我已经尝试了一个月进行大量研究，将其转换为Fragment，因为我需要它用于我的导航菜单。基本上我是在创建一个应用程序。我使用我的MainActvity使用Fragment运行导航菜单。然后我将不得不使用这些类并将其作为Fragment运行，但有一次我不得不使用AppCompatActivity，因此我将其转换为Fragment，但遇到了Intent和其他变量的问题。
这是MainActivity
class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setSupportActionBar(toolbar)
val toggle = ActionBarDrawerToggle(
this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
drawer_layout.addDrawerListener(toggle)
toggle.syncState()
nav_view.setNavigationItemSelectedListener(this)
}
override fun onBackPressed() {
if (drawer_layout.isDrawerOpen(GravityCompat.START)) {
drawer_layout.closeDrawer(GravityCompat.START)
} else {
super.onBackPressed()
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
when (item.itemId) {
R.id.action_refresh -> return true
else -> return super.onOptionsItemSelected(item)
}
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
val fragmentManager = fragmentManager
// Handle navigation view item clicks here.
when (item.itemId) {
R.id.content_main -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
, MainContent())
.commit()
// Handle the camera action
}
R.id.nav_events -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Events())
.commit()
}
R.id.nav_map -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Map())
.commit()
}
R.id.nav_study -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Study())
.commit()
}
R.id.nav_avatar -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Avatar())
.commit()
}
R.id.nav_settings -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Settings())
.commit()
}
R.id.nav_faq -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,FAQ())
.commit()
}
R.id.nav_share -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,ShareCalendar())
.commit()
}
R.id.nav_send -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,SendEvent())
.commit()
}
R.id.nav_feedback -> {
fragmentManager.beginTransaction()
.replace(R.id.content_frame
,Feedback())
.commit()
}
}
drawer_layout.closeDrawer(GravityCompat.START)
return true
}
}
这是Events类
public class Events extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> {
private FloatingActionButton mAddEventButton;
private Toolbar mToolbar;
EventCursorAdapter mCursorAdapter;
EventDbHelper eventDbHelper = new EventDbHelper(getActivity());
ListView eventListView;
ProgressDialog prgDialog;
private static final int VEHICLE_LOADER = 0;
@Nullable
@Override
public ListView onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
eventListView = (ListView) inflater.inflate(R.layout.nav_events, container, false);
return eventListView;
mToolbar = (Toolbar) getView().findViewById(R.id.toolbar);
((AppCompatActivity)getActivity()).setSupportActionBar(mToolbar);
mToolbar.setTitle("Events");
eventListView = (ListView) getView().findViewById(R.id.list);
View emptyView = getView().findViewById(R.id.empty_view);
eventListView.setEmptyView(emptyView);
mCursorAdapter = new EventCursorAdapter(getActivity(), null);
eventListView.setAdapter(mCursorAdapter);
eventListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
Intent intent = new Intent(Events.this, AddEvent.class, null);
Uri currentVehicleUri = ContentUris.withAppendedId(EventContract.EventEntry.CONTENT_URI, id);
// Set the URI on the data field of the intent
intent.setData(currentVehicleUri);
startActivity(intent);
}
});
mAddEventButton = (FloatingActionButton) getView().findViewById(R.id.fab);
mAddEventButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(v.getContext(), AddEvent.class);
startActivity(intent);
}
});
getLoaderManager().initLoader(VEHICLE_LOADER, null, this);
}
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {
EventContract.EventEntry._ID,
EventContract.EventEntry.KEY_TITLE,
EventContract.EventEntry.KEY_DATE,
EventContract.EventEntry.KEY_TIME,
EventContract.EventEntry.KEY_REPEAT,
EventContract.EventEntry.KEY_REPEAT_NO,
EventContract.EventEntry.KEY_REPEAT_TYPE,
EventContract.EventEntry.KEY_ACTIVE
};
return new CursorLoader(getActivity(), // Parent activity context
EventContract.EventEntry.CONTENT_URI, // Provider content URI to query
projection, // Columns to include in the resulting Cursor
null, // No selection clause
null, // No selection arguments
null); // Default sort order
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
mCursorAdapter.swapCursor(cursor);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
mCursorAdapter.swapCursor(null);
}
}
我需要帮助。我正在学习如何编码。 我得到的错误是：
我带走了＃34; null＆＃34; from line＆＃34; Intent intent = new Intent（Events.this，AddEvent.class，null）;＆＃34;在Events类中出现此错误：
Error:(63, 33) error: no suitable constructor found for Intent(Events,Class<AddEvent>) constructor Intent.Intent(String,Uri) is not applicable (argument mismatch; Events cannot be converted to String) constructor Intent.Intent(Context,Class<?>) is not applicable (argument mismatch; Events cannot be converted to Context)