链接我的arrayadapter以发送到我的activity_juice_menu.xml

Question

我在填充ArrayAdapter时遇到问题，因此在activity_main.xml屏幕上点击juice菜单后可以在我的activity_juice_menu.xml上查看

这是我在Android监视器上获得的输出

04-15 18:08:02.930 2839-2839/com.example.vitoriano_vaz.easybayvapes E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.vitoriano_vaz.easybayvapes, PID: 2839
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.vitoriano_vaz.easybayvapes/com.example.vitoriano_vaz.easybayvapes.juiceMenu}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2581)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2641)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1398)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5849)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:763)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:653)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
at com.example.vitoriano_vaz.easybayvapes.juiceMenu.onCreate(juiceMenu.java:24)
at android.app.Activity.performCreate(Activity.java:6570)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2534)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2641) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1398) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5849) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:763) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:653) 
04-15 18:09:19.794 3405-3405/com.example.vitoriano_vaz.easybayvapes E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.vitoriano_vaz.easybayvapes, PID: 3405
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.vitoriano_vaz.easybayvapes/com.example.vitoriano_vaz.easybayvapes.juiceMenu}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2581)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2641)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1398)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5849)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:763)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:653)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
at com.example.vitoriano_vaz.easybayvapes.juiceMenu.onCreate(juiceMenu.java:24)
at android.app.Activity.performCreate(Activity.java:6570)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2534)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2641) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1398) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5849) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:763) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:653) 

JuiceMenu.java 这是我用来声明我的arrayadapter

的类

package com.example.vitoriano_vaz.easybayvapes;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class juiceMenu extends AppCompatActivity {


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


        ArrayAdapter juiceMenu = new ArrayAdapter<String>(this, R.layout.activity_juice_menu);

        ListView listView = (ListView) findViewById(R.id.juiceMenuScreen);
        listView.setAdapter(juiceMenu);


        juiceMenu.add("#1 Blueberry Bombshell");
        juiceMenu.add("#2 Richie Rich");
        juiceMenu.add("#3 Chiquita");
        juiceMenu.add("#4 Afternoon Delight");
        juiceMenu.add("#5 Poppin Otters");
        juiceMenu.add("#6 Viva La Sangria");
        juiceMenu.add("#7 Okole Maluna");
        juiceMenu.add("#8 Carmen Miranda");
        juiceMenu.add("#9 Pomalade");
        juiceMenu.add("#10 Izual");
        juiceMenu.add("#11 Butter Stotch ");
        juiceMenu.add("#12 Blue Bulls");
        juiceMenu.add("#13 Grape Ape");
        juiceMenu.add("#14 Bruce Juice");
        juiceMenu.add("#15 Doc Holiday");
        juiceMenu.add("#16 Peachy Keen");
        juiceMenu.add("#17 Hula");
        juiceMenu.add("#18 New York");
        juiceMenu.add("#19 Al Gore");
        juiceMenu.add("#20 Lux Charms");
        juiceMenu.add("#21 Sailor jack");
        juiceMenu.add("#22 Get Him to the Greek");
        juiceMenu.add("#23 Key We Lie Chi");
        juiceMenu.add("#24 Spring Fling");
        juiceMenu.add("#25 Gumby");
        juiceMenu.add("#26 Chai-Milk");
        juiceMenu.add("#27 Mr. Bean");
        juiceMenu.add("#28 50 Shades of Orange");
        juiceMenu.add("#29 Blue Waffles");
        juiceMenu.add("#30 Enigma");
        juiceMenu.add("#31 Mr. Freeze");
        juiceMenu.add("#32 Cup of Joe");
    }
}

MainActivity.java 主要活动

package com.example.vitoriano_vaz.easybayvapes;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;


public class MainActivity extends AppCompatActivity {
    public void sendMessage(View view){
        Intent intent = new Intent(this, juiceMenu.class);
        startActivity(intent);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void startJuiceMenu(View view) {
        Log.d("MyApp", "button clicked");


    }
}

activity_juice_menu

我希望使用我的arrayadapter填充屏幕

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.vitoriano_vaz.easybayvapes.juiceMenu">
    <ListView
        android:id="@+id/juiceMenuScreen"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:divider="#0000CC"
        android:dividerHeight="0.1dp">
    </ListView>
</LinearLayout>

activity_main.xml中 点击按钮时的主屏幕转到我的activity_juice_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.vitoriano_vaz.easybayvapes.MainActivity"
    android:id="@+id/main_view">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:text="Welcome to East Bay Vapes"
        android:textAllCaps="true"
        android:textColor="#000000"
        android:textSize="20sp"
        android:id="@+id/textView" />
    <Button
        android:id="@+id/juicemenubutton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="sendMessage"
        android:text="@string/JuiceMenu"
        android:layout_marginTop="42dp"
        android:layout_alignParentTop="true" />


</RelativeLayout>