activity 中。)

编辑:Entidad.java

public class Entidad {

private int imgFoto;
private String titulo;
private String tiempo;
private int ratingBar;
private int colorfondo;
private int priority;

public Entidad(int imgFoto, String titulo, String tiempo, int ratingBar, int colorfondo, int priority) {
    this.imgFoto = imgFoto;
    this.titulo = titulo;
    this.tiempo = tiempo;
    this.ratingBar = ratingBar;
    this.colorfondo = colorfondo;
    this.priority = priority;
}

public int getRatingBar() {
    return ratingBar;
}

public int getPriority() {
    return priority;
}

public int getImgFoto() {
    return imgFoto;
}

public String getTitulo() {
    return titulo;
}

public String getTiempo() {
    return tiempo;
}

public int getRating() { return ratingBar; }

public int getColorfondo() {
    return colorfondo;
}
}

编辑2:getEntidad()的使用

public class Comida extends AppCompatActivity implements Adaptador.OnRecipeListener {
private RecyclerView recyclerView1;
List<Entidad> listItems;
Adaptador adaptor;
private Entidad entidad1,entidad2,entidad3;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_comida);

    recyclerView1 = findViewById(R.id.lv_1);
    LinearLayoutManager layoutManager = new 
    LinearLayoutManager(this);
    layoutManager.setOrientation(LinearLayoutManager.VERTICAL);

    recyclerView1.setLayoutManager(layoutManager);

    listItems = new ArrayList<>();
//Initialize entidad objects and keep references of them to use in pickEntidad() method

   entidad1 = new Entidad(R.drawable.calabacines_3, "Solomillo a la plancha", " 10 min.", 4, R.drawable.color_carnes,50);
   entidad2 = new Entidad(R.drawable.patatas_deluxe_especiadas_70523_300_150, "Entrecot", " 15 min.", 2, R.drawable.color_carnes,200);
    entidad3 = new Entidad(R.drawable.tomate, "Hamburguesa", " 2 min.", 5, R.drawable.color_carnes,350);

    listItems.add(entidad1);
    listItems.add(entidad2); 
    listItems.add(entidad3);

    adaptor = new Adaptador(listItems, this);
    recyclerView1.setAdapter(adaptador);
    adaptor.notifyDataSetChanged();
//Call pickEntidad() to randomly pick one entidad and show on the list
    pickEntidad();
}

@Override
public void OnRecipe(int position) {

    if (position == 0) {
        Intent in = new Intent(this, Solomillo.class);
        startActivity(in);
    }
}
private void pickEntidad(){
//Generates random int value between 0-350
final int random = new Random().nextInt(351);

//get priorities from your created Entidad objects.
int priority1 = entidad1.getPriority();
int priority2 = entidad2.getPriority();
int priority3 = entidad3.getPriority();


listItems.clear()

//Pick one randomly depending on priority
if(random < priority1){

listItems.add(entidad1)

}else if(random < priority2){

listItems.add(entidad2)

}else if (random <= priority3){

listItems.add(entidad3)

}

//update your adapter

adaptor.notifyDataSetChanged()
}
}

每次您想要刷新列表时，请调用此 pickEntidad() 方法。不过，这是一种硬编码方法，如果您有太多项目并且不知道优先级值或范围，则该方法将毫无用处。您还可以通过生成 0-351 之间的整数来随机设置项目优先级。希望我正确理解你的问题。

另外，不要给变量名使用大写的后者。将“适配器”变量更改为“适配器”