Subclass of EditText isn't behaving like EditText

问题

I've written a subclass of EditText. Here is that subclass:

package com.package.foo;

import android.content.Context;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.widget.EditText;

public class FuturaEditText extends EditText{

    public FuturaEditText(Context context) {
        this(context, null, 0);
    }

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

    public FuturaEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        if(!isInEditMode()) {
            setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/futura.ttf"));
        }
    }

}

yet it doesn't behave like an EditText, but a TextView. In particular, the soft keyboard isn't rising on focus and it has no EditText formatting. Why?

回答1:

For completeness - from the source:

public EditText(Context context, AttributeSet attrs) {
       this(context, attrs, com.android.internal.R.attr.editTextStyle);
}

So, if the constructor is called with no default style, it defaults to editTextStyle

回答2:

This implementation, with each constructor calling the matched super constructor:

package com.package.foo;

import android.content.Context;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.widget.EditText;

public class FuturaEditText extends EditText{

    public FuturaEditText(Context context) {
        super(context);
        if(!isInEditMode()) {
            setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/futura.ttf"));
        }
    }

    public FuturaEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        if(!isInEditMode()) {
            setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/futura.ttf"));
        }
    }

    public FuturaEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        if(!isInEditMode()) {
            setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/futura.ttf"));
        }
    }

}

works. I can only assume that EditText(context, attrs, 0) is not the same as EditText(context, attrs).

回答3:

You should not invoke the super constructor completing the missing arguments, otherwise there's no way for a client to invoke a constructor with less than 3 arguments (i.e. super.(Context context, AttributeSet attrs)).

The second version is the correct one.

来源：https://stackoverflow.com/questions/16040376/subclass-of-edittext-isnt-behaving-like-edittext

标签

android

android-edittext

subclass