CollapsingToolbarLayout not showing Title

Remove this

@Override
public void setTitle(CharSequence title) {
    if (title != null && !title.toString().isEmpty()) {
        mTitle = title.toString();
        mCollapsingToolbarLayout.setTitle(mTitle);
    }
}

and add this on your OnCreate().

    mCollapsingToolbarLayout = (CollapsingToolbarLayout)findViewById(R.id.collapsing);
    mCollapsingToolbarLayout.setTitleEnabled(false);

    mToolbar.setTitle("title");

This disables the default title with collapsing behaviour and adds the static title to the toolbar.

For who searches for disabling the title just add

app:titleEnabled="false"

Then the title of the toolbar itself would appear so we will disable it with

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);

or with those line in the style xml

<item name="android:displayOptions">showHome|useLogo</item>
<item name="displayOptions">showHome|useLogo</item>

Searched too much to make this search summary, wish it helps.