Android - Why is the TextView shown as having a height?

Question

I've got an odd problem here. Basically I have a TextView with no default set text. I would've expected it to have a height of 0 since it hsas no content but there seems to be a gap between the elements above and below it. If I set the height to 0 in the XML and then try and change it through Java code then it does not reset the height.

How do I set the height to be 0 if the content is blank but then allow it to be changed programmatically?

Here is the code that I have:

<TextView 
    android:gravity="center_horizontal|center_vertical"
    android:id="@+id/connectionStatus"
    android:layout_height="wrap_content"
    android:layout_width="fill_parent"
    android:textSize="18px"
    android:textStyle="bold">
</TextView>

and the Java code is this:

    private void getConnectionStatus()
{
    if (hasConnection() == true)
    {
        //do something
    }
    else
    {
        connectionStatus.setHeight(48);
        connectionStatus.setText("No Internet Access");
    }   
}

Why would you set the height to 0? Leave the height as `wrap_content` and just hide the view. — K-ballo, Nov 16 '11 at 23:03
edited the tags (removed 'connection' tag, and added 'view' and 'visibility' tags) — Vit Khudenko, Sep 20 '12 at 07:38

score 7 · Accepted Answer · answered Nov 16 '11 at 23:05

7

Use visibility "gone" inside of the xml layout. Then in the Java code call connectionStatus.setVisibility(View.VISIBLE);

answered Nov 16 '11 at 23:05

Vit Khudenko

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Agreed. Setting visibility is the right way to hide/show views. – dmon Nov 16 '11 at 23:06

score 2 · Answer 2 · edited Feb 10 '18 at 09:28

2

Components may still display themselves even if they don't have content. For example, the may display a border or their viewable area. In order to make it not show up at all you need to use setVisibility(View.GONE).

edited Feb 10 '18 at 09:28

Derlin

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answered Nov 16 '11 at 23:07

heneryville

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score 1 · Answer 3 · answered Sep 26 '17 at 07:05

I've often wondered if this behaviour is intuitive. If you want a TextView that has no height when the text is empty you can make one:

import android.content.Context;
import android.support.annotation.Nullable;
import android.text.TextUtils;
import android.util.AttributeSet;

public class NoHeightWhenEmptyTextView extends android.support.v7.widget.AppCompatTextView {

    public NoHeightWhenEmptyTextView(Context context) {
        super(context);
    }

    public NoHeightWhenEmptyTextView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public NoHeightWhenEmptyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int newHeightMeasureSpec = heightMeasureSpec;
        if (TextUtils.isEmpty(getText())) {
            newHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.EXACTLY);
        }
        super.onMeasure(widthMeasureSpec, newHeightMeasureSpec);
    }

    @Override
    public void setText(CharSequence text, BufferType type) {
        super.setText(text, type);
        // ConstraintLayout totally ignores the new measured height after non-empty text is set.
        // A second call to requestLayout appears to work around the problem :(
        requestLayout();
    }
}

Android - Why is the TextView shown as having a height?

3 Answers3