Last year, I presented a short tutorial on displaying web pages from inside your App Inventor apps. Now, here is a some what improved version that prompts for a web address URL, checks to see if http:// has been entered, and if not, prepends http:// to the front of the address. Then the web page is displayed.
The Designer View
There is not much to the user interface – a text box to enter the web URL and a button to display the web page. The page then appears below the button, and the content may be scrolled on the screen.
To create this user interface, drag a horizontal layout onto the screen and then add a label for the “Web page URL” prompt, followed by a text box for the data entry. Then add the Display web page button.
From the User Interface section of the Palette, at the left of the Designer screen, drag and drop a WebViewer component on to the design area.
The WebViewer is not a full Internet browser – it is a component that displays the specified web page only. The WebViewer does not support standard browser features, such as saving web page content nor does it provide a history of the web pages visited.
The Blocks Code
The entire app is implemented in the btnDisplayPage button event handler.
The contains text block checks to see if the entered web address contains “http://”, and if it does not contain “http://” then “http://” is inserted at the beginning of the web address string.
The page is displayed on screen where you placed the Web component (in the Designer view). That’s all there is to displaying a web page!
Key Features Shown
- Checking the user input text for the presence or absence of “http://”
- Calling the WebViewer component to display the selected web page
Note – due to the very short app in this demo, no source code has been uploaded.
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how to prevent it to display WEB PAGE NOT AVAILABLE
Not sure where this error message is produced. However, you might try this and see if this will help catch an error.
Add a Screen1.ErrorOccurred block to your code.
When bad errors occur that would stop your program, control will pass to this block. Here you can display the error message and error code number, and optionally ignore or try to fix the error.
Again, I don’t know for sure where and how the “Web page not available” is processed. This is just an idea to try.
Ed