Android布局缩放

Question

If you set your target SDK version in the Android manifest file to "3", then your layout on large-screen devices will be just a scaled up version of what it is on small-screen devices. Once you set the target SDK to a higher SDK, you can create separate layouts for each screen density, which provides a much better user experience.

However , my layout is mainly made up of images, that are high enough resolution that they display just fine on all screen sizes, even when scaled up, because they're big enough that they don't need to be stretched. Now, it would be much easier for me to just create a small-screen layout and have it scaled up, because it would still look nice on large screens. Is there any way I can get that effect without going back to API level 3?

Answer 1

You can use weight parameter.
“weight” is a term that's used to specify how much of the screen a particular view should occupy if there's any room left after it's drawn.

Simply make a LinearLayout and place two TextViews within it as such:

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="small"
    android:layout_weight="0.2"
    android:background="#123" />
 <TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="0.8"
    android:text="huge"
    android:background="#456"
 />
</LinearLayout>

You will notice how views occupy space accordingly. You can create any layout you want for smaller screen and specify weight attribute and every thing will be adjusted beautifully

Answer 2

Just don't specify a layout for larger screens. By default it uses the same one for all screens unless a more specific layout is available. If you're using match_parent for the width and height and the images to scaleType="fitCenter" or "centerCrop" -- things like that, it should fill whatever screen size that it is run on.

Answer 3

Dont'f forget making your app compaible with tablets. You must add

<supports-screens
    android:anyDensity="true"
    android:largeScreens="true"
    android:normalScreens="true"
    android:smallScreens="true"
    android:xlargeScreens="true" />

in your app manifest.

Answer 4

Hm. I thought Android already did this as long as you aren't using something like AbsoluteLayout. There's a few tricks that can help with the transition. Not entirely sure what the question is asking, but I'll give it a shot. Does API level 3 scale with aspect ratio or something?

I found that most of the UI ugliness going from phone to tablet deals with width. There's logic you can put in to fix the width at a certain res. Otherwise, the layout looks and acts fine. There other tricks like having assets sized using different dimens.xml, and having different sets of dimens.xml for different screen sizes and densities.

You don't have to have every single dimension in each version. You just have to have the base version of each value set, and you can set the different dimension in the other files.

Answer 5

Only way to resize images through different screen size is to use nine patch. Here is more resource on that subject : http://developer.android.com/tools/help/draw9patch.html

I believe this is only thing that you can do is in layout use relative width/height (weight) and images formatted in ninepath.