java - 检索列表需要花费大量时间

Question

public class ProductsAll extends AppCompatActivity {

ListView prdctlist;
int count=0;
//Integer[] productimage={R.drawable.img1,R.drawable.img2,R.drawable.img3,R.drawable.img4,R.drawable.img5,R.drawable.img6,R.drawable.img7};
Integer[] productimage={R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher};
FirebaseFirestore ff;
CollectionReference cref;
DocumentReference dref;
ArrayList<Product> product;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_products_all);
    prdctlist=findViewById(R.id.productlist);
    product=new ArrayList<>();

    ff=FirebaseFirestore.getInstance();
    cref=ff.collection("Products");

    cref.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()) {
                for (DocumentSnapshot document : task.getResult()) {
                    String pdesc = document.getString("pdesc");
                    String pname = document.getString("pname");
                    String pprice = document.getString("pprice");
                    String pstock = document.getString("pstock");
                    Product p=new Product(productimage[count++],pname,pdesc,pprice,pstock);
                    product.add(p);
                    Log.d("MyTag", pdesc + " / " + pname + " / " + pprice + " / " + pstock);
                }
                MyProductAdapter ma = new MyProductAdapter(ProductsAll.this,product);
                prdctlist.setAdapter(ma);
            }
        }
    });
}

public class Product {
String pname,pdesc,pprice,pquant;
Integer pimage;

public Product(Integer pimage,String pname, String pdesc, String pprice, String pquant) {
    this.pname = pname;
    this.pimage=pimage;
    this.pdesc = pdesc;
    this.pprice = pprice;
    this.pquant = pquant;
}

public Integer getPimage() {
    return pimage;
}

public void setPimage(Integer pimage) {
    this.pimage = pimage;
}

public String getPname() {
    return pname;
}

public void setPname(String pname) {
    this.pname = pname;
}

public String getPdesc() {
    return pdesc;
}

public void setPdesc(String pdesc) {
    this.pdesc = pdesc;
}

public String getPprice() {
    return pprice;
}

public void setPprice(String pprice) {
    this.pprice = pprice;
}

public String getPquant() {
    return pquant;
}

public void setPquant(String pquant) {
    this.pquant = pquant;
}

public class MyProductAdapter extends BaseAdapter {

Integer pimage;
Context con;
ImageView prdctimg;

LayoutInflater prdctinflater;
View prdctview;
TextView prdctname,prdctdesc,prdctprice,prdctquant;
ArrayList<Product> product;

@Override
public int getCount() {
    return product.size();
}

@Override
public Object getItem(int i) {
    return product.get(i).getPname();
}

public MyProductAdapter(Context con,ArrayList<Product> product) {
    /*this.pimage = productimage;*/
    this.product=product;
    this.con = con;
    /*this.productname = productname;
    this.productdescription = productdescription;
    this.productquantity = productquantity;
    this.productprice = productprice;*/
    prdctinflater=LayoutInflater.from(con);
}

@Override
public long getItemId(int i) {
    return i;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    prdctview=prdctinflater.inflate(R.layout.plist,null);
    prdctname=prdctview.findViewById(R.id.pname);
    prdctdesc=prdctview.findViewById(R.id.pdesc);
    prdctimg=prdctview.findViewById(R.id.ppic);
    prdctprice=prdctview.findViewById(R.id.pprice);
    prdctquant=prdctview.findViewById(R.id.pquant);

    prdctimg.setImageResource(product.get(i).getPimage());
    prdctname.setText(product.get(i).getPname().toString());
    prdctdesc.setText(product.get(i).getPdesc().toString());
    prdctprice.setText(product.get(i).getPprice().toString());
    prdctquant.setText(product.get(i).getPquant().toString());
    return prdctview;
}

public void insertdb(EditText pname, String pdesc,String pprice,String pquant,int mode) //mode 1-insert 2-update 3-delete
{
    this.pName=pname;
    pd=pdesc;
    pq=pquant;
    pp=pprice;
    ff=FirebaseFirestore.getInstance();
    cref=ff.collection("Products");
    dref=cref.document(pname.getText().toString());
    if(mode==1)
    {
        dref.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                    DocumentSnapshot document = task.getResult();
                    if (document.exists()) {
                        pName.setError("Product Name already exists");
                    } else {
                        Map<String,Object> m=new HashMap<>();
                        m.put("pname",pName.getText().toString());
                        m.put("pdesc",pd);
                        m.put("pprice",pp);
                        m.put("pstock",pq);


                        dref.set(m).addOnSuccessListener(new OnSuccessListener<Void>() {
                            @Override
                            public void onSuccess(Void aVoid) {
                                aistatus.setVisibility(View.VISIBLE);
                                aistatus.setText("Inserted Product Details");
                                Toast.makeText(AdminHome.this, "Inserted Product Details", Toast.LENGTH_SHORT).show();
                            }
                        }).addOnFailureListener(new OnFailureListener() {
                            @Override
                            public void onFailure(@NonNull Exception e) {
                                aistatus.setVisibility(View.VISIBLE);
                                aistatus.setText("Couldn't insert Product details");
                            }
                        });
                    }
                } else {
                    Map<String,Object> m=new HashMap<>();
                    m.put("pname",pName.getText().toString());
                    m.put("pdesc",pd);
                    m.put("pprice",pp);
                    m.put("pstock",pq);


                    dref.set(m).addOnSuccessListener(new OnSuccessListener<Void>() {
                        @Override
                        public void onSuccess(Void aVoid) {
                            aistatus.setVisibility(View.VISIBLE);
                            aistatus.setText("Inserted Product Details");
                            Toast.makeText(AdminHome.this, "Inserted Product Details", Toast.LENGTH_SHORT).show();
                        }
                    }).addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            aistatus.setVisibility(View.VISIBLE);
                            aistatus.setText("Couldn't insert Product details");
                        }
                    });
                    Toast.makeText(AdminHome.this, "Internal Failure", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
    else if(mode==2)
    {
        dref.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                    DocumentSnapshot document = task.getResult();
                    if (document.exists()) {
                        Map<String,Object> m=new HashMap<>();
                        if(!pd.isEmpty())
                        {
                            m.put("pdesc",pd);
                        }
                        if(!pp.isEmpty())
                        {
                            m.put("pprice",pp);
                        }
                        if(!pq.isEmpty())
                        {
                            m.put("pstock",pq);
                        }
                        dref.update(m).addOnSuccessListener(new OnSuccessListener<Void>() {
                            @Override
                            public void onSuccess(Void aVoid) {
                                austatus.setVisibility(View.VISIBLE);
                                austatus.setText("Product Info Updated");
                            }
                        }).addOnFailureListener(new OnFailureListener() {
                            @Override
                            public void onFailure(@NonNull Exception e) {
                                austatus.setVisibility(View.VISIBLE);
                                austatus.setText("Product Info not Updated");
                            }
                        });
                    } else {
                        pName.setError("Product Name doesn't exist");
                    }
                } else {
                    pName.setError("Product Name doesn't exist");
                    Toast.makeText(AdminHome.this, "Internal Failure", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

更新后的logcat如下:

08-09 17:26:49.078 17647-17647/akshay.shoppingapplication D/MyTag: Sample / apples / 900 / 10 08-09 17:26:49.128 17647-17647/akshay.shoppingapplication D/MyTag: This fell on Isaac Newton's head and made students cry / apples / 90 / 5 08-09 17:26:49.164 17647-17647/akshay.shoppingapplication D/MyTag:fghckjd / banana / 90 / 20 08-09 17:26:49.192 17647-17647/akshay.shoppingapplication D/MyTag: abcd / grapes / 40 / 20 08-09 17:26:49.219 17647-17647/akshay.shoppingapplication D/MyTag: alphansos / mangoes / 120 / 10 08-09 17:26:49.250 17647-17647/akshay.shoppingapplication D/MyTag: Sample / perfume / 5000 / 5 08-09 17:26:49.275 17647-17647/akshay.shoppingapplication D/MyTag: desc / soap / 40 / 5

Answer 1

要解决这个问题，只需要下面几行代码:

cref.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<QuerySnapshot> task) {
        if (task.isSuccessful()) {
            for (DocumentSnapshot document : task.getResult()) {
                String pdesc = document.getString("pdesc");
                productdescription.add(pdesc);
                String pname = document.getString("pname");
                productname.add()pname;
                String pprice = document.getString("pprice");
                productprice.add(pprice);
                String pstock = document.getString("pstock");
                productquantity.add(pstock);
                Log.d("TAG", pdesc + " / " + pname + " / " + pprice + " / " + pstock); 
            }
            MyProductAdapter ma = new MyProductAdapter(
                productimage,
                ProductsAll.this,
                productname,
                productdescription,
                productquantity,
                productprice
            );
            prdctlist.setAdapter(ma);
        }
    }
});

logcat 中的输出将是:

This feels on Isaac Newton's head and made students cry / apples / 90 / 5
//and so on

编辑:

创建一个如下所示的模型类:

public class Product {
    private String pdesc, pname;
    private int pprice, pstock;

    public Product() { }

    public Product(String pdesc, String pname, int pprice, int pstock) {
        this.pdesc = pdesc;
        this.pname = pname;
        this.pprice = pprice;
        this.pstock = pstock;
    }

    public String getPdesc() { return pdesc; }
    public String getPname() { return pname; }
    public int getPprice() { return pprice; }
    public int getPstock() { return pstock; }
}

像这样使用模型类删除实际数据并添加新数据:

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionReference productsRef = rootRef.collection("products");
Model model = new Model("This feels on Isaac Newton's head and made students cry", "apples", 90, 5);
productsRef.document("apples").set(model);

然后要获取数据，请使用以下代码:

cref.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<QuerySnapshot> task) {
        if (task.isSuccessful()) {
            List<Product> productList = new ArrayList<>();
            for (DocumentSnapshot document : task.getResult()) {
                Product product = document.toObject(Product.class);
                productList.add(product);
                Log.d("TAG", product.getPdesc() + " / " + product.getPname() + " / " + product.getPprice() + " / " + product.getPstock()); 
            }
            MyProductAdapter ma = new MyProductAdapter(
                productimage,
                ProductsAll.this,
                productList
            );
            prdctlist.setAdapter(ma);
        }
    }
});

如您所见，我没有将 4 个列表传递给适配器，而是只传递了一个。所以不要忘记更改适配器类。