Android Programming creating own View

Question

At the moment I'm trying to create a own view. Now I found the usefull tutorial on developer.android.net. I followed the instroduction, but I have some trouble to use the view.

First, my folder structur

cView.java

package company.firstactivity.customViews;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;

public class cView extends View{
    public cView(Context context, AttributeSet attrs){
        super(context,attrs);
    }
}

cViewAttributes.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="cView">
        <attr name="showText" format="boolean" />
    </declare-styleable>
</resources>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="company.firstactivity.MainActivity">

</RelativeLayout>

My problem is the namespace to use the view. What is the namespace? Can anyone help me?

Thanks in advance!

You mean you want to know how to include your view at xml level? — andrea.petreri
– andrea.petreri, Commented Jan 26, 2016 at 19:45
@PearsonArtPhoto Press on the link and then the point: Define Custom Attributes. -> Instead of belonging to the schemas.android.com/apk/res/android namespace, they belong to schemas.android.com/apk/res/[your package name]. — MyNewName
– MyNewName, Commented Jan 26, 2016 at 19:45
@thetonrifles correct. I want to use the custom view in the xml (with the attribute showText. — MyNewName
– MyNewName, Commented Jan 26, 2016 at 19:46

Mike · Accepted Answer · 2016-01-26 19:55:55Z

4

The namespace in the xml can be anything but it should always have the value http://schemas.android.com/apk/res-auto. Please refer to my_custom_namespace in the following example to understand how you use it:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:my_custom_namespace="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="company.firstactivity.MainActivity">

    <company.firstactivity.customViews.cView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        my_custom_namespace:showText="true"/>
</RelativeLayout>

You can change the my_custom_namespace to app or whatever you'd like to have.

On the other hand, if you'd like to use the custom attributes in the java code of your custom view you can read this value this way:

public cView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initView(context, attrs);
}

public cView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    initView(context, attrs);
}

private void initView(Context context, AttributeSet attrs) {
    if (attrs != null) {
        TypedArray styledAttrs = context.obtainStyledAttributes(attrs, R.styleable.cView);
        boolean shouldShowText = styledAttrs.getBoolean(R.styleable.cView_showText, false);
        styledAttrs.recycle();
    }
}

edited Jan 26, 2016 at 19:55

answered Jan 26, 2016 at 19:48

Mike

4,5904 gold badges35 silver badges48 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Mike Over a year ago

Let me know if it works or if you have other questions regarding this. If not, you can accept the answer so others can take it as a reference.

MyNewName Over a year ago

yeha, your solution worked well. I accepted it. Thanks!

PearsonArtPhoto · Accepted Answer · 2016-01-26 19:48:10Z

1

To use a custom view in XML, you have to use the fully specified name. This is the combination of the package with the class name. So yours would be company.firstactivity.customViews.cView

answered Jan 26, 2016 at 19:48

PearsonArtPhoto

39.9k17 gold badges116 silver badges147 bronze badges

Comments

vorujack · Accepted Answer · 2016-01-26 19:52:02Z

1

you can move content of cViewAttributes.xml to file attire.xml in res/values

then in your layout xml you can declare xmlns

xmlns:app="http://schemas.android.com/apk/res-auto"

and then you can use

app:showText="false"

answered Jan 26, 2016 at 19:52

vorujack

1,9601 gold badge18 silver badges25 bronze badges

Collectives™ on Stack Overflow

Android Programming creating own View

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related