Problem with fetching data from SQLite in Android

Question

I was following this tutroial about using your own SQLite database. I did these steps as described in the tutorial:

Preparing my database
Copying the same EXACT DataBaseHelper class to my project package. You can see the class code there

Then, I just added one method to the DataBaseHelper class which is fetchData. It is simply fetching a whole table with the given name:

public Cursor fetchData(String table) {
String[] selectionArgs = new String[] {"*"};
return myDataBase.query(table, null, null, selectionArgs, null, null, null);
}

After that, in one of my activity classes I did this:

DataBaseHelper myDbHelper;
myDbHelper = new DataBaseHelper(this);

try { 

    myDbHelper.createDataBase();

} catch (IOException ioe) {

    throw new Error("Unable to create database");

}
try {

    myDbHelper.openDataBase();

} catch (SQLException sqle) {

    throw sqle;

}

TextView txt = (TextView) findViewById(R.id.txt);
try {
//I will use my method to fetch a table named: myTable      
    Cursor c = myDbHelper.fetchData("myTable"); 
    if((Object)c.getCount() != null)
        txt.setText(c.getCount());
    else
        txt.setText("null");
} catch(Exception e) {
    txt.setText("error");

}

However, I keep getting 'error' in the TextView. Is there a problem in my way?

iTurki · Accepted Answer · 2011-07-04 05:46:50Z

1

My problem is nothing related to SQLite. It was silly mistake :-\

The error is in the second line here:

if((Object)c.getCount() != null)
    txt.setText(c.getCount());

It must be like this:

    txt.setText(""+c.getCount());

the setText() method accepts a ChaSequence and the getCount() method returns Integer which are not in compatible type. you can work around that tha easy way, by adding empty string :)

Thanks Guys.

answered Jul 4, 2011 at 5:46

iTurki

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Comments

Sarwar Erfan · Accepted Answer · 2011-07-03 07:13:06Z

0

public Cursor fetchData(String table) {
     return myDataBase.query(table, null, null, null, null, null, null);
}

Seems you got wrong idea about the selectionArgs parameter. In documentation, it says:

You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.

answered Jul 3, 2011 at 7:13

Sarwar Erfan

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4 Comments

iTurki Over a year ago

That was my first trial but it didn't work. I tried this instead and got the same. Thanks for your try.

Sarwar Erfan Over a year ago

As your app is going to the catch part, check what exception you are getting.

iTurki Over a year ago

I figured it out :) See my answer

iTurki Over a year ago

Unfortunately, I can't answer before 7 hours :(

Philip Sheard · Accepted Answer · 2011-07-03 11:33:59Z

0

Your trying to cast an int as an Object, then comparing the cast value to null. I would say that you code is likely to break right there.

answered Jul 3, 2011 at 11:33

Philip Sheard

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