Android SQLite：如何更新表

Question

Can anyone confirm whether my approach to updating the database is correct? The code is called, no errors are produced, however the database is not updated. I really would appreciate some help, been working on this for days and days.

My update code:

public int updateContact(CountElement counter) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(TITLE, counter.getTitle());
    values.put(DESC, counter.getDescription());
    values.put(COUNT, counter.getCounterValue());

    Bitmap bmp = counter.getIcon();
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] byteArray = stream.toByteArray();
    values.put(ICON, byteArray);

    values.put(LabelColor, counter.getLabelColor());

    // updating row
    return db.update(TABLE_NAME, values, KEY_ID + " = ?",
            new String[] { String.valueOf(counter.getID()) });
}

How I add the CountElement:

void addContact(CountElement counter) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(TITLE, counter.getTitle()); // Counter title
    values.put(DESC, counter.getDescription()); // Counter desc
    values.put(COUNT, counter.getCounterValue());

    Bitmap bmp = counter.getIcon();
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] byteArray = stream.toByteArray();
    values.put(ICON, byteArray);

    values.put(C, counter.getLabelColor());

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

My CountElement class:

public class CountElement {
    private String title;
    private String description;
    public int counterValue;
    private Bitmap icon;
    private int labelColorInt;
    private int _id;

    public CountElement(int id, String title, String description,
            int counterValue, Bitmap iconID, int labelColorInt) {
        this._id = id;
        this.title = title;
        this.description = description;
        this.counterValue = counterValue;
        this.icon = iconID;
        this.labelColorInt = labelColorInt;
    }

    public CountElement(String title, String description, int counterValue,
            Bitmap iconID, int labelColorInt) {
        this.title = title;
        this.description = description;
        this.counterValue = counterValue;
        this.icon = iconID;
        this.labelColorInt = labelColorInt;
    }

    public CountElement() {
    }

    // The getters and setters:
    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    // getting ID
    public int getID() {
        return this._id;
    }

    // setting id
    public void setID(int id) {
        this._id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public int getCounterValue() {
        return counterValue;
    }

    public void setCounterValue(int counterValue) {
        this.counterValue = counterValue;
    }

    public Bitmap getIcon() {
        return icon;
    }

    public void setIcon(Bitmap icon) {
        this.icon = icon;
    }

    public int getLabelColor() {
        return labelColorInt;
    }

    public void setLabelColor(int labelColorInt) {
        this.labelColorInt = labelColorInt;
    }
}

Any ideas?

Much appreciated. Thanks!

Answer 1

The problem is that you forgot to close the database after you finish updating it, your update contact should be like this:

public int updateContact(CountElement counter) {
    SQLiteDatabase db = this.getWritableDatabase();

    ...

    // updating row
    int ret = db.update(TABLE_NAME, values, KEY_ID + " = ?",
            new String[] { String.valueOf(counter.getID()) });
    db.close();
    return ret;
}

Answer 2

The easiest way to do operations on Sqlite

use GREENDAO OR ORMSQLITE

for GREENDAO you have green dao generator to generate tables and db easily

Answer 3

have you try the insert method? is it works?as @Krypton said you forget to close the db. you can debug with raw sql query string in an sqlite client like sqlitemanager,and find if it's work.

Answer 4

Assuming the id field is an auto-generater primary key field, you need to capture the generated value on insert. In addContact() , replace

db.insert(TABLE_NAME, null, values);

with something like

long id = db.insert(TABLE_NAME, null, values);
counter.setID(id);

Otherwise the id comes out as default value 0 and it won't match any rows to update in the database.