Extending a EditText in Android. What am I doing wrong?

Question

So I\'m trying to get a grasp of using custom controls in Android. But my app crashes on trying to create the activity. Here\'s the code:

package com.myApp;
         


        

Answer 1

You will need to implement these constructors:

public class TestEditText extends EditText {
    public TestEditText(Context context) {
        super(context);
    }

    public TestEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public TestEditText(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public TestEditText(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }
}

for example try to do the following :

public TestEditText(Context context, AttributeSet attrs) {
    super(context, attrs);
    Log.i("attribute name at index 0", attrs.getAttributeName(0));
}

you will get the following in your logcat :

attribute name at index 0 = id 

so to deliver these XML attributes to the Super class (EditText) you have to override these constructors.

Hope that Helps.

Answer 2

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Typeface;
import android.os.Build;
import android.util.AttributeSet;




/**
 * Created by rohann on 14/07/2016.
 */
public class LightEditText extends android.widget.EditText{

    public LightEditText(Context context) {
        super(context);
        setFont();

    }

    public LightEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        setFont();
    }

    public LightEditText(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setFont();
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public LightEditText(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        setFont();
    }

    /**
     * This method is used to set the given font to the TextView.
     */
    private void setFont() {
        Typeface typeface = TypefaceCache.get(getContext().getAssets(), "fonts/Roboto-Light.ttf");
        setTypeface(typeface);
    }

    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
    }
}

Answer 3

You have to add this constructor for creating any custom View.

public MyEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
.....
}

instead of

public MyEditText(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }