activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:app="http://schemas.android.com/apk/res-auto"
                xmlns:tools="http://schemas.android.com/tools"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:paddingBottom="@dimen/activity_vertical_margin"
                android:paddingLeft="@dimen/activity_horizontal_margin"
                android:paddingRight="@dimen/activity_horizontal_margin"
                android:paddingTop="@dimen/activity_vertical_margin"
                tools:context=".MainActivity">

    <codeguru.labelededittext.LabeledEditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="number"
        app:editWeight="7"
        app:hint="@string/hint"
        app:label="@string/label"
        app:labelWeight="3"/>

</RelativeLayout>

LabeledEditText.java

package codeguru.labelededittext;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

public class LabeledEditText extends LinearLayout {

    private TextView label;
    private EditText edit;

    public LabeledEditText(Context context) {
        this(context, null);
    }

    public LabeledEditText(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public LabeledEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        label = new TextView(context);
        edit = new EditText(context);

        TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.LabeledEditText,
                0, 0);
        int[] set = {android.R.attr.inputType};
        TypedArray b = context.getTheme().obtainStyledAttributes(attrs, set, 0, 0);

        try {
            int labelWeight = a.getInt(R.styleable.LabeledEditText_labelWeight, 0);
            int editWeight = a.getInt(R.styleable.LabeledEditText_editWeight, 0);
            int totalWeight = labelWeight + editWeight;

            ViewGroup.LayoutParams labelParams = new LinearLayout.LayoutParams(
                    0, LayoutParams.WRAP_CONTENT, (float)labelWeight / (float)totalWeight);
            label.setLayoutParams(labelParams);

            ViewGroup.LayoutParams editParams = new LinearLayout.LayoutParams(
                    0, LayoutParams.WRAP_CONTENT, (float)editWeight / (float)totalWeight);
            label.setLayoutParams(editParams);

            label.setText(a.getString(R.styleable.LabeledEditText_label));
            edit.setHint(a.getString(R.styleable.LabeledEditText_hint));
            edit.setInputType(b.getInt(0, 0));
        } finally {
            a.recycle();
        }

        this.addView(label);
        this.addView(edit);
    }

}