Aaron He's blog

Aaron He's blog

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Using git filter-repo to rewrite commit history

git filter-repo is a neat tool to rewrite commit history. A recent use case required me to move an entire repository to another repository while preserving history. A simple git subtree would do the move, but one little problem is after the commit history moved over, the commit messages would

Updating Ghost

Every time I update Ghost, there is always some problems taking down the site. A lot of the times it's just because things like I forgot to update nodejs before updating Ghost CLI. Here I'm writing the steps down so next time I can follow them exactly, and hopefully they

Moshi Kotlin Gotchas

Moshi 1.5 added @Json annotation support for Kotlin classes. It's a great addition for Kotlin projects and has been working really well for me. I'd just like to share three tips when working with Moshi Kotlin. No generics support yet Resovling generics types is still working in progress. AutoValue

A little trick to add WebP "transparency" support on pre-4.2 devices

WebP is great, but transparency WebP is only supported natively on Android since 4.2.1. Even though everyone should have minSdk set to at least 19 by now, for apps that sill have a large amount of users on pre-4.2 devices, there's a little trick maybe apply to

Get rid of `get` prefix for Kotlin property getters

One of the nice things Kotlin provides is interoperability with Java. Existing Java code can just call Kotlin classes/methods as if they were Java classes/methods. However, when it comes to property getters, the equivalent Java method would have a get prefix. This is can be a little bit

Retrofit 2 dynamic header

In Retrofit 2, when we need to add additional headers, we would just add an implementation of the Interceptor. But sometimes, we only need to add a particular header for one API call, and the value is set dynamically at runtime. It's a bit tedious to add another interceptor just

Use JDK 8 to prevent OOM during Gradle builds

Recently, I've run into OutOfMemoryError: PermGen space issue when building Gradle projects, especially with Kotlin. A common way to fix that is to increase the heap size for Gradle JVM, like adding org.gradle.jvmargs=-XX:MaxPermSize=512m to grade.properties. Actually, there's another simple way to fix the issue

Cleanup when a subscriber unsubscribes

Often times, I need to clean up stuff after a subscriber unsubscribes. There's a handy methods just for that: Subscriptions.create(Action0). The parameter Action0 is a function passed in to do things after a subscriber unsubscribes. For example, if a callback is set on an instance when a subscriber

Enable ProGuard for Android Project

Lately we have to deal with Android 65k method limit, so enabling ProGuard to remove some unreferenced methods might be a good way to temporarily solve this problem. Enable ProGuard It's really easy to enable ProGuard. If using Maven, just add the following code in your pom file under Android