android TextView setting the background color dynamically doesn't work ?

A1.

    textView.setBackgroundColor(0xfff00000);

    <color name="solid_red">#fff00000</color> 

    textView.setBackgroundResource(R.color.solid_red);

      textview.setBackground(ContextCompat.getColor(this,R.color.yourcolor));

if you are in fragment use below code

      textview.setBackground(ContextCompat.getColor(getActivity(),R.color.yourcolor));

if your ain recyclerview adapter use below code

     textview.setBackground(ContextCompat.getColor(context,R.color.yourcolor));

Here are the steps to do it correctly:

First of all, declare an instance of TextView in your MainActivity.java as follows:
```
TextView mTextView;
```
Set some text DYNAMICALLY(if you want) as follows:
```
mTextView.setText("some_text");
```
Now, to set the background color, you need to define your own color in the res->values->colors.xml file as follows:
```
<resources>
    <color name="my_color">#000000</color>
</resources>
```
You can now use "my_color" color in your java file to set the background dynamically as follows:
```
mTextView.setBackgroundResource(R.color.my_color);
```