Java 找不到类ArrayAdapter和listAdapter的符号_Java_Android

Java 找不到类ArrayAdapter和listAdapter的符号

java android

Java 找不到类ArrayAdapter和listAdapter的符号,java,android,Java,Android,大家好，我正在android studio中做一个listview，当我设置listview时，使用下面的代码，我出现了一系列错误。我怎样才能解决它们下面，除了java代码之外，我还添加了xml代码错误： package viewsoftware.quote; import android.os.Bundle; import android.support.design.widget.FloatingActionButton; import android.support.design.

大家好，我正在android studio中做一个listview，当我设置listview时，使用下面的代码，我出现了一系列错误。我怎样才能解决它们

下面，除了java代码之外，我还添加了xml代码

错误：

package viewsoftware.quote;


import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.widget.ListView;
import android.view.View;
import java.util.*;

public class HomeActivity extends AppCompatActivity {

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

        ListView  cantieriListView = (ListView) findViewById( R.id.ListViewCantieri );
        // Create and populate a List of planet names.
        String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars",
                "Jupiter", "Saturn", "Uranus", "Neptune"};
        ArrayList<String> planetList = new ArrayList<String>();
        planetList.addAll( Arrays.asList(planets) );

        // Create ArrayAdapter using the planet list.
        listAdapter = new ArrayAdapter<String>(this, R.layout.row, planetList);

        // Add more planets. If you passed a String[] instead of a List<String>
        // into the ArrayAdapter constructor, you must not add more items.
        // Otherwise an exception will occur.
        listAdapter.add( "Ceres" );
        listAdapter.add( "Pluto" );
        listAdapter.add( "Haumea" );
        listAdapter.add( "Makemake" );
        listAdapter.add( "Eris" );

        // Set the ArrayAdapter as the ListView's adapter.
        cantieriListView.setAdapter( listAdapter );


    }

}

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
        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"
        tools:context=".HomeActivity">

    <android.support.design.widget.AppBarLayout
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_home" android:id="@+id/include"/>

    <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email"/>



</android.support.design.widget.CoordinatorLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/rowTextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:padding="10dp"
              android:textSize="16sp" >
    </TextView>

</LinearLayout>

错误：找不到符号类ArrayAdapter
错误：找不到符号变量listAdapter

家庭活动：

package viewsoftware.quote;


import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.widget.ListView;
import android.view.View;
import java.util.*;

public class HomeActivity extends AppCompatActivity {

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

        ListView  cantieriListView = (ListView) findViewById( R.id.ListViewCantieri );
        // Create and populate a List of planet names.
        String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars",
                "Jupiter", "Saturn", "Uranus", "Neptune"};
        ArrayList<String> planetList = new ArrayList<String>();
        planetList.addAll( Arrays.asList(planets) );

        // Create ArrayAdapter using the planet list.
        listAdapter = new ArrayAdapter<String>(this, R.layout.row, planetList);

        // Add more planets. If you passed a String[] instead of a List<String>
        // into the ArrayAdapter constructor, you must not add more items.
        // Otherwise an exception will occur.
        listAdapter.add( "Ceres" );
        listAdapter.add( "Pluto" );
        listAdapter.add( "Haumea" );
        listAdapter.add( "Makemake" );
        listAdapter.add( "Eris" );

        // Set the ArrayAdapter as the ListView's adapter.
        cantieriListView.setAdapter( listAdapter );


    }

}

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
        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"
        tools:context=".HomeActivity">

    <android.support.design.widget.AppBarLayout
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_home" android:id="@+id/include"/>

    <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email"/>



</android.support.design.widget.CoordinatorLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/rowTextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:padding="10dp"
              android:textSize="16sp" >
    </TextView>

</LinearLayout>

package viewsoftware.quote；
导入android.os.Bundle；
导入android.support.design.widget.FloatingActionButton；
导入android.support.design.widget.Snackbar；
导入android.support.v7.app.AppActivity；
导入android.support.v7.widget.Toolbar；
导入android.widget.ListView；
导入android.view.view；
导入java.util.*；
公共类HomeActivity扩展了AppCompatActivity{
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_home）；
Toolbar Toolbar=（Toolbar）findViewById（R.id.Toolbar）；
设置支持操作栏（工具栏）；
FloatingActionButton fab=（FloatingActionButton）findViewById（R.id.fab）；
fab.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
Snackbar.make（查看“替换为您自己的操作”，Snackbar.LENGTH\u LONG）
.setAction（“Action”，null）.show（）；
}
});
ListView CantieristView=（ListView）findViewById（R.id.ListViewCantieri）；
//创建并填充行星名称列表。
字符串[]行星=新字符串[]{“水星”、“金星”、“地球”、“火星”，
“木星”、“土星”、“天王星”、“海王星”}；
ArrayList planetList=新的ArrayList（）；
planetList.addAll（Arrays.asList（planets））；
//使用行星列表创建ArrayAdapter。
listAdapter=new ArrayAdapter（此，R.layout.row，planetList）；
//添加更多行星。如果传递的是字符串[]而不是列表
//在ArrayAdapter构造函数中，不能添加更多项。
//否则将发生异常。
添加（“Ceres”）；
添加（“Pluto”）；
添加（“Haumea”）；
添加（“Makemake”）；
添加（“Eris”）；
//将ArrayAdapter设置为ListView的适配器。
cantieriListView.setAdapter（列表适配器）；
}
}

acitivity\u home.xml:

package viewsoftware.quote;


import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.widget.ListView;
import android.view.View;
import java.util.*;

public class HomeActivity extends AppCompatActivity {

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

        ListView  cantieriListView = (ListView) findViewById( R.id.ListViewCantieri );
        // Create and populate a List of planet names.
        String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars",
                "Jupiter", "Saturn", "Uranus", "Neptune"};
        ArrayList<String> planetList = new ArrayList<String>();
        planetList.addAll( Arrays.asList(planets) );

        // Create ArrayAdapter using the planet list.
        listAdapter = new ArrayAdapter<String>(this, R.layout.row, planetList);

        // Add more planets. If you passed a String[] instead of a List<String>
        // into the ArrayAdapter constructor, you must not add more items.
        // Otherwise an exception will occur.
        listAdapter.add( "Ceres" );
        listAdapter.add( "Pluto" );
        listAdapter.add( "Haumea" );
        listAdapter.add( "Makemake" );
        listAdapter.add( "Eris" );

        // Set the ArrayAdapter as the ListView's adapter.
        cantieriListView.setAdapter( listAdapter );


    }

}

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
        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"
        tools:context=".HomeActivity">

    <android.support.design.widget.AppBarLayout
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_home" android:id="@+id/include"/>

    <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email"/>



</android.support.design.widget.CoordinatorLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/rowTextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:padding="10dp"
              android:textSize="16sp" >
    </TextView>

</LinearLayout>

row.xml:

package viewsoftware.quote;


import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.widget.ListView;
import android.view.View;
import java.util.*;

public class HomeActivity extends AppCompatActivity {

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

        ListView  cantieriListView = (ListView) findViewById( R.id.ListViewCantieri );
        // Create and populate a List of planet names.
        String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars",
                "Jupiter", "Saturn", "Uranus", "Neptune"};
        ArrayList<String> planetList = new ArrayList<String>();
        planetList.addAll( Arrays.asList(planets) );

        // Create ArrayAdapter using the planet list.
        listAdapter = new ArrayAdapter<String>(this, R.layout.row, planetList);

        // Add more planets. If you passed a String[] instead of a List<String>
        // into the ArrayAdapter constructor, you must not add more items.
        // Otherwise an exception will occur.
        listAdapter.add( "Ceres" );
        listAdapter.add( "Pluto" );
        listAdapter.add( "Haumea" );
        listAdapter.add( "Makemake" );
        listAdapter.add( "Eris" );

        // Set the ArrayAdapter as the ListView's adapter.
        cantieriListView.setAdapter( listAdapter );


    }

}

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
        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"
        tools:context=".HomeActivity">

    <android.support.design.widget.AppBarLayout
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_home" android:id="@+id/include"/>

    <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email"/>



</android.support.design.widget.CoordinatorLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/rowTextView"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:padding="10dp"
              android:textSize="16sp" >
    </TextView>

</LinearLayout>

您缺少导入和变量声明：

import android.widget.ArrayAdapter;
...

public class HomeActivity extends AppCompatActivity {
    final ArrayAdapter<String> listAdapter ;
    ...
}

导入android.widget.ArrayAdapter；
...
公共类HomeActivity扩展了AppCompatActivity{
最终阵列适配器列表适配器；
...
}

您缺少导入和变量声明：

import android.widget.ArrayAdapter;
...

public class HomeActivity extends AppCompatActivity {
    final ArrayAdapter<String> listAdapter ;
    ...
}

导入android.widget.ArrayAdapter；
...
公共类HomeActivity扩展了AppCompatActivity{
最终阵列适配器列表适配器；
...
}

在赋值之前，您必须导入

ArrayAdapter

并声明

listAdapter

变量。在赋值之前，您必须导入

ArrayAdapter

并声明

listAdapter

变量。您现在可以启动应用程序，但在启动崩溃时，这是logcat中的错误：05-31 12:48:10.839 16883-16883/viewsoftware.app E/ArrayAdapter:必须为TextView提供资源ID 05-31 12:48:10.842 16883-16883/viewsoftware.app D/AndroidRuntime:关闭VM 05-31 12:48:11.103 16883-16883/viewsoftware.app E/AndroidRuntime:致命异常：主进程：viewsoftware.app，PID:16883 java.lang.IllegalStateException:ArrayAdapter要求资源ID是一个文本视图问题，使用Initialize ArrayAdapter使用此：

new ArrayAdapter（这是android.R.layout.simple\u list\u item\u 1，planetList）

现在可以使用了，谢谢，我可以问你为什么在某些情况下需要指定：android.R.layoututin在所有情况下你都需要指定ArrayAdapter的布局你现在正在启动应用程序，但在启动崩溃时这是logcat中的错误：05-31 12:48:10.839 16883-16883/viewsoftware.app E/ArrayAdapter:你必须为TextView提供资源ID05-31 12:48:10.842 16883-16883/viewsoftware.app D/AndroidRuntime:关闭VM 05-31 12:48:11.103 16883-16883/viewsoftware.app E/AndroidRuntime:致命异常：主进程：viewsoftware.app，PID:16883 java.lang.IllegalStateException:ArrayAdapter要求资源ID是一个文本视图问题，使用Initialize ArrayAdapter使用此：

new ArrayAdapter（这是android.R.layout.simple\u list\u item\u 1，planetList）

现在可以使用了，谢谢，我可以问您为什么在某些情况下需要指定：android.R.layoutIn在所有情况下，您都需要指定ArrayAdapter的布局