DaveAlden DaveAlden - 4 months ago 72
Android Question

Scaling a Phonegap app for different Android screen sizes/densities?

I have a Phonegap app designed to run on Android phones and tablets. The scale of text and images looks fine on a phone, but too small on a 7” tablet.

Is there a way to set the scale for different screen sizes/densities that works for a Phonegap-based app? For a native Android app, multiple screen layouts (as mentioned in the android docs) would be a solution, but can this be used for a Phonegap-based app?

I could use CSS media queries to set font sizes based on screen size, but I want to scale the entire interface (including images) proportionally.

I tried using the CSS

zoom
property along with media queries to target specific screen sizes, but this screws up absolute positioning and interferes with the function of UI elements such as iScroll:

@media only screen and (min-device-width : 768px) {
body{
zoom: 125%;
}
}
@media only screen and (min-device-width : 1024px){
body{
zoom: 150%;
}
}


I also tried using the
targetdensity-dpi
meta viewport property - adjusting it to 120dpi makes the scale better on the 7” tablet, but too large on the phone. Since this is hard-coded in HTML rather than CSS, media queries can’t be used to vary it based on screen size:

<meta name="viewport"
content="width=device-width, initial-scale=1, targetdensity-dpi=120dpi">


Here's some screenshots from a testcase Phonegap app:


Answer

Just noticed I never answered this. The solution I used in the end was to use media queries to explicitly set font sizes and image assets based on the device size. Device testing showed this worked on all my target devices: iPhone, iPad, Android phones, Android 7" tablets, Android 10" tables. Hope it helps someone else.

For example:

/* Start with default styles for phone-sized devices */
    p,li{
        font-size: 0.9em;
    }
    h1{
        font-size: 1.2em;
    }
    button{
        width: 24px;
        height: 12px;
    }
    button.nav{
        background-image: url('img/phone/nav.png');
    }

@media only screen and (min-device-width : 768px) { /* 7" tablets */
    p, li{
        font-size: 1.3em !important;
    }
    h1{
        font-size: 1.6em !important;
    }
    button{
          width: 32px;
          height: 16px;
    }
    button.nav{
        background-image: url('img/tablet7/nav.png');
    }
}
@media only screen and (min-device-width : 1024px) { /* 10" tablets and iPad */
    p, li{
        font-size: 1.5em !important;
    }
    h1{
        font-size: 1.8em !important;
    }
    button{
        width: 48px;
        height: 24px;
    }
    button.nav{
        background-image: url('img/tablet10/nav.png');
    }
}