如何删除布局中的屏幕边界线？

Question

我的应用程序屏幕上有白色边框，如下所示：

当我更改背景颜色时，我注意到了这一行。

如何删除它？

这是我的代码。

TimeTableFragment.java

public class TimeTableFragment extends Fragment {

DBHelper dbHelper;
SQLiteDatabase db;
private static final String TAG = "TimeTableFragment";
private Context mContext;


@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.activity_time_table_fragment, container, false);

    return view;
}
...
}

TimeTableLayout.xml

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/back_gradi"
tools:context=".TimeTableFragment">


<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="352dp"
    android:layout_height="499dp"
    android:layout_marginStart="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginBottom="8dp"
    android:background="@drawable/table_back"
    android:stretchColumns="1"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView">

    <TableRow>

        <TextView

....

@ drawble / back_gradi.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android">
<gradient
    android:startColor="@color/back"
    android:endColor="#2a3350"
    android:angle="45"/>
</shape>

MainActivity.java

public class MainActivity extends AppCompatActivity {

private FragmentManager fragmentManager = getSupportFragmentManager();

private HomeFragment homeFragment = new HomeFragment();
private TimeTableFragment timeTableFragment = new TimeTableFragment();
private SettingFragment settingFragment = new SettingFragment();

Fragment active = homeFragment;


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

    fragmentManager.beginTransaction().add(R.id.main_container, timeTableFragment, "1").hide(timeTableFragment).commit();
    fragmentManager.beginTransaction().add(R.id.main_container, settingFragment, "3").hide(settingFragment).commit();
    fragmentManager.beginTransaction().add(R.id.main_container, homeFragment, "2").commit();

    BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.navigation_view);

    fragmentManager.beginTransaction().add(R.id.main_container,homeFragment);
    bottomNavigationView.setSelectedItemId(R.id.action_home);

    // 아이템 선택 될 시
    bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {

            switch (menuItem.getItemId()){
                case R.id.action_home:
                    fragmentManager.beginTransaction().hide(active).show(homeFragment).commit();
                    homeFragment.paint();
                    active = homeFragment;

                    return true;

                case R.id.action_timetable:
                    fragmentManager.beginTransaction().hide(active).show(timeTableFragment).commit();
                    timeTableFragment.sendData(getApplicationContext());
                    active = timeTableFragment;
                    return true;

                case R.id.action_setting:
                    fragmentManager.beginTransaction().hide(active).show(settingFragment).commit();
                    active = settingFragment;
                    return true;

            }
            return false;
        }
    });


  }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>


<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<include
    layout="@layout/content_main"
    android:layout_width="match_parent"
    android:layout_height="453dp"
    android:layout_above="@+id/navigation_view"
    android:layout_alignParentStart="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_alignParentEnd="true"
    android:layout_alignParentRight="true"
    android:layout_marginStart="0dp"
    android:layout_marginLeft="0dp"
    android:layout_marginTop="0dp"
    android:layout_marginEnd="0dp"
    android:layout_marginRight="0dp"
    android:layout_marginBottom="0dp" />


<android.support.design.widget.BottomNavigationView
    app:labelVisibilityMode="labeled"
    app:itemTextColor="@android:color/holo_blue_dark"
    app:itemIconTint="@android:color/holo_blue_dark"
    android:id="@+id/navigation_view"
    android:background="@color/back_nav"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    app:menu="@menu/bottom_navi"> 
</android.support.design.widget.BottomNavigationView>


</RelativeLayout>