CODEWITHSUNDEEP
javaandroidlistviewcastingonclick
MR Mido
MR Mido

Reputation: 1678

Crash when clicking on list item.

I am running the following code where:

@Override
    protected void onListItemClick(ListView listView, View view, int position,
            long id) {
        String item = (String) getListAdapter().getItem(position);
        Toast.makeText(this, item + " selected", Toast.LENGTH_LONG).show();
        Art art = (Art) getListAdapter().getItem(position);
        /*Intent intent = new Intent(this,X.class);
        intent.putExtra("art", art);
        this.startActivity(intent);*/
    }

My Art Class goes like this:

import java.io.Serializable;
import java.util.List;

import com.google.gson.annotations.SerializedName;

public class Art implements Serializable{

    private static final long serialVersionUID = 8359220892008313080L;

    @SerializedName("body")
    private String body;
    @SerializedName("title")
    private String title;
    @SerializedName("images")
    private List<Images> images;


    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public List<Images> getImages() {
        return images ;
    }

    public void setImages(List<Images> images) {
        this.images = images;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("***** Art  *****\n");
        sb.append("BODY=" + getBody() + "\n");
        sb.append("TITLE=" + getTitle() + "\n");
        sb.append("IMAGES=" + getImages() + "\n");
        sb.append("*****************************");

        return sb.toString();
    }

}

This is my log and it crashes at this particular line: Art art = (Art)getListAdapter().getItem(position);

E/AndroidRuntime(912): FATAL EXCEPTION: main
E/AndroidRuntime(912): java.lang.ClassCastException: java.lang.String cannot be cast to com.Art
E/AndroidRuntime(912):  at com.ArtListActivity.onListItemClick(ArtListActivity.java:118)
E/AndroidRuntime(912):  at android.app.ListActivity$2.onItemClick(ListActivity.java:319)

Any ideas/help as of why it's happening and a possible fix would be greatly appreciated, thanks for reading.

Upvotes: 0

Views: 68

Answers (3)

John Zoetebier
John Zoetebier

Reputation: 49

A class cast like: Child child = new Child();
Parent parent = (Parent) child;

will work if Parent is a super class of Child.

As class Art is not a super class of class type String the cast will fail.

Example below :

public class CastExample {

public static void main(String[] args) {

    Child child = new Child();      
    Parent parent = (Parent) child;

    System.out.println(parent.whoami());
    // Output: I am a Parent

}

private static class Parent {

    public String whoami() {
        return "I am a Parent";
    }
}

private static class Child extends Parent {

    public String whoami() {
        return "I am a Child";
    }
}

}

Upvotes: 0

Nasir
Nasir

Reputation: 2122

You cant cast the items to both String and Art. In your case the adapter has a list of Strings thats why it throws a ClassCastException.

Upvotes: 1

Steve Kuo
Steve Kuo

Reputation: 63054

Art art = (Art) getListAdapter().getItem(position);

getItem is returning a String and you are casting it to an Art. Your list adapter is holding strings and not Arts.

Upvotes: 1

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