Problem with creating Compound Control in Android

I am learning to create a compound control in android. For starters i tried an edit text with an attached button to clear it.

The problem is even though i can see the compound control in the graphical view of the main.xml, there is an error message : "Custom view ClearableEditText is not using the 2- or 3-argument View constructors; XML attributes will not work" This is not visible in project explorer under errors only in the xml graphical view i am able to compile and run but get a force close.

XML : COMPOUND CONTROL clearable_edit_text.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
>
    <EditText android:id开发者_Python百科="@+id/editText"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
    />
    <Button android:id="@+id/clearButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="CLEAR"
    />
</LinearLayout>

CLASS

public class ClearableEditText extends LinearLayout 
{
    EditText et;
    Button btn;

    public ClearableEditText(Context context)
    {
        super(context);
        LayoutInflater li=(LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        li.inflate(R.layout.clearable_edit_text,this,true);

        et=(EditText)findViewById(R.id.editText);
        btn=(Button)findViewById(R.id.clearButton);

        hookupButton();
    }

    private void hookupButton()
    {
        btn.setOnClickListener(new Button.OnClickListener()
        {
            public void onClick(View v)
            {
                et.setText("");
            }
        });
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
>
    <com.commsware.android.merge.ClearableEditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
    />
    <com.commsware.android.merge.ClearableEditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
    />
</LinearLayout>

Your class extends LinearLayout but you never add any views to it. You need to call addView(...) and pass your inflated view as the parameter.

Also, to define your view in XML you need to override the 2 and 3 argument constructors for a LinearLayout. Add this to your code:

public ClearableEditText(Context context, AttributeSet attrs) {

    super( context, attrs );
}

public ClearableEditText(Context context, AttributeSet attrs, int defStyle) {

    super( context, attrs, defStyle );
}

To get all 3 constructors to use the same initialization code, move your code from the single argument constructor to the 3 argument constructor, then in the other 2 constructors call this(context, null, 0) and this(context, attrs, 0) respectively.