Relative Layout: Different behavior on Api < 11

问题

I don't know why, but layout is shown well on device with Api 11+, isn't for older.

This is xml:

    <LinearLayout
        android:id="@+id/workers_linearlayout"
        android:layout_width="50dp"
        android:layout_height="70dp"
        android:layout_weight="1" >

        <RelativeLayout
            android:id="@+id/workers_relative_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center" >

            <ImageView
                android:id="@+id/imageView1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:src="@drawable/workers_small" />

            <ImageView
                android:id="@+id/imageView3"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_centerInParent="true"
                android:scaleX="0.5"
                android:scaleY="0.5"
                android:src="@drawable/ic_cerchio_rosso"
                android:translationX="25dp"
                android:translationY="-20dp" />

            <TextView
                android:id="@+id/workers_number"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="9"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:translationX="25dp"
                android:translationY="-20dp" />
        </RelativeLayout>
    </LinearLayout>

This is result on API 11+:

This on API 10-:

I tried to fix it playing with layouts and I can obtain a quite good result, but never like the first one.

Can someone help me?

EDIT:

Photo on devices:

EDIT2

Triangle warning are:

• String "9" should use string resource
• ImageView1 and 3: missing content description attribute
• RelativeLayout or it's parent possibly useless
• Nested weights are bad for performance

By the way, nothing of these fixed solving my problem i think

回答1:

Ok. I fixed it. Playing with the layout and following NikkyD's suggestion about "center in parent" feature, I followed this policy:

It's not possible to use scale and translation properties because older Apis (maybe) don't recognize them. So, I deleted translation and scaling options and scaled image by setting a fixed height and width for IV3 (30dpx30dp). Now dimension is right, but if I call "align parent Top" with "align parent Right" for IV3 and TextView, their position is good, but TextView is not positioned at the center of IV3. Exactly like this:

For fixing it, I added a new relative layout inside "workersRelativeLayout" and I put inside it IV3 and TextView and set, for each one, "center in the parent" to TRUE. Then, I set for a new relative layout "align parent Top" and "align parent Right". This is the final result:

This is new xml layout:

            <LinearLayout
                android:id="@+id/workers_linearlayout"
                android:layout_width="50dp"
                android:layout_height="70dp"
                android:layout_weight="1" >

                <RelativeLayout
                    android:id="@+id/workers_relative_layout"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:gravity="center" >

                    <ImageView
                        android:id="@+id/imageView1"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_centerInParent="true"
                        android:src="@drawable/workers_small" />

                    <RelativeLayout
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignParentRight="true"
                        android:layout_alignParentTop="true" >

                        <ImageView
                            android:id="@+id/imageView3"
                            android:layout_width="30dp"
                            android:layout_height="30dp"
                            android:layout_centerInParent="true"
                            android:src="@drawable/ic_cerchio_rosso" />


                        <TextView
                            android:id="@+id/workers_number"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:layout_centerInParent="true"
                            android:text="9"
                            android:textAppearance="?android:attr/textAppearanceMedium" />

                    </RelativeLayout>
                </RelativeLayout>
            </LinearLayout>

Hope this helps someone :)

EDIT

Pay attention to parent width size. If you set weight's parent to 1, naturally size is dynamic according to display size. The image is positioned always at the center parent and relative Layout of IV3 and TextView will be always top|right. So if parent width size grows, the distance between image centered and new relative layout grows too, and can happen something like this:

回答2:

The first LinearLayout has a weight. If it has a weight, then it needs to have one dimension set to 0dp, that would be the dimension in which it is scaled by its weight.

All 3 elements of the Relative Layout have "centeredinparent" true. The parent is the RelLayout.

IV3 has a height of match_parent, so it will be stretched to the height of the rel-layout. I am pretty sure that this overrides your scale 0.5 options.

Im not that sure but id guess the rel-layout centeredinparent overrides the translation as well.

Layouts are VERY ugly with options. Some are considered superior to others and they dont take effect. I played around a fair bit of time with relative layouts and found out, that in my case i could only arrange them with "below" but never "above" because for some reason the above positioning would not work (not even in the eclipse preview!!) but there was absolutely nothing wrong with the xml.

So im guessing some of your options overrule the others and this comes to bear on more modern APIs as they might be even more restrictive (or more broken, its still android ;) )

来源：https://stackoverflow.com/questions/13048766/relative-layout-different-behavior-on-api-11