runtime ImageButton with PNG image with transparent background failure

Question

I would like to add every time I push ADD button (see the red circle) create a runtime ROW with 2 Edittext and 1 ImageButton, I use a PNG image, but when I try to create a transparent background the result is or a gray image or a white image (see the yellow arrow)...

When

this is the runtime code for add the ROW

ImgBtAdd.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                LayoutInflater layoutInflater = (LayoutInflater) appContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                final View addView = layoutInflater.inflate(R.layout.rrow_ing, null);

                AutoCompleteTextView et_ing = (AutoCompleteTextView) addView.findViewById(R.id.et_ingrediente);
                EditText et_qty = (EditText) addView.findViewById(R.id.et_qty);
                et_ing.setAdapter(adapter);
                //textOut.setText(et_ing.getText().toString());
                final ImageButton ImgBtClear = (ImageButton ) addView.findViewById(R.id.imgBt_clear);

                //ImgBtClear.setBackgroundColor(Color.TRANSPARENT); //don't work
                //ImgBtClear.setBackgroundResource(0);              //don't work

                ImgBtClear.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        ((LinearLayout)addView.getParent()).removeView(addView);
                        listAllAddView();
                    }
                });

                //ImgBtClear.setOnClickListener(thisListener);
                IngContainer.addView(addView);
                listAllAddView();
            }
        });

This is the XML for the ROW

<?xml version="1.0" encoding="utf-8"?>
<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="wrap_content">

        <android.support.design.widget.TextInputLayout
            android:id="@+id/input_name"
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:layout_toLeftOf="@+id/input_qty"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true">

            <AutoCompleteTextView
                android:id="@+id/et_ingrediente"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/txt_ingrediene"
                android:text=""
                android:inputType="text"
                app:errorEnabled="true"/>
        </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/input_qty"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/imgBt_clear"
        android:layout_toStartOf="@+id/imgBt_clear"
        >
        <android.support.design.widget.TextInputEditText
            android:id="@+id/et_qty"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/txt_quantita"
            android:text=""
            android:inputType="number|numberDecimal"
            android:layout_alignParentTop="true"
            android:layout_toRightOf="@+id/input_qty"
            android:layout_toEndOf="@+id/input_qty"/>
    </android.support.design.widget.TextInputLayout>

    <ImageButton
        android:id="@+id/imgBt_clear"
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/directory_up"
        android:scaleType="centerInside"
        tools:ignore="ContentDescription"
        android:focusable="false"
        android:layout_alignParentRight="true"
        android:baselineAlignBottom="true"
        android:layout_alignBottom="@+id/input_qty"

        android:background="#00000000" //don't work
        android:background="@null" //don't work
        android:background="@android:color/transparent" //don't work

        android:layout_alignParentTop="true"/>
</RelativeLayout>

I have tried different method:

android:background="#00000000" //don't work
android:background="@null" //don't work
android:background="@android:color/transparent" //don't work

if I use the android:background this is the result if I remothe the code the result is:

I used this code for the ADD button and works fine android:background="#00000000"

I compile with this parameter:

compileSdkVersion 25
    buildToolsVersion "23.0.3"
    defaultConfig {
        applicationId "com.bandweb.myviewrecipes"
        minSdkVersion 16
        targetSdkVersion 23

Answer 1

In your ImageView you must use android:src not app:srcCompat, So:

Change this:

app:srcCompat="@drawable/directory_up"

With this:

android:src="@drawable/directory_up"