João Rocha’s Post

I’m happy to share that I’m starting a new position as Android Developer at ZONE SOFT!

Ever used Pythagoras in the real world? I recently did to build a color comparison API! Think of a color hex code (#FF0115) as a point in 3D space (X=FF, Y=01, Z=15) So you can calc how close colors are based on the distance of the points And the distance between the two points can be calculated using Pitagora's theorem! This inspired a Proof-of-Concept API that finds the closest color to a chosen hex code. Imagine using this concept to recommend makeup based on your skin tone in a photo! Link of the API in the comments #go #golang #gin

Are you creating an NFC feature? The APDUs can help you APDU (Application protocol data unit) is the communication format between NFC applications defined by ISO 7816-4. An APDU is a byte array, with each segment representing either an instruction or data. There are two types: Command APDU and response APDU. The reader sends a command APDU to the card in the format: CLA | INS | P1 | P2 | Lc | DATA | Le CLA - Indicates the type of command INS - Instruction code, e.g, "select", "write data" P1 and P2 - Instruction parameters for the command Lc - The number of bytes of the DATA DATA - Data sent from the reader to the card Le - Maximum size in bytes expected in the response And the card sends the Response APDU to the reader in the format: DATA | SW1 | SW2 DATA - Data sent from the card to the reader SW1 and SW2 - Command process status Example: Command APDU: CLA | INS | P1 | P2 | Lc | DATA | Le 90 | 04 | 00 | 00 | 06 | 1A 2B 3C 4D 5E 6F | 00 90 - Indicating a proprietary command 04 - Custom instruction for specific action 00 00 - No specific parameters 06 - There are 6 bytes of data in the DATA field 1A 2B 3C 4D 5E 6F - Hexadecimal values representing data 00 - No expected response length specified Response APDU: DATA | SW1 | SW2 1F 2E 3D 4C 5B 6A | 90 | 00 1F 2E 3D 4C 5B 6A - Hexadecimal values representing response data 90 00 - Indicating a successful command execution Have you applied this standard to some features? I used it to create an NFC payment system that works offline Please, share your experiences in the comments #Android #NFC #Payment

This is one of my favorite features of Jetpack Compose The Preview allows me to see all the different states of a composable at the same time This is a great time safer! #android #compose #UI #jetpackcompose

10 math concepts that you're probably using on developing without even thinking about it: 1. Boolean algebra: Is used to represent and manipulate logical values. For example, you can use Boolean algebra to write code that checks whether a variable is true or false or to perform logical operations such as AND, OR, and NOT. 2. Numeral systems: Are used to represent numbers on a computer. For example, the binary numeral system is used to represent numbers in computers because it is easy for computers to understand. 3. Floating points: Computers have limited space to store data, so instead of working with exact numbers in operations, they work with precision (32 BIT for single precision and 64 BIT for double precision) That is why 0.1+0.2 = 0.30000000000000004 in languages like Python and JS. It is called floating points because there is no fixed number of digits before or after the decimal point, allowing a trade-off between range and precision. 4. Logarithms: Are used to perform a variety of operations, such as calculating the base-10 logarithm of a number or raising a number to a power. Logarithms are used in a variety of programming tasks, such as calculating the time complexity of an algorithm or implementing a search algorithm. 5. Set theory: Is used to represent collections of objects. Sets are used, for example, to implement data structures such as hash tables and sets or perform operations such as union, intersection, and difference. 6. Combinatorics: Is used to count the number of possible arrangements of objects. Combinatorics is used in a variety of programming tasks, such as generating random numbers or implementing algorithms for sorting and searching. 7. Graph theory: Is used to represent networks of objects, like algorithms for routing and scheduling, or the Linkedin connections network. 8. Complexity theory: Is used to study the efficiency of algorithms. It is important for designing efficient algorithms for a variety of tasks, such as sorting and searching. 9. Statistics: Is used in a variety of programming tasks, such as implementing machine learning algorithms or performing data analysis. 10. Linear algebra: Is used to represent and manipulate vectors and matrices, that are used in tasks like implementing graphics algorithms or performing data analysis. What other concepts do you know? I found these and other examples in this funny video https://lnkd.in/dZjgXY4r

Standalone vs. non-standalone Wear OS apps: Which is right for you? Standalone Wear OS apps are fully independent applications that can run on a smartwatch without needing to be connected to a phone. This means that users can access all of the app's features, even if they don't have their phone with them. Non-standalone Wear OS apps, on the other hand, rely on a companion app on the user's phone. These apps typically have limited functionality when used on their own, but they can offer a more seamless experience when used in conjunction with a phone. When to use standalone Wear OS apps: - If you want to create an app that can be used without a phone, such as a fitness tracker or a music player. - If you want to create an app that can access data from sensors on the smartwatch, such as the heart rate sensor or the GPS. - If you want to create an app that can interact with other devices, such as smart home devices or wearables. When to use non-standalone Wear OS apps: - If you want to create an app that needs to access data from the phone, such as the user's contacts or calendar. - If you want to create an app that needs to use the phone's internet connection. - If you want to create an app that needs to use the phone's processing power. Read more: 5 design principles to create useful and engaging Wear OS apps by Google https://lnkd.in/dQy666wJ Reference: https://lnkd.in/dwXMe-Dz