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AndroidスタジオでナビゲーションドロワーActivityを作成しました。ナビゲーションドロワーのxmlファイルにはナビゲーションビューがあり、メニューを参照します。しかし、私はナビゲーションビューがリストビューを参照するようにしたい。私はXMLでそれをやったが、私はそれが私のリストアイテムを作成するために参照するテキストIDがヌルオブジェクトで呼び出されると言うエラーを取得します。どのように私はこれを修正することができます？ナビゲーションビュー内にリストビューを追加
ここに私のlogcatです：
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:399)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:369)
at android.widget.AbsListView.obtainView(AbsListView.java:2346)
at android.widget.ListView.makeAndAddView(ListView.java:1876)
at android.widget.ListView.fillDown(ListView.java:702)
at android.widget.ListView.fillFromTop(ListView.java:763)
at android.widget.ListView.layoutChildren(ListView.java:1685)
at android.widget.AbsListView.onLayout(AbsListView.java:2148)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1221)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:2733)
at android.view.View.layout(View.java:16668)
at android.view.ViewGroup.layout(ViewGroup.java:5443)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2171)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1931)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6042)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:876)
at android.view.Choreographer.doCallbacks(Choreographer.java:688)
at android.view.Choreographer.doFrame(Choreographer.java:624)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:862)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5468)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Javaコード：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
...
View drawerLayout = (View) findViewById(R.id.nav_view);
ArrayList<String> counters = new ArrayList<>();
counters.add("Sayaç 1");
counters.add("Sayaç 2");
counters.add("Sayaç 3");
counters.add("Sayaç 4");
counters.add("Sayaç 5");
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, R.layout.activity_main, android.R.id.text1, counters);
ListView listView = (ListView) findViewById(R.id.list);
listView.setAdapter(arrayAdapter);
}
...
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// 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.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
あなたの心のヘッダビュー内の
ListViewを探しますか？しかし、きちんとした質問のために+1。 –