CODEWITHSUNDEEP
androidandroid-vectordrawableandroid-appcompat
Solace
Solace

Reputation: 9020

How to use VectorDrawableCompat from the AppCompat library?

I initially wrote this SSCCE with a minsdkversion of 21 (Lollipop), and it worked fine. But my need is to use a VectorDrawableCompat in pre-lollipop. In the SSCCE, there is an ImageView in the XML layout, in which the source of the image is a vector graphic defined in res/drawable/ directory.

Initially, when minsdkversion was set to 21 in manifest, I used android:src="@drawable/vector_circle" to set the vector graphic as the source of the image in ImageView. This worked fine.

Then I changed minsdkversion in manifest file to 11. I also changed ImageView's android:src="@drawable/vector_circle" attribute to app:srcCompat="@drawable/vector_circle" in XML layout. But I am getting

Unexpected namespace prefix "app" found for tag ImageView

on app:srcCompat="@drawable/vector_circle" line. How should I fix this?

SSCCE:

res/drawable/vector_circle.xml:

<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android" 
     android:width="465dp"
     android:height="420dp"
     android:viewportHeight="600"
     android:viewportWidth="600" >

    <group>

        <path android:strokeColor="#2196F3"
            android:strokeWidth="2"
            android:pathData="M150,10 L75,200 L225,200 Z" />

    </group>

</vector>

activity_main:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center" >

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/vector_circle" /><!-- app:srcCompat="@drawable/vector_circle" -->

</FrameLayout>

MainActivity.java:

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

EDIT:

I changed res/layout/activity_main.xml's ImageView element to

<ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/vector_circle"
        tools:ignore="MissingPrefix" />

I also added layout-v21/activity_main.xml to the res/ directory:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center" >

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/vector_circle" /><!-- app:srcCompat="@drawable/vector_circle" -->

</FrameLayout>

and added the xmlns:tools="http://schemas.android.com/tools" to FrameLayout element.

The pre-compilation error went away. But when I run the app on Lollipop device, the vector graphic is drawn perfectly fine, but if I run the app on a pre-lollipop device, the application does not fail, but the vector graphic is not drawn at all.

Upvotes: 1

Views: 3527

Answers (1)

Alex Newman
Alex Newman

Reputation: 1396

All you have to do to fix this is use the widget that can handle app:srcCompat and that is AppCompatImageView instead of ImageView.

Upvotes: 2

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