问题
Is it possible to create an Android shape object with stroke on only certain sides?
Eg I have:
<stroke
android:width=\"3dip\"
android:color=\"#000000\"
android:dashWidth=\"10dip\"
android:dashGap=\"6dip\" />
Which is similar to this CSS:
border: 3px dashed black;
How can I set the stroke on just one side? This is how I would do it in CSS:
border-left: 3px dashed black;
How do you do this in Android XML?
回答1:
I achieved a good solution with this one:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This is the line -->
<item android:top="-1dp" android:right="-1dp" android:left="-1dp">
<shape>
<solid android:color="@android:color/transparent" />
<stroke android:width="1dp" android:color="#ffffff" />
</shape>
</item>
</layer-list>
This works well in case you need a transparent background but still an open stroke color (In my case I only needed a bottom line). If you need a background color you can add a solid shape color as in Maragues answer.
EDIT 1
Sometimes, for High Density devices, using low dip values may end in very thin or invisible strokes or distances. This may happen to you also when setting ListView dividers.
The simplest workaround is to use a distance of 1px instead of 1dp. This will make the line always visible at all densities. The best solution would be to create dimension resources for each density, to get the best size for each device.
Edit 2
Fun, but I tried to use this 6 years later and I can't get a good result on Lollipop devices.
Probably the current solution is to use 9-patch. Android should have made an easy solution for this problem after all this time.
回答2:
I solved this by using a list-layer, combining two shapes, one of which with height 1dp placed at the bottom
optionscreen_bottomrectangle.xml:
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This is the line -->
<item>
<shape>
<solid android:color="#535353" />
</shape>
</item>
<!-- This is the main color -->
<item android:bottom="1dp">
<shape>
<solid android:color="#252525" />
</shape>
</item>
</layer-list>
Then, in the layout/main.xml file
<TextView
android:id="@+id/bottom_rectangle"
android:background="@drawable/optionscreen_bottomrectangle"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_below="@id/table_options"
android:layout_above="@id/exit_bar"/>
Which fills the gap between table_options and exit_bar with a background and just before exit_bar prints a 1dp line. This did the trick for me, I hope it helps someone else.
Answer edited to place layers in the correct order. Thx Alex!
回答3:
I know this question was posted long ago, so the answer will not be used by the person who posted this question, but it may still help others.
<?xml version="1.0" encoding="UTF-8"?>
<!-- inset is used to remove border from top, it can remove border from any other side-->
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:insetTop="-2dp"
>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/rectangle">
<stroke android:width="1dp" android:color="#b7b7b7" />
<corners android:bottomRightRadius="5dp" android:bottomLeftRadius="5dp"/>
<solid android:color="#454444"/>
</shape>
</inset>
Use the inset tag and give a negative value for the side border you want to remove.
The possible values are:
android:insetTop="-1dp"
android:insetBottom="-1dp"
android:insetLeft="-1dp"
android:insetRight="-1dp"
回答4:
Another take on the other responses using padding instead. This little snipplet makes a border on top and bottom.
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This is the line -->
<item>
<shape>
<padding android:left="0dp" android:top="1dp" android:right="0dp" android:bottom="1dp"/>
<solid android:color="#898989" />
</shape>
</item>
<!-- This is the main color -->
<item>
<shape>
<solid android:color="#ffffff" />
</shape>
</item>
</layer-list>
回答5:
@Maragues's answer is backwards, as layer-list drawables draw from top to bottom (meaning the last item in the list is drawn on top):
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This is the line -->
<item>
<shape>
<solid android:color="#535353" />
</shape>
</item>
<!-- This is the main color -->
<item android:bottom="1dp">
<shape>
<solid android:color="#252525" />
</shape>
</item>
</layer-list>
This will effectively fill the shape with the line color, then draw the background color on top of it, leaving the last 1dp clear for the line color to show through.
回答6:
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="#BBBBBB" />
<solid android:color="@android:color/transparent" />
</shape>
</item>
<item android:bottom="2dp" >
<shape android:shape="rectangle" >
<stroke android:width="2dp"
android:color="@color/main_background_color" />
<solid android:color="@android:color/transparent" />
</shape>
</item>
回答7:
I've used following code.
<?xml version="1.0" encoding="UTF-8"?>
<!-- inset is used to remove border from top, it can remove border from any other side-->
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:insetTop="-2dp" android:insetLeft="-2dp" android:insetRight="-2dp"
>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/rectangle">
<stroke android:width="1dp" android:color="@color/colorPrimary" />
<solid android:color="#0000"/>
<padding android:left="2dp" android:top="2dp" android:bottom="2dp" android:right="2dp"/>
</shape>
</inset>
来源：https://stackoverflow.com/questions/2422120/open-sided-android-stroke