-1
nullではない、私はそれがオンラインでない場合は活動の一部を隠し、ネットワークが利用可能なレイアウトである場合に表示したい奇妙なNullPointerExceptionがケーシングれサービスも、ビューが
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:background="@color/gray"
android:layout_height="match_parent"
tools:context=".MainActivity">
<RelativeLayout
android:visibility="gone"
android:id="@+id/online"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/message_rv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/chat_input_view" />
<org.slabs.fc.chatapp.utils.ChatTextInputView
android:id="@+id/chat_input_view"
app:actionMenu="@menu/input_actions"
android:layout_width="match_parent"
android:layout_alignParentBottom="true"
android:layout_height="wrap_content" />
</RelativeLayout>
<FrameLayout
android:id="@+id/not_online"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ImageView
android:src="@drawable/sad_cloud"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_gravity="center"
android:layout_marginBottom="80dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="No network"
android:layout_marginTop="50dp"
android:layout_gravity="center|center"
android:textStyle="bold"
android:textSize="30dp" />
</FrameLayout>
</RelativeLayout>
Serviceクラスは
ですpublic class ConnectionService extends Service {
// Constant
public static String TAG_ACTIVITY_NAME = "activity_name";
private int interval;
private String activity_name;
private Timer mTimer = null;
ConnectionServiceCallback mConnectionServiceCallback;
@Override
public IBinder onBind(Intent intent) {
return null;
}
public interface ConnectionServiceCallback {
void hasInternetConnection();
void hasNoInternetConnection();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e("SERVICE", "Started...");
interval = 10;
activity_name = intent.getStringExtra(TAG_ACTIVITY_NAME);
try {
Log.e("ACTIVITY_NAME", "Is " + activity_name);
mConnectionServiceCallback = (ConnectionServiceCallback) Class.forName(activity_name).newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
mTimer = new Timer();
mTimer.scheduleAtFixedRate(new CheckForConnection(), 0, interval * 1000);
return super.onStartCommand(intent, flags, startId);
}
class CheckForConnection extends TimerTask {
@Override
public void run() {
isOnline();
}
}
@Override
public void onDestroy() {
mTimer.cancel();
super.onDestroy();
Log.e("SERVICE", "Destroyed...");
}
public boolean isOnline() {
Log.e("SERVICE", "isOnline...");
ConnectivityManager cm =
(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()){
mConnectionServiceCallback.hasInternetConnection();
Log.e("SERVICE", "isOnline is TRUE...");
return true;
} else {
mConnectionServiceCallback.hasNoInternetConnection();
Log.e("SERVICE", "isOnline is FALSE...");
return false;
}
}
}
MainActivityは、私は、スタックトレース
0123を取得public class MainActivity extends AppCompatActivity implements ConnectionService.ConnectionServiceCallback{
Intent intentServeice = null;
private FrameLayout mNotOnline;
private RelativeLayout mOnline;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNotOnline = (FrameLayout) findViewById(R.id.not_online); // mNotOnline is initialized
mOnline = (RelativeLayout) findViewById(R.id.online); // mOnline is initialized
intentServeice = new Intent(this, ConnectionService.class);
intentServeice.putExtra(ConnectionService.TAG_ACTIVITY_NAME, MainActivity.this.getClass().getName());
startService(intentServeice);
}
// Callback methods of ConnectionService.ConnectionServiceCallback interface
@Override
public void hasInternetConnection() {
mOnline.setVisibility(View.VISIBLE); // Line number 433 of MainActivity getting NPE
mNotOnline.setVisibility(View.GONE); //
}
@Override
public void hasNoInternetConnection() {
}
}
です
03-16 11:49:08.602 28449-28527/ve.we.re.app E/AndroidRuntime: FATAL EXCEPTION: Timer-0
Process: ve.we.re.app, PID: 28449
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RelativeLayout.setVisibility(int)' on a null object reference
at ve.we.re.app.MainActivity.hasInternetConnection(MainActivity.java:433)
at ve.we.re.app.service.ConnectionService.isOnline(ConnectionService.java:116)
at ve.we.re.app.service.ConnectionService$CheckForConnection.run(ConnectionService.java:71)
at java.util.Timer$TimerImpl.run(Timer.java:284)
どのように私はこの問題に
を使用してみてくださいそのような 'Activity'をインスタンス化し、正しく動作させるようにします。さらに、 'newInstance（）'メソッド名は、そのインスタンスがすでに実行中のインスタンスと同じではないという手掛かりになるはずです。 –
OKですが、すべての解決策 –
oncreateの 'mOnline.setVisibility（View.VISIBLE）'をテストしてください –