Android studio 制約レイアウト ConstraintLayout

public
class
LayoutDisplayActivity 
extends
AppCompatActivity {
private
static
final
String TAG = LayoutDisplayActivity.
class
.getSimpleName();
static
final
String EXTRA_LAYOUT_ID = TAG + 
".layoutId"
; 
// Layout ID
@Override
protected
void
onCreate(
@Nullable
Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
setTitle(getIntent().getStringExtra(Intent.EXTRA_TITLE));
final
int
layoutId = getIntent().getIntExtra(EXTRA_LAYOUT_ID, 
0
);
setContentView(layoutId); 
// set page layout, reuse layout
}
}

public
class
MainActivity 
extends
AppCompatActivity {
@Override
protected
void
onCreate(Bundle savedInstanceState) {
super
.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView list = (ListView) findViewById(R.id.activity_main);
ArrayAdapter<String> adapter = 
new
ArrayAdapter<>(
this
,
android.R.layout.simple_list_item_1, LIST_ITEMS);
list.setAdapter(adapter);
list.setOnItemClickListener(
new
AdapterView.OnItemClickListener() {
@Override
public
void
onItemClick(AdapterView<? > adapterView, View view, 
int
i, 
long
l) {
// Reuse the display layout
Intent intent = 
new
Intent(MainActivity.
this
, LayoutDisplayActivity.
class
);
intent.putExtra(Intent.EXTRA_TITLE, LIST_ITEMS[i]); 
// Title
intent.putExtra(LayoutDisplayActivity.EXTRA_LAYOUT_ID, LAYOUT_IDS[i]); 
// Layout Id
startActivity(intent);
}
});