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parse-platformpffile

How to obtain data directly from PFFile without warning

I am using PFFile to store images. If the image is already downloaded, I want to access it directly. If not, I want to use the background methods. However, if I use getData, I get the following warning:

Warning: A long-running operation is being executed on the main thread. 
 Break on warnBlockingOperationOnMainThread() to debug.

Since I know that the data is available, this warning is unnecessary and clutters my log. Is there any way to access PFFile's data without triggering a warning?

Solution

  • You are getting the warning because the data is not available locally and getData is a synchronous call to fetch the data from the server. When getData is called, it blocks the main thread - the UI - and stops all app interaction until the data downloads, which is why you are getting the error. Generally, blocking the UI to do a background operation, such as downloading, is very much frowned upon.

    I would use the isDataAvailable property of PFFile to check if the data is available locally. If it isn't, use getDataInBackgroundWithBlock: to fetch the data in the background. You can use the completion method supplied by that call to update your imageView.

    UPDATE - You can also wrap the getData call in a dispatch_async block, which will move the operation to another thread, therefore removing it from the main thread and getting rid of the warning.