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私のアプリは起動時に常にクラッシュします。これはAndroidモニターのエラーです。java.lang.RuntimeException：アクティビティを開始できません
01-30 23:42:55.281 5767-5767/silverbeach.meintieralter E/AndroidRuntime: FATAL EXCEPTION: main
Process: silverbeach.meintieralter, PID: 5767
java.lang.RuntimeException: Unable to start activity ComponentInfo{silverbeach.meintieralter/silverbeach.meintieralter.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3254)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3350)
at android.app.ActivityThread.access$1100(ActivityThread.java:222)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1795)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at silverbeach.meintieralter.FragmentOne.onCreate(FragmentOne.java:36)
at android.app.Fragment.performCreate(Fragment.java:2242)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1163)
at android.app.BackStackRecord.run(BackStackRecord.java:793)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1552)
at android.app.FragmentController.execPendingActions(FragmentController.java:325)
at android.app.Activity.performStart(Activity.java:6914)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3217)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3350)
at android.app.ActivityThread.access$1100(ActivityThread.java:222)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1795)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
01-30 23:42:55.401 5767-5767/silverbeach.meintieralter I/Process: Sending signal. PID: 5767 SIG: 9
コード
package silverbeach.meintieralter;
import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.view.View.OnClickListener;
import static android.content.Context.VIBRATOR_SERVICE;
public class FragmentOne extends Fragment {
private TextView out;
private EditText alter;
private Spinner s;
private Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String text = s.getSelectedItem().toString();
int newage = 404;
double doublenewage = 4.04;
double doubleage;
int intage;
doubleage = Double.parseDouble(alter.getText().toString());
intage = (int) doubleage;
switch (text) {
case "Pferd": {
doublenewage = intage/3.1;
long longpferdage = Math.round(doublenewage);
newage = (int) longpferdage;
if (newage < 31)
out.setText("Du bist ein " + Integer.toString(newage) + " Jahre altes Pferd");
else
out.setText("Du bist höchstwahrscheinlich schon tot, aber theoretisch wärst du ein " + newage + "-Jähriges Pferd.");
}break;
case "Hund": {
newage = intage/7;
if (newage < 15)
out.setText("Du bist ein " + Integer.toString(newage) + " Jahre alter Hund.");
else
out.setText("Du bist höchstwahrscheinlich schon tot, aber theoretisch wärst du ein " + newage + "-Jähriger Hund.");
}break;
case "Meerschweinchen": {
newage = intage/12;
if (newage < 8)
//out.setText("Du bist ein " + Integer.toString(newage) + " Jahre altes Meerie.");
out.setText("Du bist ein "+Integer.toString(newage)+" Jahre altes Meerie.");
else
out.setText("Du bist höchstwahrscheinlich schon tot, aber theoretisch wärst du ein " + newage + "-Jähriges Meerie.");
}break;
}
}
});
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.fragment_one, null);
out = (TextView) layout.findViewById(R.id.out);
alter = (EditText) layout.findViewById(R.id.altereingabe);
s = (Spinner) layout.findViewById(R.id.spinner);
button = (Button) layout.findViewById(R.id.button);
// tvText1 = (TextView) layout.findViewById(R.id.tvFragmentOne);
return layout;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//tvText1.setText("Ok View 1 wurde geändert.");
}
}
これは役立つかもしれません：http://stackoverflow.com/questions/22557780/first-fragment-to-be-added-to-the-main-activity-when-application-starts-up – Yupi
私の主な活動私はすでに他の記事のように断片を始めました。 – Georq