CODEWITHSUNDEEP
javaandroidandroid-asynctask
Nicholas Muir
Nicholas Muir

Reputation: 3114

AsyncTask when is onPostExecute() not called?

I am trying to ensure that I account for all possibilities to avoid errors for the user.

I have a AsyncTask that implements an interface and returns a response to the calling class in onPostExecute of the AsyncTask as below:

public class GetVideoInfoFromDataBase extends AsyncTask {

    Context context;
    private AsyncInterface asyncInterface;

    // Paginated list of results for alarm database scan
    static PaginatedScanList<AlarmDynamoMappingAdapter> results;

    // The DynamoDB object mapper for accessing DynamoDB.
    private final DynamoDBMapper mapper;

    public GetVideoInfoFromDataBase(Context context, AsyncInterface asyncInterface){
        mapper = AWSMobileClient.defaultMobileClient().getDynamoDBMapper();
        this.context = context;
        this.asyncInterface = asyncInterface;

    }

    @Override
    protected Object doInBackground(Object[] params) {
        System.out.println("The backgrond stuff is working 1");
        DynamoDBScanExpression scanExpression = new DynamoDBScanExpression();
        results = mapper.scan(AlarmDynamoMappingAdapter.class, scanExpression);
        return results;
    }

    @Override
    public void onPostExecute(Object obj) {

           asyncInterface.response((PaginatedScanList<AlarmDynamoMappingAdapter> )obj);
    }
}

Is there any time that onPostExecute would not be called meaning the interface would not return a value?

Thanks in advance for your help.

Upvotes: 2

Views: 108

Answers (1)

earthw0rmjim
earthw0rmjim

Reputation: 19417

onPostExecute() will run as long as doInBackground() returns and you did not cancel the task explicitly (by calling cancel() on your AsyncTask instance).

Technically, onPostExecute() will get called after (and if) the following line gets executed successfully:

return results;

As long as your process does not get killed in the meantime.

If you've cancelled your task, onCancelled() will be invoked instead of onPostExecute().

Upvotes: 2

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