Tag: react native

React Native : fix ‘React/RCTDefines.h’ file not found

It is possible that after adding a new library in your React Native project (or after upgrading or adding some packages) you have the following error in XCode when you try to build:

<React/RCTDefines.h> file not found


'React/RCTDefines.h' file not found

This error means that the library is not correctly set up with your React Native project.
To fix this error, go to your library settings. You will have to modify the Header Search Path input in Build Settings :

Go to Libraries > YourLib.xcodeproj > Targets > Build Settings > Search “Header Search Path”

“Header Search Path” should be in the section “Search Paths”. I recommend to use the search input because there are a lot of fields.

In my case, the external library named “RNReactNativeMstuneMam.xcodeproj” was doing the problem, so I am opening the settings of the xcodeproj file of this project. It can be any other library with another name, but you will have to fix the xcodeproj file, following to the error path that you have.

Now, double click to Header Search Paths and add:

Add the entry ${SRCROOT}/../../../ios/Pods/Headers by double clicking

Set it to recursive:

set it to recursive

Now, you can clean and build again:

Clean project and build again

The error should not appear anymore as your library will find the Pods headers.

OnClick inside OnClick with React

While doing some test after putting the event OnClick in a DIV inside another DIV with the Onclick event, I was not able to trigger the OnClick event that was inside the other.

<div id="div1" style={{background: 'red'}} onClick={() => { 
  DIV 1
  <div id="div2" style={{background: 'green'}} onClick={() => { 
  console.log('you clicked div2');
    DIV 2
When we click on the DIV 2, it triggers the DIV 1 onClick event

If you click on the green div, and then, if you check the logs you see that the log is working, you triggered the event.
But, if you check your state, you will see that it’s div1, and not div2, but you clicked DIV 2.
Your click action has been propagate to the DIV 2.

How to solve the problem

In order to solve this problem, we will need a fix. So we can trigger both events.
The problem is that the click action is propagate to the the other div.
So, we need to check when you trigger the onClick action that the user clicked on the good one.
To do so, we can add the following instructions in the inner DIV:

if(event.target !== event.currentTarget) return;

Which will give:

<div id="div1" style={{background: 'red'}} onClick={(event) => { 
if(event.target !== event.currentTarget) return;
  DIV 1
  <div id="div2" style={{background: 'green'}} onClick={() => { 
  console.log('you clicked div2');
    DIV 2

With buttons inside a DIV with 3 levels DIV

If you have 3 levels of DIV and you want only the action of the button of the div the be triggered then you can use the following instruction in the end of the OnClick:

<div id="div3" style={{background: 'yellow'}} onClick={(event)=>{

stopPropagation will stop the click event and so the second OnClick event will not be triggered.

Hide and show blocks of content • React Native

While creating single page application or making dynamic forms, is it important to show or hide parts that we want the user to see or not.
We simply do this by adding variables in the constructor of the class :

this.level and this.status

Inside functions of the class we will modify the variables this.level and this.status.
We will display content by testing the value of those variables.
To do it, we will add { this.VARIABLE == VALUE && before the content we want and } at the end. For example :

How to get input text • React Native

In this article we will see how to get the user input text inside the <TextInput>, very simply.
In this example, we will be using a login page :

Login page

Add the reference for each TextInput at the top of your login class, inside the constructor :

Add references with React.createRef()

Then, put the ref tag inside the each TextInput.
Attribute this ref tag to each variable that have been referenced. Here is the example with this.logInput :

add the ref tag

Now you can get the value by using this.logInput.current._lastNativeText inside our code.