All posts by coldstreams

Android Development, Documentation, General, Programming Method, Tips, Uncategorized

Update: Reading and writing text files with App Inventor

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I previously posted a short tutorial on writing to and reading from text files stored on an Android device, using an App Inventor app.

Unfortunately, as some comments noted, the file being created seems to disappear – the data is written and can be read back – but the file is no where to be found on the phone!

After some research, I now know where the file is – and also how to copy the file from the phone (or tablet) to your personal computer.  While the solution to finding and saving the file to your computer is ultimately easy, I need to update the tutorial and explain some things about the Android file system. You will also need to install a free app on your phone in order to copy the file to your computer.

I have posted an updated tutorial that explains the details and shows how to store your files in the right location, how to find them (they are hidden from most views), and how to copy them to your personal computer.

General, Uncategorized

App Inventor Alert: Problems loading projects?

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From the MIT App Inventor web site:

Summary: We have been having problems with storing “assets” image, sounds and other objects that you upload to your projects. We are working with Google to resolve these problems as soon as possible.

Things to be aware of:

If we fail to read an asset when you load your project, we substitute a zero-length file. Be careful exporting your projects, as assets may be missing from the “.aia” file exported. Make sure you keep a local copy of your assets on your own computer.

We have been making modifications to the system to mitigate the worst of the problems. In particular we will never serve up a missing asset to the “buildserver” when you package an App. This ensure that if you successfully package an App, the resulting APK is valid. If we fail to read an asset, you will get a “Build Failed” message. If this happens, just keep trying the build. It may work the second or third time around. If it never seems to work, you can remove your assets from your project and upload them again. This may help.

via Problems loading projects?.

App Inventor News, General, Uncategorized

December 8-14 is Computer Science Education Week

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The Computer Science Education Week coincides with the “Hour of Code” initiative. This example lesson is based on MIT’s Scratch (which is similar to App Inventor).

There are 33 introductory tutorials available for the “Hour of Code” project (teachers may optionally create their own as well).

One of the official tutorial opportunities is based on App Inventor.

Use caution in interpreting the hype over “Hour of Code”. It’s a primitive introduction to some limited programming concepts; many of the tutorials have limited association with computer science. If your expectations are set appropriately, its fine.

General, History, Software, Uncategorized

Google expected to introduce new Java compiler

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The upcoming Jack & Jill compilers in Android | Saikoa.

Most Android apps are written in the Java programming language. Google’s Android software development system converts “source code” (a text file) written in Java, into the code that runs on the Android device.

In many programming language systems, source code is converted into the “machine instructions” of the processor. The processor does not speak “Java” but speaks its own language. A program called a “compiler” converts the original program source code into the “machine language” of the processor.

Many programs for Windows, for example, have been converted into the individual instructions that are processed by an Intel or AMD processor. The “compiler” converts the program source code into a .exe file that contains the machine language instructions of the Intel and AMD processor.

But what if you wanted your program to run on a hardware device that has a Qualcomm or ARM processor?

Continue reading Google expected to introduce new Java compiler →

Products, Uncategorized

Inexpensive Android tablet and smart phone available

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Chances are, if you are writing App Inventor apps for Android, you already have an Android smart phone or tablet. If not, Amazon has slashed prices on their Amazon Fire Phone, 32GB (Unlocked GSM) and their Amazon Fire HD 7 tablet (but do see NOTE below!):

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NOTE – the Fire HD runs Android but its not a fully open Android tablet. However, there are some work arounds; more info on that here. Here is a CNet web page that shows specifically how to load other apps – there are some limitations so read the whole link. I do not own this tablet and have not tested it with App Inventor. Appears to be the same issue with the Fire Phone – Amazon restricts it but its just a matter of setting some options in Settings to open it up. Would be interesting to hear from others if they have App Inventor apps running on this tablet or phone. Seems like they should work!

Another excellent tablet option is the ASUS Google Nexus 7 Android Tablet (16gb) which is also available in 32 GB:  Nexus 7 from Google (7-Inch, 32 GB, Black) by ASUS (2013) Tablet. I have the ASUS Nexus 7 and really like it a lot.

Continue reading Inexpensive Android tablet and smart phone available →

App Inventor News, General, History, Software, Uncategorized

What are the hot programming languages for today

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Here is an easy to read report on which programming languages are now “hot” in the market for software developers: Don’t Rely On Salary Data To Pick A Programming Language To Learn – ReadWrite.

The pace of change in software development is rapid – popular languages today may already be fading.  Pay scales for some niche languages are very high (such as Ruby)- but the market opportunity might not be large or lengthy.

Web applications and mobile applications are the “hot” categories. Within those categories, there are a variety of currently popular software development tools:

Continue reading What are the hot programming languages for today →

General, Uncategorized

Facebook followers: Click on “Get Notifications” to stay up to date

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Thank you to those that are following these updates via Facebook.

Facebook tries to automatically figure out what posts you read. But if you do not “like”, “click on”, share or comment on pages that you have “Liked”, Facebook removes those pages from your daily “newsfeed”!  And that means pages like the App Inventor 2 Tutorial gradually disappear from your FB newsfeed!

There are two ways to fix this defect in Facebook.

1.  To insure that updates are posted to your newsfeed, click on “Like” on the App Inventor 2 FB page and then click on “Get Notifications” in the drop down menu:

GetNotifications

You can change this setting at any time by visiting the App Inventor 2 page.

Continue reading Facebook followers: Click on “Get Notifications” to stay up to date →