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メモを書き込むためのアプリがあります。 MainActivityにTextViewがあります。ユーザーがメモを追加した後に非表示にしておき、ユーザーがすべてのメモを削除した後に表示するようにします。実際、メモを追加した後、TextViewは消えましたが、メモをすべて削除すると、別のアクティビティを入力してMainActivtiyに戻るまで、またはアプリケーションを閉じてから戻ってくるまで、TextViewは表示されません。RecyclerViewとTextView自体を更新した後にTextViewが表示されない
* MainActivity.java：
package com.twitter.i_droidi.notah;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.AppCompatDelegate;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import io.realm.OrderedRealmCollection;
import io.realm.Realm;
import io.realm.RealmChangeListener;
public class MainActivity extends AppCompatActivity {
private NotesAdapter adapter;
private Realm realm;
protected RecyclerView recyclerView;
private RealmChangeListener realmChangeListener;
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.realm = RealmController.with(this).getRealm();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
textView = (TextView) findViewById(R.id.textEmpty);
updateView();
setupRecycler();
realmChangeListener = new RealmChangeListener() {
@Override
public void onChange(Object element) {
RealmController.with(MainActivity.this).refresh();
}
};
setRealmAdapter(RealmController.with(this).getNotes());
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent createNote = new Intent(MainActivity.this, CreateNote.class);
startActivity(createNote);
}
});
}
public void setRealmAdapter(OrderedRealmCollection<Notes> notes)
{
RealmNotesAdapter realmNotesAdapter = new RealmNotesAdapter(this.getApplicationContext(), notes);
adapter.setRealmAdapter(realmNotesAdapter);
adapter.notifyDataSetChanged();
}
private void setupRecycler()
{
recyclerView.setHasFixedSize(true);
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new NotesAdapter(this);
recyclerView.setAdapter(adapter);
}
protected void updateView()
{
if(RealmController.with(MainActivity.this).hasNotes())
{
recyclerView.setVisibility(View.VISIBLE);
textView.setVisibility(View.GONE);
}
else
{
if(recyclerView != null)
{
recyclerView.setVisibility(View.GONE);
textView.setVisibility(View.VISIBLE);
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId())
{
case R.id.night_mode:
getDelegate().setLocalNightMode(AppCompatDelegate.MODE_NIGHT_YES);
recreate();
return true;
case R.id.about:
Intent intent = new Intent(MainActivity.this, About.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
}
* NotesAdapter.java：
package com.twitter.i_droidi.notah;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.support.v7.app.AlertDialog;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import io.realm.Realm;
import io.realm.RealmResults;
public class NotesAdapter extends RealmRecyclerViewAdapter<Notes> {
protected final Context context;
protected Realm realm;
public NotesAdapter(Context context)
{
this.context = context;
}
@Override
public NotesViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_view, parent, false);
return new NotesViewHolder(view);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
realm = RealmController.getInstance().getRealm();
final Notes note = getItem(position);
final NotesViewHolder myHolder = (NotesViewHolder) holder;
//myHolder.noteTitle.setText(note.getTitle());
myHolder.noteBody.setText(note.getBody());
myHolder.card.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final RealmResults<Notes> results = realm.where(Notes.class).findAll();
/*Notes note = results.get(position);
final String title = note.getTitle();*/
AlertDialog.Builder deleteDialog = new AlertDialog.Builder(context);
deleteDialog.setTitle(R.string.delete_note_title);
deleteDialog.setMessage(R.string.delete_note_msg);
deleteDialog.setIcon(android.R.drawable.ic_delete);
deleteDialog.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
realm.beginTransaction();
results.deleteFromRealm(position);
realm.commitTransaction();
MainActivity obj = new MainActivity();
obj.updateView();
notifyDataSetChanged();
Toast noteDeleted = Toast.makeText(context, R.string.note_deleted, Toast.LENGTH_SHORT);
noteDeleted.show();
}
});
deleteDialog.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// DO NOT DO ANYTHING.
}
});
deleteDialog.show();
return false;
}
});
myHolder.card.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context, ViewNote.class);
intent.putExtra("id", position);
context.startActivity(intent);
}
});
}
@Override
public int getItemCount() {
if(getRealmAdapter() != null)
{
return getRealmAdapter().getCount();
}
return 0;
}
private static class NotesViewHolder extends RecyclerView.ViewHolder
{
protected CardView card;
//protected TextView noteTitle;
protected TextView noteBody;
public NotesViewHolder(View view)
{
super(view);
card = (CardView) view.findViewById(R.id.card_view);
//noteTitle = (TextView) view.findViewById(R.id.note_title);
noteBody = (TextView) view.findViewById(R.id.note_body);
}
}
}
* activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
tools:context=".MainActivity">
<RelativeLayout
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:id="@+id/toolbar"
android:background="@color/colorPrimary"
android:elevation="6dp"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="@style/AppTheme.PopupOverlay" />
<FrameLayout
android:id="@+id/framemain"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@id/toolbar">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="2.5dp"
android:paddingRight="2.5dp"
android:adjustViewBounds="true" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_gravity="center"
android:text="Add some notes."
android:textSize="22sp"
android:textAppearance="?android:attr/textAppearanceLarge"
android:id="@+id/textEmpty" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="16dp"
android:clickable="true"
android:src="@android:drawable/ic_menu_add"
android:tag="bg_tint_accent_color_selector_lighter"
app:elevation="6dp"
app:pressedTranslationZ="12dp" />
</FrameLayout>
</RelativeLayout>
</android.support.design.widget.CoordinatorLayout>
私を助けるために誰かがここにありますか？ – Androider
うん。 'RealmController.with'を使うよう指示したチュートリアルに従わないでください。悪いチュートリアルです。 – EpicPandaForce