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Trying to set opacity (alpha) for a view in android

Anurag Sharma 1911 13-Jan-2016
I am using a  button :
<Button 
     android:text="Submit" 
     android:id="@+id/Button01" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content">
</Button>
In my onCreate() event, I am calling Button01 like this:

setContentView(R.layout.main);
View Button01 = this.findViewById(R.id.Button01);
Button01.setOnClickListener(this);
There is a background in the application, and I want to set an opacity on this submit button. How can I set an opacity for this view? Is it something that I can set on the java side, or can I set in the main.xml file?

On the java side I tried Button01.mutate().SetAlpha(100), but it gave me an error
android android  android styles 
Updated on 27-Jun-2023
Anurag Sharma

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2 Answers

Aryan Kumar

Aryan Kumar

27-Jun-2023

Sure, here is how to set opacity for a view in Android:

Code snippet

import android.content.Context;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the view from the layout.
        View view = findViewById(R.id.view);

        // Set the opacity of the view.
        float opacity = 0.5f;
        view.setAlpha(opacity);
    }
}

In this code, we first get the view from the layout using the findViewById() method. Then, we set the opacity of the view using the setAlpha() method. The setAlpha() method takes a float value as input, which represents the opacity of the view. A value of 1.0f represents fully opaque, while a value of 0.0f represents fully transparent.

In this example, we are setting the opacity of the view to 0.5f, which means that the view will be half transparent.

 

Anonymous User

Anonymous User

13-Jan-2016
Hi Anurag,

You just need to extend TextView and override onSetAlpha:

import android.content.Context;
import android.util.AttributeSet;
import android.widget.TextView;
public class AlphaTextView extends TextView {
  public AlphaTextView(Context context) {
    super(context);
  }
  public AlphaTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }
  public AlphaTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }
  @Override
  public boolean onSetAlpha(int alpha) {
    setTextColor(getTextColors().withAlpha(alpha));
    setHintTextColor(getHintTextColors().withAlpha(alpha));
    setLinkTextColor(getLinkTextColors().withAlpha(alpha));
    return true;
  }
}
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