Emulator: Process finished with exit code 1 You opened AVD Manager in Android Studio and tried to start an AVD, you got “Emulator: Process finished with exit code 1”. Following are the steps to debug this Find out the name of the emulator. Click the down arrow 🔽 which is to the right of play arrow ▶️, to find out the name of the AVD. Let’s say the name is “Nexus_5X_API_28_x86”. ...
Die with me is a chat app which can be used only when the phone’s battery is below 5%. Here is a fun way to use the app without draining your phone’s battery. Connect the phone via ADB or start Android emulator and fake the battery level to 4%. Bash 1 2 sudo pip3 install adb-enhanced adbe battery level 4 # Set battery level to 4% And now, you can use the app. After playing with the app, reset the battery level with, ...
Sh 1 2 #!/usr/bin/env bash set -euo pipefail The first statement is a Mac, GNU/Linux, and BSD portable way of finding the location of the bash interpreter. The second statement combines ...
Ultimate guide to setting up and maintaining CI of your dotfiles
Update: As of Mar 2022, I recommend everyone to use GitHub Actions I maintain a somewhat popular Android developer tool ( adb-enhanced). The tool is written in Python, supporting both Python 2 and 3. Testing the tool requires both Python runtime as well a running Android emulator. I, initially, used Travis CI for setting up continuous testing of this tool. Later, I felt that Travis CI was too slow and when I came across Circle CI, I decided to give it a try. As of now, both Travis and Circle CI are used for testing. Here is what I learned from my experience.
Lectures Introduction Creating a Digital currency Bitcoin Overview Bitcoin Blockchain Bitcoin Mining Bitcoin Miner interactions and Game Theory Cryptocurrencies: Community, Economics, and Politics Alternative Consensus Wallet & Anonymity Anonymity on Blockchain Altcoins Ethereum Ethereum Ethereum Governance Bitcoin Side-chains (guest talk) Bitcoin Payment channel Guest talk on Legal by Ben Lawsky - does not seem worthy of transcribing Advanced Topics - Quantum Computing, Threshold Signatures, and storing secret state on public chains Advanced Topics - Smart property, publicly verifiable randomness, and prediction markets Guest talk by Adam Ludwin (CEO, chain.com) - does not seem worthy of transcribing The notes are based on the 2016 version of the course CS251 ...
Lecture 19: Advanced Topics Topic 1: Smart Property Manage ownership of some property like stocks on the blockchain. Colored coins allow arbitrary properties on Smart Contract. Similar to Namecoin, there cannot be a light node/SPV for this. Another example is rental, car’s ownership goes from Alice to Carol in a 2-of-2 transaction from Alice to Carol and locked transaction to return the car’s possession after a fixed time. One still has to trust the car’s hardware and manufacturer. ...
Lecture 18: Advanced Topics Three topics are chosen by students (another three for the next lecture) Topic 1: Quantum Computing An electron has two states top and bottom spins, represented as |1> and |0>. An electron is in a superposition of those two states with wave functions Ψ0 and Ψ1, so, the combined wave function is Ψ = Ψ0. |0> + Ψ1. |1> with |Ψ0|2 + Ψ12 = 1. |Ψ0|2 is the proability of seeing state |0> and Ψ12 is the probability of seeing state |1> respectively. Thus, Ψ = [Ψ0, Ψ1] is the overall state matrix. The state evolves using a 2X2 Hamiltonian matrix H, such that, second-degree norm won’t change, || H.V || = || V ||. This ensures |Ψ0|2 + Ψ12 = 1 always holds. ...
Lecture 16: Bitcoin payment channel Visa ~ 10, 000 transactions per second Bitcoin ~ 3 transactions per second => 60 GB of blockchain data per year Waiting for 6 blocks ~ 60 mins is a huge wait for Bitcoin. Therefore, tipping or having an ongoing channel of payments on the blockchain is hard. Payment channels help with that. Funding channel - unidirectional payment channels Alice is planning to pay Bob. ...
Lecture 15: Bitcoin guest talk (Greg Maxwell & Pieter Wuille - Blockstream) on sidechains Forking does not advance Bitcoin since forks suffer from economic acceptance. UTXO model UTXO model is less intuitive, more private, and smaller persistent storage footprint. UTXO implicitly prevents a replay attack. Ethereum carries nonce around even for empty accounts to prevent replay attacks. Validation not computation Bitcoin addresses are a 160-bit hash of the public key since the public key is unusually long (512-bit). Bitcoin payments can be made to scripts. These scripts are not for computation but spendability conditions. Rather than scripts, a hash of the script is added to the blockchain as a privacy improvement. 10% of Bitcoins are stored using P2SH scripts. MAST is meant to make transactions even smaller. One does not need a Turing-complete language since one only needs to verify and not compute on the blockchain. ...