我一直在开发一个 Android 应用程序，它需要从 SQL 数据库检索一些信息。最初我试图在databaseHelper1类中形成一个名为getRemainingAmount()的函数来做到这一点，但这导致了错误
FATAL EXCEPTION: main Process: com.carrot.wallet, PID: 30591 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.carrot.wallet/com.carrot.wallet.MainActivity}: android.view.InflateException: Binary XML file line #10 in com.carrot.wallet:layout/activity_main: Binary XML file line #10 in com.carrot.wallet:layout/activity_main: Error inflating class fragment at
之后，当我尝试从 addTransaction 类获取数据时，我开始收到以下错误:
2020-05-30 09:25:12.946 11239-11239/com.carrot.wallet E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.carrot.wallet, PID: 11239
android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 0
at android.database.AbstractCursor.checkPosition(AbstractCursor.java:468)
at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
at com.carrot.wallet.AddTransaction$4.onClick(AddTransaction.java:102)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
这是我的databaseHeleper1类，其中包含函数getRemainingAmount()
package com.carrot.wallet.Database;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import androidx.annotation.Nullable;
public class DatabaseHelper1 extends SQLiteOpenHelper {
private static final int version = 3;
private static final String name = "YEAR_DETAILS";
private static final String COL0 = "YEAR";
private static final String COL1 = "MONTH";
private static final String COL2 = "SPENT";
private static final String COL3 = "REMAINING";
private static final String TAG = "Database Helper 1";
public DatabaseHelper1(@Nullable Context context) {
super(context, name, null, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.d(TAG , "Database 1 is being created");
String create_table = "CREATE TABLE "+name+"("+
COL0+" INTEGER, "+
COL1+" TEXT, "+
COL2+" DOUBLE, "+
COL3+" DOUBLE);";
db.execSQL(create_table);
}
@Override
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+name);
onCreate(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
private boolean createMonth(String month , String year){
Log.d(TAG , "month row is being created");
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL0 , year);
contentValues.put(COL1 , month);
contentValues.put(COL2 , 0.0);
contentValues.put(COL3 , 0.0);
long result = db.insert(name,null , contentValues);
return result != -1;
}
public boolean spentChange(String month , String year , Double newAmount){
Log.d(TAG , "spent amount is being changed");
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COL2 , newAmount);
long result = db.update(name, values , "MONTH = ? AND YEAR = ?", new String[]{month , year});
return result != -1;
}
public boolean remainingChange(String month ,String year, Double newAmount){
Log.d(TAG , "Remaining amount is being changed");
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues =new ContentValues();
contentValues.put(COL3 , newAmount);
long result = db.update(name , contentValues , "MONTH = ? AND YEAR = ?" , new String[]{month , year});
return result != -1;
}
public void checkExistance(String month, String year){
Log.d(TAG , "Checking if month already exits");
SQLiteDatabase database = this.getWritableDatabase();
Cursor cur = database.query(name , null , "MONTH = ? AND YEAR = ?" , new String[]{month , year} , null , null , null);
System.out.println(cur);
if(cur.getCount() <= 0) {
boolean b = createMonth(month , year);
if(b)
Log.d(TAG , "checkExistance: failed to create month");
else
Log.d(TAG, "checkExistance: month created successfully");
}
}
public Cursor getdata(){
SQLiteDatabase db = this.getReadableDatabase();
String query = "SELECT * FROM YEAR_DETAILS;";
return db.rawQuery(query , null);
}
public Cursor getSpentAmount(String month , String year){
SQLiteDatabase db = this.getWritableDatabase();
String query = "SELECT * FROM YEAR_DETAILS WHERE MONTH = " + month+ " AND YEAR = "+year;
return db.rawQuery(query , null);
}
public Cursor getRemainingAmount(String month , String year){
SQLiteDatabase db = this.getReadableDatabase();
Cursor cur = db.query(name , new String[]{COL3} , "MONTH = ? AND YEAR = ?" , new String[]{month , year} , null , null , null);
return cur;
}
}
AddTransaction 类(我在其中检索数据)
package com.carrot.wallet;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import com.carrot.wallet.ArrayListClasses.add_transaction_data;
import com.carrot.wallet.Database.DatabaseHelper1;
import com.carrot.wallet.Database.DatabaseHelper2;
import com.carrot.wallet.recyclerview.at_btn_adapter;
import java.util.ArrayList;
import java.util.Calendar;
import com.carrot.wallet.recyclerview.onClickRecyclerButtion;
public class AddTransaction extends AppCompatActivity {
int type1 ;
int type2;
double amount;
ArrayList<add_transaction_data> data;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_transaction);
ActionBar actionBar = getSupportActionBar();
assert actionBar != null;
actionBar.hide();
populateList();
final ImageButton cancel = findViewById(R.id.at_btn_cancel);
final EditText EditAmount = findViewById(R.id.at_enter_amount);
ImageButton save = findViewById(R.id.at_btn_save);
ImageButton income = findViewById(R.id.at_btn_income);
ImageButton loan = findViewById(R.id.at_btn_loan);
RecyclerView recyclerView = findViewById(R.id.at_btn_recyclerview);
recyclerView.setLayoutManager(new GridLayoutManager(this , 5));
recyclerView.setAdapter(new at_btn_adapter(data, new onClickRecyclerButtion() {
@Override
public void onPositionClicked(int position) {
type1 = 2;
type2 = position;
}
}));
income.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
type1 = 1;
type2 = -1;
}
});
loan.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
type1 = 1;
type2 = -2;
}
});
context = this;
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
System.out.println("it is all cool here");
DatabaseHelper1 databaseHelper1 = new DatabaseHelper1(getBaseContext());
DatabaseHelper2 databaseHelper2 = new DatabaseHelper2(getBaseContext());
double amount = Double.parseDouble(EditAmount.getText().toString());
System.out.println(amount);
Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
String m = changeString(month);
System.out.println(type1);
String mRamount = "ds";
if(type1 == 1){
SQLiteDatabase database = databaseHelper1.getReadableDatabase();
String ca = "SELECT * FROM YEAR_DETAILS WHERE MONTH = " + month+ " AND YEAR = "+year;
Cursor cursor = database.rawQuery(ca , null);
mRamount = cursor.getString(1);
System.out.println(mRamount);//printing amount.
}
startActivity(new Intent(AddTransaction.this , MainActivity.class));
}
});
cancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(AddTransaction.this , MainActivity.class));
}
});
}
void populateList(){
data = new ArrayList<>();
data.add(new add_transaction_data("Add" , R.drawable.ic_add_black_24dp));
data.add(new add_transaction_data("Shopping" , R.drawable.at_ic_shopping));
data.add(new add_transaction_data("Food" , R.drawable.at_ic_food));
data.add(new add_transaction_data("Traveling" , R.drawable.at_ic_travel));
data.add(new add_transaction_data("Education" , R.drawable.at_ic_education));
data.add(new add_transaction_data("Energy" , R.drawable.at_ic_energy));
data.add(new add_transaction_data("House" , R.drawable.at_ic_home));
data.add(new add_transaction_data("Fitness" , R.drawable.at_ic_sports));
data.add(new add_transaction_data("Personal" , R.drawable.at_ic_personal));
data.add(new add_transaction_data("Other" , R.drawable.at_ic_other));
}
String changeString(int month){
String m;
switch (month){
case 0:
m = "January";
break;
case 1:
m = "Feburary";
break;
case 2:
m = "March";
break;
case 3:
m = "April";
break;
case 4:
m = "May";
break;
case 5:
m = "June";
break;
case 6:
m = "July";
break;
case 7:
m = "August";
break;
case 8:
m = "September";
break;
case 9:
m = "October";
break;
case 10:
m = "November";
break;
case 11:
m = "December";
break;
default:
m = " ";
}
return m;
}
}
activity_main xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<fragment
android:id="@+id/fragNavHost"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="@navigation/mobile_navigation" />
<me.ibrahimsn.lib.SmoothBottomBar
android:elevation="30dp"
android:id="@+id/bottom_nav"
android:layout_width="match_parent"
app:iconTint="@color/colorPrimary"
app:indicatorColor="#EFEFEF"
app:iconTintActive="@color/colorPrimaryDark"
app:textColor="@color/colorPrimaryDark"
android:layout_height="70dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="@menu/bottom_navigation_bar"/>
</androidx.constraintlayout.widget.ConstraintLayout>
有人可以帮助我了解导致这两个错误的原因吗？
最佳答案
在 getData() 方法中，有两个分号
String query = "SELECT * FROM YEAR_DETAILS;";
尝试将其更改为
String query = "SELECT * FROM YEAR_DETAILS"
我建议您迁移到 Room 库
关于java - android 中的 SQL 数据库，请求索引 -1，大小为 0，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/62097688/