Question

我是android的新手。我试图在edittext中获取浮动值并将其存储在数据库中。然后我得到了那些存储值的总数。但我没有得到小数点后的值。这是我的代码......

package com.example.usaukglu.tablayoyt;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


public class Income extends AppCompatActivity implements View.OnClickListener {

TextView amount, payer, note, show;
EditText edi_amount, payer_name, edit_note;
Button save, cancel;
DatabaseHandler db;

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

    save = (Button) findViewById(R.id.save);
    cancel = (Button) findViewById(R.id.cancel);

    amount = (TextView) findViewById(R.id.amount);
    payer = (TextView) findViewById(R.id.payer);
    note = (TextView) findViewById(R.id.note);
    show = (TextView) findViewById(R.id.show);

    edi_amount = (EditText) findViewById(R.id.edit_amount);
    payer_name = (EditText) findViewById(R.id.edit_payer);
    edit_note = (EditText) findViewById(R.id.edit_note);
    //date= (EditText) findViewById(R.id.date);

    db = new DatabaseHandler(this);

    save.setOnClickListener(this);
    cancel.setOnClickListener(this);
}

@Override
public void onClick(View view) {
    if (view.getId() == R.id.save) {
        String amounts,payers,notes;
        amounts=edi_amount.getText().toString();
        payers= payer_name.getText().toString();
        notes= edit_note.getText().toString();
        if(amounts.isEmpty())
        {
           edi_amount.setError("Amounts should not be blank");
        }
        else  if (payers.isEmpty()){
            payer_name.setError("Payer name should not be blank");
        }
        else {
            Double a =new Double(amounts);
            DataProvider provider = new DataProvider(""+a, payers, notes);
            db.addInformation(provider);
            Intent i = new Intent(this, MainActivity.class);
            startActivity(i);
        }
    }


    if (view.getId() == R.id.cancel) {
        Intent i =new Intent(this,MainActivity.class);
        startActivity(i);
    }


    }

public void show(String data) {
    show.setText(data);
}

}

这是dataProvider类：

package com.example.usaukglu.tablayoyt;

public class DataProvider {
private String money;
private String name;
private String desc;

public DataProvider(String money, String name, String desc) {
    this.money = money;
    this.name = name;
    this.desc = desc;
}

public String getMoney() {
    return money;
}

public void setMoney(String money) {
    this.money = money;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getDesc() {
    return desc;
}

public void setDesc(String desc) {
    this.desc = desc;
}
}

DatabaseHandler类：

package com.example.usaukglu.tablayoyt;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import static com.example.usaukglu.tablayoyt.R.id.amount;
import static com.example.usaukglu.tablayoyt.R.id.note;
import static com.example.usaukglu.tablayoyt.R.id.payer;



public class DatabaseHandler extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "income.db";
public static final String TABLE_NAME = "income_table";
public static final String ID="id";
public static final String AMOUNT = "amount";
public static final String PAYER_NAME = "payer";
public static final String NOTE = "note";

public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
    String query = "CREATE TABLE " + TABLE_NAME +
            "(" +ID+ " integer primary key autoincrement, " + AMOUNT + " real, " + PAYER_NAME + " text, " + NOTE + " text " + ")";
    sqLiteDatabase.execSQL(query);

}

@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    onCreate(sqLiteDatabase);

}

public void addInformation(DataProvider provider){
    SQLiteDatabase db = getWritableDatabase();
    ContentValues values=new ContentValues();
    values.put(AMOUNT,provider.getMoney());
    values.put(PAYER_NAME,provider.getName());
    values.put(NOTE,provider.getDesc());
    db.insert(TABLE_NAME, null, values);
    db.close();

}
public Cursor display()
{
    SQLiteDatabase sqLiteDatabase=getReadableDatabase();
    Cursor res= sqLiteDatabase.rawQuery("SELECT * FROM "+TABLE_NAME,null);
    return res;
}
public double getTotalOfAmount() {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor c = db.rawQuery("SELECT SUM(AMOUNT) FROM " + TABLE_NAME, null);
    c.moveToFirst();
    double i = c.getInt(0);
    c.close();
    return i;
}
}

FragmentIncome类我想要显示数据： package com.example.usaukglu.tablayoyt;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class FragmentIncome extends Fragment {
ListView list;
private DatabaseHandler handler;
private SQLiteDatabase database;
private List<DataProvider> amountList;
private ListDataAdaptar listDataAdaptar;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view =inflater.inflate(R.layout.fragment_income,container,false);
    list=(ListView) view.findViewById(R.id.listView);
    amountList=new ArrayList<>();
    handler=new DatabaseHandler(getContext());
    database=handler.getReadableDatabase();

    Cursor cursor=handler.display();
    if(cursor.moveToFirst()){
        do {
            String amount,payer,note;
            amount= cursor.getString(cursor.getColumnIndex(handler.AMOUNT));
          payer=cursor.getString(cursor.getColumnIndex(handler.PAYER_NAME));
            note=cursor.getString(cursor.getColumnIndex(handler.NOTE));
            DataProvider provider=new DataProvider(amount,payer,note);
            amountList.add(provider);
            listDataAdaptar=new ListDataAdaptar(getContext(),R.layout.display_income_row,amountList);
            list.setAdapter(listDataAdaptar);

        }while (cursor.moveToNext());
    }
    return view;

}
}

Answer 1

您正在数据库中使用String变量。在表中使用float数据类型来运行SUM查询。

您的DataProvider类应该是这样的 -

public class DataProvider {
private Float money;
private String name;
private String desc;


public DataProvider(Float money, String name, String desc) {
    this.money = money;
    this.name = name;
    this.desc = desc;
}

public Float getMoney() {
    return money;
}

public void setMoney(Float money) {
    this.money = money;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getDesc() {
    return desc;
}

public void setDesc(String desc) {
    this.desc = desc;
}
}

没有得到android中小数点后的数字

1 个答案: