Android - 用 xml 制作箭头形状

Question

I want to make a button for my shape like this one

Is there a way to do this with xml ? Like setting some points, in my case I have 5..

Answer 1

What you need is to create a shape xml file in your project's drawable-xxx folder and then use this shape as background for a button.

Here is the shape file called arrow_shape.xml :

<?xml version="1.0" encoding="UTF-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

<!-- Colored rectangle-->
<item>
    <shape android:shape="rectangle">
        <size 
            android:width="100dp"
            android:height="40dp" />
        <solid android:color="#5EB888" />
        <corners android:radius="0dp"/>
    </shape>
</item>

<!-- This rectangle for the top arrow edge -->
<!-- Its color should be the same as the layout's background -->
<item
    android:top="-40dp"
    android:bottom="65dp"
    android:right="-30dp">
    <rotate
        android:fromDegrees="45">
        <shape android:shape="rectangle">
            <solid android:color="#ffffff" />
        </shape>
    </rotate>
</item>

<!-- This rectangle for the lower arrow edge -->
<!-- Its color should be the same as the layout's background -->
<item
    android:top="65dp"
    android:bottom="-40dp"
    android:right="-30dp">
    <rotate
        android:fromDegrees="-45">
        <shape android:shape="rectangle">
            <solid android:color="#ffffff" />
        </shape>
    </rotate>
</item>

</layer-list>

Then use it as button's background, for example

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/arrow_shape"/>

Here is the screenshot:

More info on Layer-List you can find here .

EDIT:

Keep in mind though that I used certain values for the shape's width and height. If you change those you might need to change the values of the top, bottom and right attributes . So, in that case consider using different values in your project's values directory.

Answer 2

<?xml version="1.0" encoding="UTF-8"?>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item android:width="50dp" android:height="10dp" android:right="6dp">
        <shape>
            <solid android:color="@android:color/holo_green_dark"/>
            <corners
                android:bottomLeftRadius="2dp"
                android:topLeftRadius="2dp"/>
        </shape>
    </item>

    <item android:width="7dp" android:height="7dp"
        android:left="50dp">
        <rotate android:fromDegrees="45"
            android:pivotX="0"
            android:pivotY="0">
            <shape>
                <solid android:color="@android:color/holo_green_dark"/>
            </shape>
        </rotate>
    </item>

</layer-list>

Answer 3

With the Material Components library you can just use the standard MaterialButton defining the shapeAppearanceOverlay attribute:

Something like:

  <com.google.android.material.button.MaterialButton
      app:shapeAppearanceOverlay="@style/ShapeAppearanceOverlay.Button.Triangle"
      ...      />

And in your style define:

  <style name="ShapeAppearanceOverlay.Button.Triangle" parent="">
    <item name="cornerFamily">rounded</item>
    <item name="cornerSizeTopLeft">0dp</item>
    <item name="cornerSizeBottomLeft">0dp</item>

    <item name="cornerFamilyTopRight">cut</item>
    <item name="cornerFamilyBottomRight">cut</item>
    <item name="cornerSizeTopRight">50%</item>
    <item name="cornerSizeBottomRight">50%</item>
  </style>