Android - drawable with rounded corners at the top only

问题

I had this drawable to have a rounded rectangle as a background:

<shape xmlns:android=\"http://schemas.android.com/apk/res/android\">
    <solid android:color=\"@color/white\" />
    <stroke android:width=\"1dp\" android:color=\"@color/light_gray\" />
    <padding android:left=\"10dp\" android:top=\"10dp\" android:right=\"10dp\" android:bottom=\"10dp\" />
    <corners android:radius=\"6dp\" />
</shape>

This is working fine, as expected.

Now, I want to change this to only round the top corners, so I change it to this:

<shape xmlns:android=\"http://schemas.android.com/apk/res/android\">
    <solid android:color=\"@color/white\" />
    <stroke android:width=\"1dp\" android:color=\"@color/light_gray\" />
    <padding android:left=\"10dp\" android:top=\"10dp\" android:right=\"10dp\" android:bottom=\"10dp\" />
    <corners android:topLeftRadius=\"6dp\" android:topRightRadius=\"6dp\"
             android:bottomLeftRadius=\"0dp\" android:bottomRightRadius=\"0dp\"/>
</shape>

But now none of the corners are rounded and I get a plain rectangle. What am I missing here?

回答1:

Try giving these values:

 <corners android:topLeftRadius="6dp" android:topRightRadius="6dp"
         android:bottomLeftRadius="0.1dp" android:bottomRightRadius="0.1dp"/>

Note that I have changed 0dp to 0.1dp.

EDIT: See Aleks G comment below for a cleaner version

回答2:

Try to do something like this:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:bottom="-20dp" android:left="-20dp">
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />

            <corners android:radius="20dp" />
        </shape>
    </item>
</layer-list>

It seems does not suitable to set different corner radius of rectangle. So you can use this hack.

回答3:

In my case below code

    <?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:top="10dp" android:bottom="-10dp"
        >

        <shape android:shape="rectangle">
            <solid android:color="@color/maincolor" />

            <corners
                android:topLeftRadius="10dp"
                android:topRightRadius="10dp"
                android:bottomLeftRadius="0dp"
                android:bottomRightRadius="0dp"
            />
        </shape>

    </item>
    </layer-list>

回答4:

Building upon busylee's answer, this is how you can make a drawable that only has one unrounded corner (top-left, in this example):

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />
            <!-- A numeric value is specified in "radius" for demonstrative purposes only,
                  it should be @dimen/val_name -->
            <corners android:radius="10dp" />
        </shape>
    </item>
    <!-- To keep the TOP-LEFT corner UNROUNDED set both OPPOSITE offsets (bottom+right): -->
    <item
        android:bottom="10dp"
        android:right="10dp">
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />
        </shape>
    </item>
</layer-list>

Please note that the above drawable is not shown correctly in the Android Studio preview (2.0.0p7). To preview it anyway, create another view and use this as android:background="@drawable/...".

回答5:

I tried your code and got a top rounded corner button. I gave the colors as @ffffff and stroke I gave #C0C0C0.

try

1. Giving android : bottomLeftRadius="0.1dp" instead of 0. if its not working
2. Check in what drawable and the emulator's resolution. I created a drawable folder under res and using it. (hdpi, mdpi ldpi) the folder you have this XML. this is my output.

回答6:

You may need read this https://developer.android.com/guide/topics/resources/drawable-resource.html#Shape

and below there is a Note.

Note Every corner must (initially) be provided a corner radius greater than 1, or else no corners are rounded. If you want specific corners to not be rounded, a work-around is to use android:radius to set a default corner radius greater than 1, but then override each and every corner with the values you really want, providing zero ("0dp") where you don't want rounded corners.

回答7:

Create roung_top_corners.xml on drawable and copy the below code

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
<corners
    android:topLeftRadius="22dp"
    android:topRightRadius="22dp"
    android:bottomLeftRadius="0dp"
    android:bottomRightRadius="0dp"
    />
<gradient
    android:angle="180"
    android:startColor="#1d2b32"
    android:centerColor="#465059"
    android:endColor="#687079"
    android:type="linear" />
<padding
    android:left="0dp"
    android:top="0dp"
    android:right="0dp"
    android:bottom="0dp"
    />
<size
    android:width="270dp"
    android:height="60dp"
    /></shape>

来源：https://stackoverflow.com/questions/8930555/android-drawable-with-rounded-corners-at-the-top-only