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Pebble: How to load random string from resource

By , 02/15/2015 10:10 PM

There’s no doubt that Firefly is a greatest TV series in the history of all creation. That is why when I was learning resource handling in Pebble SDK I have decided to create a watchface that would display a random quote from Firefly. And thanks to Bill Hatcher of http://cubemonkey.net/quotes/ I obtained a plain TXT file with almost 500 quotes.

The file is in the format "quote1%quote2%quote3..." e.g. there is a “%” separator between the quotes, so I quickly wrote a small script that gives me a position of each percentage sign within the file, so I can create an array of the positions in my C code for Pebble:

#define NO_OF_QUOTES 472
int aQuotePointers[NO_OF_QUOTES] = {0, 206, 354, 417, 480, 554, 662, 695,... 88825}

which basically gave me position of each quote in the file and which I prepended with 0 and appended with filesize. Then I added the resource to my project (in CloudPeble environment it’s as easy as loading a BLOB resource and giving it a name). A Pebble watchface or watchapp can handle resources of up to 96K, fortunately file with quotes was less, otherwise some kind of string compression would have to be implemented.

After that it’s a trivial matter to generate random position, retrieve quote from that position and display it on a text layer:

// determining number of quote (that will give us address of begining and end)
srand(time(NULL));
int number_of_quote = rand() % NO_OF_QUOTES;
  
//determining size of quote and allocating memory
int size_of_quote = aQuotePointers[number_of_quote + 1] - aQuotePointers[number_of_quote] - 1;
uint8_t *quote = malloc(size_of_quote);

//loading quote, displaying and freeing memory
ResHandle rh = resource_get_handle(RESOURCE_ID_FIREFLY_QUOTES);
resource_load_byte_range(rh, aQuotePointers[number_of_quote] + 1, quote, size_of_quote);
quote[size_of_quote] = 0; //null terminating string
text_layer_set_text(s_textlayer_quote, (char *)quote);

Lines 2-3 generate random index for the array of quote pointers
Lines 6-7 calculate size of the quote (based on position of current and next quote) and allocate memory for the quote
Lines 10-11 load range from the resource based on index and size
Lines 12-13 0-terminate the loaded range and display data on the text layer.

It’s all pretty straightforward and works like a magic and the result you can see in published watchface: Blue Sun Quotes.

Some useful links:

Next time I will describe how I handled situation when loaded quote is too long to display on a text layer

Root your Android device without flashing custom recovery

By , 02/15/2015 1:03 PM

HTC Rooted
It is fairly straightforward to root an Android phone using SDK platform tools (adb, fastboot), for example this is a very nice guide how to root HTC One M8. Basically you download SuperSU superuser manager to your device, download custom recovery image onto your computer and flash it to your device via command

fastboot flash recovery your_custom_recovery.img

then reboot into newly flashed recovery and flash the SuperSU. Boom, you’re done.

The problem with this approach, once you phone receives OTA (over the air) update (e.g. new version of Android) it needs original stock recovery to install it. If you have custom recovery (e.g. TWRP) – OTA update will fail. The solution is, when you root your phone, not to flash custom recovery, but just to reboot into it without flashing. Instead of above command, use

fastboot boot your_custom_recovery.img

This command will reboot your phone into custom recovery without flashing it. Then you can flash SuperSU and after reboot your phone will be rooted and original stock recovery remains.

You can even save the original stock recovery (after you rooted the phone) in case you do need to flash custom one. This way you can have a backup of stock recovery in case you need to flash it back to install OTA update. Below steps are for HTC One M8, but other devices will have similar approach:

Assuming that your phone is connected to PC, you have correct drivers installed and USB debugging mode enable.

run  "adb shell" command on your PC
"su" (watch your phone and grant permission if needed)
"dd if=/dev/block/mmcblk0p43 of=/sdcard/stock_recovery.img"

This will copy stock recovery of your HTC One M8 into file “stock_recovery.img” on the SD Card.

Credits go to this XDA thread

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