java.lang.NumberFormatException：无效的int：" null"

问题描述

方法getAllActivities（）必须以数组列表格式返回数据库中的所有活动
但我得到：java.lang.NumberFormatException：无效的int：null，
at activity.setActivityType（Integer.parseInt（cursor.getString（1）））;
我不知道有什么问题

The method getAllActivities() must return all activities from database in array list formatBut I got: java.lang.NumberFormatException: Invalid int: "null",at activity.setActivityType(Integer.parseInt(cursor.getString(1)));I don't know what is wrong

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import com.yast.util.Constants;
import com.yast.util.Utils;
import java.util.ArrayList;
import java.util.List;


public class DatabaseHandler extends SQLiteOpenHelper {
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "YastDB.db";

    // Activities table name
    private static final String TABLE_ACTIVITIES = "Activities";

    // Activities Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_ACTIVITYTYPE = "ActivityType";
    private static final String KEY_HARTRATE = "HartRate";
    private static final String KEY_HARTBATNO = "HartBatNo";
    private static final String KEY_DISTANCE = "Distance";
    private static final String KEY_SPEED = "Speed";
    private static final String KEY_STRIDES = "Strides";
    private static final String KEY_STARTDATETIME = "StartDateTime";
    private static final String KEY_ENDDATETIME = "EndDateTime";
    public static final String  KEY_CURRENTDATETIME = "CurrentDateTime";

    private String[] PROJECTION = new String[]{ KEY_ID,
            KEY_ACTIVITYTYPE, KEY_HARTRATE,KEY_HARTBATNO, KEY_DISTANCE,
            KEY_SPEED,KEY_STRIDES,KEY_STARTDATETIME,KEY_ENDDATETIME
            ,KEY_CURRENTDATETIME};

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

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_Activitys_TABLE = "CREATE TABLE " + TABLE_ACTIVITIES + "("
                + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
                KEY_ACTIVITYTYPE + " INTEGER,"+
                KEY_HARTRATE + " INTEGER, "+
                KEY_HARTBATNO + " INTEGER,"+
                KEY_DISTANCE + " INTEGER," +
                KEY_SPEED + " INTEGER," +
                KEY_STRIDES + " INTEGER," +
                KEY_STARTDATETIME + " TEXT," +
                KEY_ENDDATETIME + " TEXT," +
                KEY_CURRENTDATETIME + " TEXT" +
                ")";
        db.execSQL(CREATE_Activitys_TABLE);
    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_ACTIVITIES);

        // Create tables again
        onCreate(db);
    }

    //CRUD operations (Create, Read, Update and Delete)
    // Adding new activity
    public void addActivity(ActivityEntity activity) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_ACTIVITYTYPE, activity.getActivityType()); // Activity type
        values.put(KEY_HARTRATE, activity.getHartRate());
        values.put(KEY_HARTBATNO, activity.getHartBatNo());
        values.put(KEY_DISTANCE, activity.getDistance());
        values.put(KEY_SPEED, activity.getSpeed());
        values.put(KEY_STRIDES, activity.getStrides());
        values.put(KEY_STARTDATETIME,activity.getStartDateTime().toString());
        values.put(KEY_ENDDATETIME, activity.getEndDateTime().toString());
        values.put(KEY_CURRENTDATETIME, activity.getCurrentDateTime().toString());

        // Inserting Row
        db.insert(TABLE_ACTIVITIES, null, values);
        db.close(); // Closing database connection

    }

    // Getting single Activity
    /*
    The following method getActivity() will read single contact row.
    It accepts id as parameter and will return the matched row from the database.
     */
    public ActivityEntity getActivity(int id) {
        ActivityEntity activity = null;
        SQLiteDatabase db = this.getReadableDatabase();

        String where = KEY_ID + "=?";
        String[] selectionArg = new String[]{String.valueOf(id)};

        Cursor cursor = db.query(TABLE_ACTIVITIES, PROJECTION, where, selectionArg,
 null, null, null, null);
        if (cursor != null) {
            cursor.moveToFirst();

            activity = new ActivityEntity(Integer.parseInt(cursor.getString(0)),
                    Integer.parseInt(cursor.getString(1)),
                    Integer.parseInt(cursor.getString(2)),
                    Integer.parseInt(cursor.getString(3)),
                    Integer.parseInt(cursor.getString(4)),
                    Integer.parseInt(cursor.getString(5)),
                    Integer.parseInt(cursor.getString(6)),
                    cursor.getString(7),
                    cursor.getString(8),
                    cursor.getString(9));
        }
        return activity;
    }

    // Getting All Activities
    public ArrayList<ActivityEntity> getAllActivitys() {

        ArrayList<ActivityEntity> activitiesList = new ArrayList<ActivityEntity>();
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.query(TABLE_ACTIVITIES, PROJECTION, null, null, null, null, null, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                ActivityEntity activity = new ActivityEntity();
                activity.setID(Integer.parseInt(cursor.getString(0)));
                activity.setActivityType(Integer.parseInt(cursor.getString(1)));
                activity.setHartRate(Integer.parseInt(cursor.getString(2)));
                activity.setHartBatNo(Integer.parseInt(cursor.getString(3)));
                activity.setDistance(Integer.parseInt(cursor.getString(4)));
                activity.setSpeed(Integer.parseInt(cursor.getString(5)));
                activity.setStrides(Integer.parseInt(cursor.getString(6)));
                activity.setStartDateTime(cursor.getString(7));
                activity.setEndDateTime(cursor.getString(8));
                activity.set_currentDateTime(cursor.getString(9));

                // Adding activity to list
                activitiesList.add(activity);
            } while (cursor.moveToNext());

        }
        return activitiesList;
    }


    public int getActivitiesCount() {

        String countQuery = "SELECT  * FROM " + TABLE_ACTIVITIES;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        cursor.close();

        // return count
        return cursor.getCount();
    }

    // Updating single Activity
    public int updateActivity(ActivityEntity activity) {
            SQLiteDatabase db = this.getWritableDatabase();

            String where = KEY_ID + "=?";

            ContentValues values = new ContentValues();
            values.put(PROJECTION[1], activity.getActivityType());
            values.put(PROJECTION[2], activity.getHartRate());
            values.put(PROJECTION[3], activity.getHartBatNo());
            values.put(PROJECTION[4], activity.getDistance());
            values.put(PROJECTION[5], activity.getSpeed());
            values.put(PROJECTION[6], activity.getStrides());
            values.put(PROJECTION[7], activity.getStartDateTime().toString());
            values.put(PROJECTION[8], activity.getEndDateTime().toString());
            values.put(PROJECTION[9], activity.getCurrentDateTime().toString());


            // updating row
            return db.update(TABLE_ACTIVITIES, values, where, new String[] { String.valueOf(activity.getID()) });
    }

    public void deleteActivity(ActivityEntity activity)
    {
        String where = KEY_ID + "=?";

        SQLiteDatabase db = this.getWritableDatabase();
        db.delete(TABLE_ACTIVITIES, where,
                new String[] { String.valueOf(activity.getID()) });
        db.close();
    }

    public void bulkInsert(ArrayList<ActivityEntity> arrayOfActivities) {
        SQLiteDatabase db = this.getWritableDatabase();
        String sql = "INSERT INTO "+ TABLE_ACTIVITIES +" VALUES (?,?,?,?,?,?,?,?,?,?);";
        SQLiteStatement statement = db.compileStatement(sql);
        db.beginTransaction();
       for (ActivityEntity a : arrayOfActivities ) {
            statement.clearBindings();
            statement.bindLong(1, (long) a.getID());
            statement.bindLong(2, (long) a.getActivityType());
            statement.bindLong(3, (long) a.getHartRate());
            statement.bindLong(4, (long) a.getHartBatNo());
            statement.bindLong(5, (long) a.getDistance());
            statement.bindLong(6, (long) a.getSpeed());
            statement.bindLong(7, (long) a.getStrides());
            statement.bindString(8, a.getStartDateTime());
            statement.bindString(9, a.getEndDateTime());
            statement.bindString(10,a.getCurrentDateTime());

            statement.clearBindings();
            statement.execute();
        }
        db.setTransactionSuccessful();
        db.endTransaction();
    }


}

ActivityEntity.java calss：

ActivityEntity.java calss:

import com.yast.util.Constants;
import com.yast.util.Utils;
import java.util.Date;

public class ActivityEntity {

    int id;
    int activityType;
    int hartRate;
    int hartBatNo;
    int distance;
    int speed;
    int strides;
    String startDateTime;
    String endDateTime;
    String currentDateTime;

    public ActivityEntity(){

    }
    // constructor
    public ActivityEntity(int Id, int activityType, int hartRate, int _hartBatNo, int distance, int speed, int strides, String startDateTime, String endDateTime, String currentDateTime){
        this.id = Id;
        this.activityType = activityType;
        this.hartRate = hartRate;
        this.hartBatNo = _hartBatNo;
        this.distance = distance;
        this.speed = speed;
        this.strides = strides;
        this.startDateTime = startDateTime;
        this.endDateTime = endDateTime;
        this.currentDateTime = currentDateTime;
    }
    public void setID(int id){
        this.id = id;
    }
    public int getID(){
        return this.id;
    }
    public void setActivityType(int activityType){
        this.activityType = activityType;
    }
    public int getActivityType(){
        return this.activityType;
    }
    public void setHartRate(int hartRate){
        this.hartRate = hartRate;
    }

    public int getHartRate(){
        return this.hartRate;
    }
    public void setHartBatNo(int hartBatNo){
        this.hartBatNo = hartBatNo;
    }
    public int getHartBatNo(){
        return this.hartBatNo;
    }

    public void setDistance(int distance){
        this.distance = distance;
    }

    public int getDistance(){
        return this.distance;
    }

    public void setSpeed(int speed){
        this.speed = speed;
    }

    public int getSpeed(){
        return this.speed;
    }

    public void setStrides(int strides){
        this.strides = strides;
    }

    public int getStrides(){
        return this.strides;
    }

    public void setStartDateTime(String startDateTime){
        this.startDateTime = startDateTime;
    }

    public String getStartDateTime(){
        return this.startDateTime;
    }

    public void setEndDateTime(String endDateTime){
        this.endDateTime = endDateTime;
    }

    public String getEndDateTime(){
        return this.endDateTime;
    }

    public void set_currentDateTime(String currentDateTime){
        this.currentDateTime = currentDateTime;
    }
    public String getCurrentDateTime(){
        return this.currentDateTime;
    }

    @Override
    public String toString() {
        return "ActivityEntity{" +
                "id=" + id +
                ", activityType=" + activityType +
                ", hartRate=" + hartRate +
                ", hartBatNo=" + hartBatNo +
                ", distance=" + distance +
                ", speed=" + speed +
                ", strides=" + strides +
                ", startDateTime='" + startDateTime + '\'' +
                ", endDateTime='" + endDateTime + '\'' +
                ", currentDateTime='" + currentDateTime + '\'' +
                '}';
    }
}

推荐答案

in你的代码，如果 cursor.getString（int num）返回 null ，那么将抛出 NumberFormatException 。

in your code, if cursor.getString(int num) returns null, then Integer.parseInt(String str) will throw NumberFormatException.

为了避免这种情况，你应该有检查 cursor.getString（int num）返回的内容。

To avoid this, you should have check for what the cursor.getString(int num) returns.

或者，你可以使用 try-catch 并在 catch 中打印相应的消息，如果你得到 NumberFormatException 。

OR, you can use try-catch and print the appropriate message in catch if you'll get NumberFormatException.

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