How can I change Phonegap Android app target-densitydpi dynamically?
Question
I'm developing an android app using Phonegap. I finished developing it on a 320px * 480px viewport dimensions. In order for the app to work on all screen sizes I used target-densitydpi=low-dpi in the viewport metatag but I found a problem in testing the app on Samsung S4 device. The problem was that the full screen images are not displayed in a very low quality although they are high.
I googled this problem and found that in order for the images to show on Samsung S4 in the same quality I should change target-densitydpi=low-dpi to target-densitydpi=device-dpi and this solved the problem but I found that I have to redesign the whole app to support all the screen sizes.
I'm asking is there a way to change the target-densitydpi dynamically using Javascript so I can make it equals device-dpi when the user open the full-screen image then return it back to low=dpi when he close the full-screen images?
I tried to put the images in a separate html file with target-densitydpi=device-dpi and make a link using tag to the new html file but the transition was too slow (takes about 5 seconds to open).
Any suggestions?
1 answers
solution1
0 2014-01-27 18:23:04
You can create your viewport using JavaScript before the page has loaded.
The following knowledge base article is an example of how to do this (to support BlackBerry 10 smartphones): http://supportforums.blackberry.com/t5/Web-and-WebWorks-Development/How-to-set-up-the-viewport-for-a-BlackBerry-WebWorks-application/ta-p/1943807
You can extend this example to address your requirements like this:
<head>
<script>
var meta = document.createElement("meta");
meta.setAttribute('name','viewport');
if (isS4) {
meta.setAttribute('content','target-densitydpi=device-dpi');
} else {
meta.setAttribute('content','target-densitydpi=low-dpi');
}
document.getElementsByTagName('head')[0].appendChild(meta);
</script>
</head>
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