Author: Luca Zanini
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New Astronomy category in this blog
In the last 4 years I have not used this blog but now I want to resume publishing the photos taken with my new telescope.Astronomy has been a my hobby since I was a child, unfortunately I had to stop for many years and now I would like to start observing the sky again. On…
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Saving and reading files in the internal storage
You can save and read files in the internal storage as private files which only your app can see except for other apps with root privileges.
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The class LruCache to manage a cache of bitmap objects
The intensive use of many images in an app can create difficulties to the responsiveness and to memory, shown by warnings like ANR (Application Not Responding) or errors like OutOfMemoryError.
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Avoiding too frequent updates to the views
In Android in order to avoid to do too work in the main thread, most of the operations should be carried out in a secondary thread or a class that extends AsyncTask; then the final results are reported in some view to be shown to the user using Activity.runOnUiThread(Runnable) or View.post(Runnable) (see Processes and Threads)…
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Golden Rolly
I published an app in Google Play Store named Golden Rolly, it is a game of the category puzzle and you can find a short video presentation here.
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Resetting the preferences on first launch of an app
If you want to reset or change preferences of an app at the first start here is an example of code you can put in an event as onCreate of the main activity:
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Restoring complex objects at restart of an activity
In an android app an activity is created and then destroyed, for example when the user open another activity or when the user presses the back button, later the user opens again the same activity that is is recreated using the data saved before the earlier destruction of the activity. The data are saved in…
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Stopping the threads
Starting a thread is very easy in java, after you create it you need to call the method start(), for example: Thread myThread = new Thread(new MyRunnable()); myThread.start(); where MyRunnable is a class implementing the Runnable interface overidden the method run().
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List of the sensors in a device
In December 2012 I wrote a post about an app that displays the sensor list in an android device, now after about a year and a half the API 19 have new sensor types and methods and I thought to update the app.