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All trademarks belong to their respective company owners 91 pages, published on May Theory Now we will update our container component. This component will handle the state and pass the props to the presentational component. Container component is only used for handling state.
All functionality related to view styling etc. Example If we want to use example from the last chapter we need to remove the Text element from the render function since this element is used for presenting text to the users. This should be inside the presentational component.
Let us review the code in the example given below. We will import the PresentationalComponent and pass it to the render function. After we import the PresentationalComponent and pass it to the render function, we need to pass the props. Now, we will be able to access this inside the presentational component. Theory Presentational components should be used only for presenting view to the users.
These components do not have state. They receive all data and functions as props. The best practice is to use as much presentational components as possible. Example As we mentioned in our previous chapter, we are using the EC6 function syntax for presentational components. The only difference is that we refactored our code to the container and the presentational component. You can run the app and see the text as in the following screenshot. If you click on text, it will be removed from the screen.
You can use the style property to add the styles inline. However, this is not the best practice because it can be hard to read the code. In this chapter, we will use the Stylesheet for styling. Container Component In this section, we will simplify our container component from our previous chapter. At the bottom of the file, we will create our stylesheet and assign it to the styles constant.
We will use the same code that we used in our React Native - Styling chapter. We will only change the PresentationalComponent. The following table shows the possible options. Property Values Description Used to specify if elements will be aligned flexDirection 'column', 'row' vertically or horizontally. Each container uses different properties.
We will import List in our Home component and show it on screen. This will iterate over an array of items, and render each one.
The Home component will import and render inputs. After defining the initial state, we will create the handleEmail and the handlePassword functions. These functions are used for updating state.
The login function will just alert the current value of the state. We will also add some other properties to text inputs to disable auto capitalisation, remove the bottom border on Android devices and set a placeholder. When we click on the Submit button, text from inputs will be shown inside the dialog box.
We will again create ScrollViewExample. We will create it in state. Adding Image Let us create a new folder img inside the src folder. We will add our image myImage. We will show images on the home screen.
The app will load only the image necessary for particular screen density. The following will be the names of the image inside the img folder. It is recommended to define the width and the height for network images. We can also check the console to see the response. We call them 'touchable' because they offer built in animations and we can use the onPress prop for handling touch event.
Facebook offers the Button component, which can be used as a generic button. Consider the following example to understand the same. Touchable Opacity This element will change the opacity of an element when touched.
Usually, this component is not used much. Home Component We will use Home screen like in other chapters. Let us now import the Animations component and render it on screen. This property is used for styling an element inside PresentationalAnimationComponent. We will also create two functions: expandElement and collapseElement. These functions will update values from the state.
The first one will use the spring preset animation while the second one will have the linear preset. We will pass these as props too. The Expand and the Collapse buttons call the expandElement and collapseElement functions.
Example In this example, we will dynamically change the width and the height of the box. Since the Home component will be the same, we will only change the Animations component. Value 50 this. React Native — Debugging React Native React native offers a couple of methods that help in debugging your code. Step 1 — Install Router To begin with, we need to install the Router.
We will use the React Native Router Flux in this chapter. You can run the following command in terminal, from the project folder.
For Android, you can do the same in index. It will return Router with several scenes. Each scene will need key, component and title. Router uses the key property to switch between scenes, component will be rendered on screen and the title will be shown in the navigation bar.
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