Get rid of findViewById in android. Single source of trust of layout files, without reduncency of codes.

Unix philosophy

Rule of Generation: Developers should avoid writing code by hand and instead write abstract high-level programs that generate code. This rule aims to reduce human errors and save time.

For this layout files: https://github.com/jozn/xml2java/tree/master/samples/BigApp/app/src/main/res/layout

The generated output is: https://github.com/jozn/xml2java/blob/master/samples/BigApp/app/src/main/java/com/example/big/bigapp/X.java

I demonstrate with an example for file activity_main.xml in layout directory:

<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"android:id="@+id/my_constraint_layout" > <TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Hello World!"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintLeft_toLeftOf="parent"app:layout_constraintRight_toRightOf="parent"app:layout_constraintTop_toTopOf="parent"android:id="@+id/my_text_view" /> </android.support.constraint.ConstraintLayout>

this tools will generate X.java:

packagecom.example.hello; importandroid.widget.*; importandroid.view.*; importandroid.webkit.WebView; importandroid.view.LayoutInflater; importandroid.content.Context; importandroid.support.constraint.ConstraintLayout;importcom.example.hello.R; publicclassX{publicstaticclassActivityMain{publicConstraintLayoutroot; publicConstraintLayoutmy_constraint_layout; publicTextViewmy_text_view; publicActivityMain(Contextcontext,ViewGroupparent){this(context,parent, R.layout.activity_main )} publicActivityMain(Contextcontext,ViewGroupparent, intlayout){root = (ConstraintLayout) LayoutInflater.from(context).inflate(layout,parent ,false); my_constraint_layout = (ConstraintLayout) root.findViewById( R.id.my_constraint_layout); my_text_view = (TextView) root.findViewById( R.id.my_text_view)} publicActivityMain(Contextcontext){this(context ,null)} publicActivityMain(ViewGroupparent){this(parent.getContext() ,parent)} publicstaticclassIDS{publicstaticintLAYOUT = R.layout.activity_main; publicstaticintmy_constraint_layout = R.id.my_constraint_layout; publicstaticintmy_text_view = R.id.my_text_view} } }

Then in your activates and fragments you can use this code:

packagecom.example.hello; importandroid.os.Bundle; importandroid.support.annotation.Nullable; importandroid.support.v7.app.AppCompatActivity; publicclassActivityextendsAppCompatActivity{X.ActivityMainx; @OverrideprotectedvoidonCreate(@NullableBundlesavedInstanceState){super.onCreate(savedInstanceState); x = newX.ActivityMain(getApplicationContext()); x.my_text_view.setText("Hi There!"); setContentView(x.root)} }

for every layout *.xml file at layout this tool will add an static class in X.java, every time that projects gets build this tool will sync all layouts with X class.

You must install Golang, then in command line:

go get github.com/jozn/xml2java

then in app gradle file add this:

taskxml2javaTask(type: Exec){commandLine'xml2java' , "com.example.hello"//your app package name } build.dependsOnxml2javaTaskandroid{preBuild.dependsOnxml2javaTask }

Use xml2java -h :

Usage: xml2java [--app_dir APP_DIR] [--xml_dir XML_DIR] [--out_dir OUT_DIR] [--out_class_name OUT_CLASS_NAME] PACKAGE Positional arguments: PACKAGE app package name (ex: com.example.hello) Options: --app_dir APP_DIR, -a APP_DIR android application project app path (default: current directory) --xml_dir XML_DIR, -x XML_DIR app xml layout directory (default example 'src/main/res/layout') --out_dir OUT_DIR, -o OUT_DIR directory to flush generated output (default example 'src/main/java/com/example/hello') --out_class_name OUT_CLASS_NAME, -n OUT_CLASS_NAME class name of generated output (default X) --help, -h display this help and exit 

The day that i build this tool, android databinding was not available. I build the main codes blocks of this tool in one night, after getting tired of waiting to new builds pushed to device and then crashed because of common error of cannot find id. this tool will obsolete this error and reduce a lot of boilerplate codes

This tool has near zero learning curve and zero redundant codes. The only single source of trust is just files at `/layout/*.xml'. Android databinding has learning curve and makes you to write logic code in xml files, something that is adapted from angluarjs. butterknife has a lot of redundancy of codes.

I build this tool mainly for my project, but later i decided to open source this, maybe in future i write this tool in java.

See this real world file X.java output to make a scence of what this tool produce to make devloer life easy (output of old version) : X.java