Question

I’m new on Android development, so I’m developing an simple application that hides a textview pressing some button, so in the java code in the method for the OnClick event for the button I set the textview as invisible, I used:

textView.setVisibility(1);

because 1 is the value for “invisible” described in the android reference, but it does not work, so after I used

textView.setVisibility(View.INVISIBLE);

and it works, so When is the “1” value used? and Why is View.INVISIBLE = 4 instead of 1 as the android reference says?

In the android reference I can see that the value Invisible for attribute android:visibility is defined as 1

Answer 1

This is a good question, I checked the Android source code (frameworks/base/core/java/android/view/View.java)

case com.android.internal.R.styleable.View_visibility:
    final int visibility = a.getInt(attr, 0);
    if (visibility != 0) {
          viewFlagValues |= VISIBILITY_FLAGS[visibility]; //here is the key to your question
          viewFlagMasks |= VISIBILITY_MASK;
    }
    break;

Here is the content of VISIBILITY_FLAGS:

private static final int[] VISIBILITY_FLAGS = {VISIBLE, INVISIBLE, GONE};

The value of the array elements are actually the value shown in Android Reference

/**
     * This view is visible.
     * Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int VISIBLE = 0x00000000;

    /**
     * This view is invisible, but it still takes up space for layout purposes.
     * Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int INVISIBLE = 0x00000004;

    /**
     * This view is invisible, and it doesn't take any space for layout
     * purposes. Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int GONE = 0x00000008;

So even if you use the android:invisible in the manifest file, Android framework will finally call setVisibility(…) with the value 4.