在模拟器中打开后，Android应用程序崩溃

Question

My problem is: When I try to run the app in an emulator, my app just crashes, I don't really know what the problem is... Below is my MainActivity class, androidManifest.xml , activity_main.xml and the logcat crashlog.

MainActivity class:

package com.example.notepadapp;

import android.content.Intent;
import android.media.Image;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ImageButton;
import android.widget.ListView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

private ArrayList<Aantekening> aantekeningen;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Stelt de nieuwe toolbar in
    Toolbar toolbar = findViewById(R.id.custom_toolbar);
    setSupportActionBar(toolbar);

    // Verkrijg de aantekeningen van de database en stel de ListView adapter in
    final DatabaseHandler db = new DatabaseHandler(getApplicationContext());
    aantekeningen = db.getAllNotes();
    ImageButton newEntry = findViewById(R.id.add);
    ListView mylist = findViewById(R.id.notepad_listview);
    final NotepadAdapter notepadAdapter = new NotepadAdapter(this, aantekeningen);
    mylist.setAdapter(notepadAdapter);

    // Stelt de onClick listener methode in welke de NoteActivity activiteit start
    newEntry.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent addNoteActivity = new Intent(MainActivity.this, NoteActivity.class);
            addNoteActivity.putExtra("Optie", "toevoegen");
            startActivity(addNoteActivity);
        }
    });

    //onItemClick (KORT) in ListView start een NoteActivity
    mylist.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            sendEditIntent(position);
        }
    });

    // Stelt de lange onClick listener om verwijdering toe te staan
    //TODO Maak onClickLongListener methode af...
    mylist.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
            // Inflate view
            PopupMenu popup = new PopupMenu(MainActivity.this, view);
            popup.getMenuInflater().inflate(R.menu.note_select_menu, popup.getMenu());
            popup.setGravity(Gravity.END);

            popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                @Override
                public boolean onMenuItemClick(MenuItem menuItem) {

                    // Verkrijg geselcteerde titel
                    switch (menuItem.getItemId()) {
                        case R.id.menuEdit:
                            sendEditIntent(position);
                            break;

                        case R.id.menuDelete:
                            db.deleteNote(aantekeningen.get(position).getId());
                            aantekeningen.remove(position);
                            notepadAdapter.notifyDataSetChanged();
                            break;

                            default:
                                break;
                    }

                    return false;
                }
            });

            popup.show();
            return true;
        }
    });
}

/**
 * @param position  positie van item dat is aangeklikt.
 *                  updateNoteActivity wordt gestart.
 */
private void sendEditIntent(int position) {
    Intent updateNoteActivity = new Intent(MainActivity.this, NoteActivity.class);
    updateNoteActivity.putExtra("optie", "bijwerken");
    updateNoteActivity.putExtra("id", aantekeningen.get(position).getId());
    updateNoteActivity.putExtra("naam", aantekeningen.get(position).getNaam());
    updateNoteActivity.putExtra("aantekening", aantekeningen.get(position).getAantekening());
    startActivity(updateNoteActivity);
}
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity">

<!--Aangepaste toolbar-->
<android.support.v7.widget.Toolbar xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/custom_toolbar"
    android:layout_height="?attr/actionBarSize"
    android:layout_width="match_parent"
    android:theme="@style/customToolbar">

    <!-- Tekst zit in Strings.xml bestand in res map -->
    <!-- Knop om een nieuw taak (ListView Item) toe te voegen -->
    <ImageButton
        android:id="@+id/add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end"
        android:layout_marginEnd="15dp"
        android:src="@drawable/ic_add"
        android:background="@drawable/button_background"
        android:contentDescription="@string/add_note" />

</android.support.v7.widget.Toolbar>

<!-- ListView welke is toegevoegd m.b.v. onClick methode -->
<ListView
    android:id="@+id/notepad_listview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

</LinearLayout>

androidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.notepadapp">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".NoteActivity"></activity>
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <action android:name="android.intent.action.VIEW" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".NoteActivity"/>
</application>

</manifest>

Logcat error log:

2019-02-12 12:58:00.572 4104-4104/? I/Zygote: seccomp disabled by setenforce 0
2019-02-12 12:58:00.573 4104-4104/? I/mple.notepadap: Late-enabling -Xcheck:jni
2019-02-12 12:58:00.588 4104-4104/? W/mple.notepadap: Unexpected CPU variant for X86 using defaults: x86
2019-02-12 12:58:01.035 4104-4104/com.example.notepadapp W/mple.notepadap: JIT profile information will not be recorded: profile file does not exits.
2019-02-12 12:58:01.068 4104-4104/com.example.notepadapp I/chatty: uid=10070(com.example.notepadapp) identical 10 lines
2019-02-12 12:58:01.068 4104-4104/com.example.notepadapp W/mple.notepadap: JIT profile information will not be recorded: profile file does not exits.
2019-02-12 12:58:01.118 4104-4104/com.example.notepadapp I/InstantRun: starting instant run server: is main process
2019-02-12 12:58:01.160 4104-4121/com.example.notepadapp D/libEGL: Emulator has host GPU support, qemu.gles is set to 1.
2019-02-12 12:58:01.180 4104-4104/com.example.notepadapp I/com.example.notepadapp: type=1400 audit(0.0:928): avc: denied { write } for comm=45474C20496E6974 name="property_service" dev="tmpfs" ino=8284 scontext=u:r:untrusted_app:s0:c70,c256,c512,c768 tcontext=u:object_r:property_socket:s0 tclass=sock_file permissive=1
2019-02-12 12:58:01.192 4104-4121/com.example.notepadapp D/vndksupport: Loading /vendor/lib/egl/libGLES_emulation.so from current namespace instead of sphal namespace.
2019-02-12 12:58:01.193 4104-4121/com.example.notepadapp E/libEGL: load_driver(/vendor/lib/egl/libGLES_emulation.so): dlopen failed: library "/vendor/lib/egl/libGLES_emulation.so" not found
2019-02-12 12:58:01.193 4104-4121/com.example.notepadapp D/vndksupport: Loading /vendor/lib/egl/libEGL_emulation.so from current namespace instead of sphal namespace.
2019-02-12 12:58:01.180 4104-4104/com.example.notepadapp I/com.example.notepadapp: type=1400 audit(0.0:929): avc: denied { connectto } for comm=45474C20496E6974 path="/dev/socket/property_service" scontext=u:r:untrusted_app:s0:c70,c256,c512,c768 tcontext=u:r:init:s0 tclass=unix_stream_socket permissive=1
2019-02-12 12:58:01.418 4104-4121/com.example.notepadapp D/libEGL: loaded /vendor/lib/egl/libEGL_emulation.so
2019-02-12 12:58:01.422 4104-4121/com.example.notepadapp D/vndksupport: Loading /vendor/lib/egl/libGLESv1_CM_emulation.so from current namespace instead of sphal namespace.
2019-02-12 12:58:01.423 4104-4121/com.example.notepadapp D/libEGL: loaded /vendor/lib/egl/libGLESv1_CM_emulation.so
2019-02-12 12:58:01.432 4104-4121/com.example.notepadapp D/vndksupport: Loading /vendor/lib/egl/libGLESv2_emulation.so from current namespace instead of sphal namespace.
2019-02-12 12:58:01.436 4104-4121/com.example.notepadapp D/libEGL: loaded /vendor/lib/egl/libGLESv2_emulation.so
2019-02-12 12:58:01.495 4104-4115/com.example.notepadapp I/mple.notepadap: Background concurrent copying GC freed 6767(3MB) AllocSpace objects, 0(0B) LOS objects, 53% free, 1313KB/2MB, paused 282us total 101.684ms
2019-02-12 12:58:01.496 4104-4104/com.example.notepadapp W/mple.notepadap: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (light greylist, reflection)
2019-02-12 12:58:01.497 4104-4104/com.example.notepadapp W/mple.notepadap: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (light greylist, reflection)
2019-02-12 12:58:01.567 4104-4104/com.example.notepadapp D/AndroidRuntime: Shutting down VM


--------- beginning of crash
2019-02-12 12:58:01.571 4104-4104/com.example.notepadapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.notepadapp, PID: 4104
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.notepadapp/com.example.notepadapp.MainActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2914)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:193)
    at android.app.ActivityThread.main(ActivityThread.java:6680)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
 Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
    at android.support.v7.app.AppCompatDelegateImpl.setSupportActionBar(AppCompatDelegateImpl.java:345)
    at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:130)
    at com.example.notepadapp.MainActivity.onCreate(MainActivity.java:34)
    at android.app.Activity.performCreate(Activity.java:7136)
    at android.app.Activity.performCreate(Activity.java:7127)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049) 
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:193) 
    at android.app.ActivityThread.main(ActivityThread.java:6680) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
2019-02-12 12:58:01.579 4104-4104/com.example.notepadapp I/Process: Sending signal. PID: 4104 SIG: 9

What could be the problem that causes these error?

My Javadoc is written in Dutch. Sorry, if that's a problem

Answer 1

You styles.xml file has a tag called AppTheme. The parent theme you have chosen supplies an actionbar.

You need to use a NoActionBar theme if you want to use a Toolbar instead. Which is a good idea.

Answer 2

Just read the exception carefully. The error is being caused by your style theme.

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.notepadapp/com.example.notepadapp.MainActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.

That means you have to use a NoActionBar theme. Just goto your styles.xml file and change the Apptheme.