Null Exception error while retrieving array of child views

Question

I have level1.xml which has relative layout and image view as child I want to retrieve those views to set their margins progrmatically here is my xml

  <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/Level1Layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="objectClick" 
            android:background="@drawable/hh_gmw_03">

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="593dp"
        android:layout_marginLeft="998dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image1"
        android:src="@drawable/hht3l01"/>

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="39dp"
        android:layout_marginLeft="20dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image1"
        android:src="@drawable/hht3l02" />

    <ImageView
        android:id="@+id/imageView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="153dp"
        android:layout_marginLeft="497dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image3"
        android:src="@drawable/hht3l03" />

    <ImageView
        android:id="@+id/imageView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="524dp"
        android:layout_marginLeft="998dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image4"
        android:src="@drawable/hht3l04" />

    <ImageView
        android:id="@+id/imageView5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="183dp"
        android:layout_marginLeft="715dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image5"
        android:src="@drawable/hht3l05" />

    <ImageView
        android:id="@+id/imageView6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="413dp"
        android:layout_marginLeft="557dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image6"
        android:src="@drawable/hht3l06" />

    <ImageView
        android:id="@+id/imageView7"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="53dp"
        android:layout_marginLeft="532dp" 
        android:onClick="objectClick" 
        android:contentDescription="Image1"
        android:tag="Image7"
        android:src="@drawable/hht3l07" />
</RelativeLayout>

and here is my ExampleActivity

public class ExampleActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ImageView[] Objects = (ImageView[]) getViewArrays(R.layout.level1);
    Log.d("Check","Objects" + Objects.toString());
}



public View[] getViewArrays(int resid)
{
    ViewGroup layout = (ViewGroup) this.findViewById(resid);

    View[] views = new View[layout.getChildCount()];

    for (int i = 0; i < layout.getChildCount(); i++) {
        views[i] = layout.getChildAt(i);
    }

    return views;
}

public int[] getViewIds(int resid)
{
    ViewGroup layout = (ViewGroup) this.findViewById(resid);

    int[] ids = new int[layout.getChildCount()];

    for (int i = 0; i < layout.getChildCount(); i++) {
        ids[i] = layout.getChildAt(i).getId();
    }

    return ids;
}

}

It is giving me null exception error at this line View[] views = new View[layout.getChildCount()]; ...... Why my layout is not found ?

e.perrot · Accepted Answer · 2012-02-29 19:20:33Z

1

Is your xml file main.xml? Then you should replace this line:

ImageView[] Objects = (ImageView[]) getViewArrays(R.layout.level1);

By this:

ImageView[] Objects = (ImageView[]) getViewArrays(R.id.Level1Layout);

The problem is that you give a layout xml file in parameter, that's why you have an exception: you have to give a view id.

answered Feb 29, 2012 at 19:20

e.perrot

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user1169079 · Accepted Answer · 2012-03-01 09:46:18Z

0

Found answer by myself .... I have remove that this.findviewbyid () ...instead only findviewbyID

But now it return Views and not imageview[] . It saying View[] can not be typecast to Imageview[]

answered Mar 1, 2012 at 9:46

user1169079

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