android:gravity fails on API 18+

问题

I have some TextViews on my app, I don't know why but the android:gravity attribute is not centering the text content where it should be on devices running the API 18+ (4.3+).

There is the code I use on my custom TextView, this is a child of RelativeLayout:

<com.package.custom.CustomTextFont
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/seekbar"
    android:layout_alignParentLeft="true"
    android:layout_alignTop="@+id/seekbar"
    android:layout_marginLeft="@dimen/margin_tiny_double"
    android:layout_toLeftOf="@+id/seekbar"
    android:gravity="center_vertical|left"
    android:paddingRight="@dimen/margin_tiny"
    android:text="@string/text1"
    android:textColor="@color/black"
    android:textSize="@dimen/size_text_normal" />

This code should take the edges of this TextView and align it to the top and bottom and put it to the Left of the SeekBar, this is working, but the TextView gets big, so with android:gravity I center the text to the center and left from it self. It works, but I don't know why, the text is not centered at center|left on devices running android 4.3 and 4.4. This issue can be reproduced on real devices and as well on the layout preview (Graphic layout) of Eclipse.

There is any changes made on API 18+ or on android:gravity that I'm missing?

PS: I'm targetting the API 19 on the project and on AndroidManifest.xml

PS2: My TextView is custom just to set an external font.tff

This is how it looks like on API 17-

This is how it looks like on API 18+

Thanks in advance!

= UPTADATE =

On my Manifest, I changed the android:targetSdkVersion to 17 instead of 19 and the problem disappeared, but this is a "trick", not a solution, what can I do since it could be an issue from the API ? And yes, I have the latest version of the API 18 and 19 (today, 01/30/2014).

回答1:

This appears to be a known issue in API 18+:

https://code.google.com/p/android/issues/detail?id=59368 https://code.google.com/p/android/issues/detail?id=59700

The problem seems to occur when a TextView is part of a scrollable container (e.g. ListView), making the view ignore the vertical gravity for some reason (some sources suggest this has to do with the TextView being the child of a RelativeLayout, though it's been my experience that this can happen even when no such layout is involved).

A possible workaround (albeit not a particularly elegant one), would be to wrap the TextView in a LinearLayout. You can then use "layout_gravity" on the TextView to center it inside the LinearLayout, instead of relying on "gravity" (just make sure to wrap_content so the text itself is properly centered).

E.g., in your example:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignBottom="@+id/seekbar"
    android:layout_alignParentLeft="true"
    android:layout_alignTop="@+id/seekbar"
    android:layout_toLeftOf="@+id/seekbar"
    android:layout_marginLeft="@dimen/margin_tiny_double" >

    <com.package.custom.CustomTextFont
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:gravity="left"
        android:paddingRight="@dimen/margin_tiny"
        android:text="@string/text1"
        android:textColor="@color/black"
        android:textSize="@dimen/size_text_normal" />

</LinearLayout>

This method does have the disadvantage of adding an otherwise-unnecessary level to your view hierarchy, but it currently seems to be the only way around this (other than reverting to an earlier API level).

Also see similar question at: Android sdk 18 TextView gravity doesn't work vertically

回答2:

Your textview height is "wrap_content", which means the height of the textview will be the same as the height of the text. If you change the background of the textview to black, it might be easier to see the bounds of the view. I'm guessing you'll find that the textview doesn't have as much height as you expect.

Try setting the height of the textview to match_parent. You can wrap the textview inside another view if needed and modify its height as appropriate.

来源：https://stackoverflow.com/questions/21444425/androidgravity-fails-on-api-18