Thiago Ferrao Thiago Ferrao - 1 year ago 79
Android Question

Error casting Object[] to ContentValues[]

I'm following a tutorial about content providers and, in a specific code, they inserted some data using a

method. They also used a Vector variable (
) to store all the

Code that was mentioned:

if (cVVector.size() > 0) {
ContentValues[] cvArray = new ContentValues[cVVector.size()];
mContext.getContentResolver().bulkInsert(WeatherEntry.CONTENT_URI, cvArray);

Then, I tried to reduce the code by casting
, but I'm getting an error.

Code edited by me:

if (cVVector.size() > 0) {
mContext.getContentResolver().bulkInsert(WeatherEntry.CONTENT_URI, (ContentValues[]) cVVector.toArray());

Error that I'm getting:

Process: com.example.thiago.sunshine, PID: 9848
java.lang.RuntimeException: An error occured while executing doInBackground()
Caused by: java.lang.ClassCastException: java.lang.Object[] cannot be cast to android.content.ContentValues[]

Finally, my question is: Why I can't do a casting between an
and a

Obs.: English is not my mother tongue, please excuse any errors.

Answer Source

You can't cast Object[] to ContentValues[], because there is no relationship between these two types. They are different array types.

Just like you can cast an Object to a String like this :

Object a = "aa";
String b = (String) a;

because String is a subclass of Object.

But you can't do this :

Object[] ar = new Object[]{"aa", "bb"};
String[] br = (String[]) ar;

You will find this is OK in compile time, but will not work in runtime. The forced type conversion in JAVA may only work for single object not array.

You can replace your code with:

if (cVVector.size() > 0) {
   mContext.getContentResolver().bulkInsert(WeatherEntry.CONTENT_URI, (ContentValues[]) cVVector.toArray(new ContentValues[1]));

Hope this can help you.