Class cast exception while getting a String from listview

Question

I am running the following code onItemClickListener of a ListView. But it shows ClassCastException when i put the string at position arg2 in a string s as:

String s= (String) arg0.getItemAtPosition(arg2);

Code snippet:

lv1.setOnItemClickListener(new OnItemClickListener() {

     @Override
     public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {
       String out;
       String s = (String) arg0.getItemAtPosition(arg2);
       //some code
     }
}

I am posting the stack trace also :

07-14 02:35:42.798: E/AndroidRuntime(412): FATAL EXCEPTION: main
07-14 02:35:42.798: E/AndroidRuntime(412): java.lang.ClassCastException: bitcream.whats.your.score.Rest
07-14 02:35:42.798: E/AndroidRuntime(412):  at bitcream.whats.your.score.Intermediate$1.onItemClick(Intermediate.java:55)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.widget.AdapterView.performItemClick(AdapterView.java:284)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.widget.ListView.performItemClick(ListView.java:3513)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.os.Handler.handleCallback(Handler.java:587)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.os.Handler.dispatchMessage(Handler.java:92)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.os.Looper.loop(Looper.java:123)
07-14 02:35:42.798: E/AndroidRuntime(412):  at android.app.ActivityThread.main(ActivityThread.java:3683)
07-14 02:35:42.798: E/AndroidRuntime(412):  at java.lang.reflect.Method.invokeNative(Native Method)
07-14 02:35:42.798: E/AndroidRuntime(412):  at java.lang.reflect.Method.invoke(Method.java:507)
07-14 02:35:42.798: E/AndroidRuntime(412):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
07-14 02:35:42.798: E/AndroidRuntime(412):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
07-14 02:35:42.798: E/AndroidRuntime(412):  at dalvik.system.NativeStart.main(Native Method)
07-14 02:35:45.468: I/Process(412): Sending signal. PID: 412 SIG: 9

Please suggest a fix.

The adapter code is :

public class Myadapter extends ArrayAdapter<Rest>{

    Context ctx;
    List<Rest> list;
    Rest r1;
    ImageView iv1;
    TextView tv1, tv2;
    public Myadapter(Context context, int textViewResourceId,
            List<Rest> objects) {
        super(context, textViewResourceId, objects);
        ctx = context;
        list = objects;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater lii = (LayoutInflater) ctx.getSystemService(ctx.LAYOUT_INFLATER_SERVICE);
        View row = lii.inflate(R.layout.li, null, false);
        tv1 = (TextView) row.findViewById(R.id.textView1);
        r1 = list.get(position);
        tv1.setText(r1.name);
        work();
        return row;
    }

The Rest class is as:

package bitcream.whats.your.score;

public class Rest {
    String name;
    public Rest(String name) {
        this.name = name;
    }
}

Does the statement arg0.getItemAtPosition(arg2) returns String? If not convert them to String first before storing them to String s. — jofftiquez
– jofftiquez, Commented Jul 14, 2014 at 3:40
post the Rest Class code. DO you have getter and setter's there. also post the adapter code and look at developer.android.com/reference/android/widget/… — Raghunandan
– Raghunandan, Commented Jul 14, 2014 at 3:46

Raghunandan · Accepted Answer · 2014-07-14 03:52:25Z

3

Your list is populated by Rest. public class Myadapter extends ArrayAdapter<Rest>{

public Object getItemAtPosition (int position)

Added in API level 1
Gets the data associated with the specified position in the list.

Parameters
position    Which data to get
Returns
The data associated with the specified position in the list

So this arg0.getItemAtPosition(arg2) does not return a String and you cast it to String leading to ClassCastException.

So in onItemClick

Rest rs = (Rest) arg0.getItemAtPosition(arg2);
String value= rs.name

answered Jul 14, 2014 at 3:52

Raghunandan

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Comments

Elliott Frisch · Accepted Answer · 2014-07-14 03:57:51Z

1

Your type isn't a String, but it could be any Object (because of the ? type, in this case it happened to be a bitcream.whats.your.score.Rest). I believe you want to use toString()

String s = arg0.getItemAtPosition(arg2).toString();

Edit

Based on your update, you should add toString() to Rest - something like,

public class Rest {
  String name;
  public Rest(String name) {
    this.name = name;
  }
  @Override
  public String toString() {
    return name;
  }
}

edited Jul 14, 2014 at 3:57

answered Jul 14, 2014 at 3:40

Elliott Frisch

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4 Comments

Shubhankar Over a year ago

arg0.getItemAtPosition(arg2) it itself return a String so if i cast it to String whats wrong in it the tostring() function also does the same i guess

Elliott Frisch Over a year ago

If this String s= (String) arg0.getItemAtPosition(arg2); gives you a ClassCastException then it is not a String.

Shubhankar Over a year ago

Gets the data associated with the specified position in the list. developer.android.com/reference/android/widget/…

Elliott Frisch Over a year ago

@Shubhankar Yes, and it returns an Object - not a String. public Object getItemAtPosition (int position)

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