使用listview显示一堆数据并在Android中以可打包方式传递

Question

所以今天我正在使用listview创建一个项目，但是我想在android java中使用parcelable传递所有选定的值。但是我有点困惑，因为我使用数组来存储数据。这是我的MainActivity.java看起来像：

package com.example.lee;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.view.View;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;

import java.util.ArrayList;

import static android.provider.Contacts.SettingsColumns.KEY;

public class MainActivity extends AppCompatActivity{

    ListView list;
    String[] title;
    int[] image;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        image = new int[]{R.drawable.poster_a_star, R.drawable.poster_aquaman, R.drawable.poster_avengerinfinity, R.drawable.poster_birdbox,
                            R.drawable.poster_bohemian};

        title = new String[]{"A Star is Born", "Aquaman", "Avengers Infinity War", "Bird Box", "Bohemian Rhapsody"};


        ListViewAdapters adapters = new ListViewAdapters(MainActivity.this, image, title, release_info, languages, genres);
        list = (ListView)findViewById(R.id.listview_movie);
        // Binds the Adapter to the ListView
        list.setAdapter(adapters);
//         Capture ListView item click
            list.setOnItemClickListener(new OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view,
                                        int position, long id) {
                    ArrayList<Movie> movies = new ArrayList<>();
                    Movie movie = new Movie();
                    Intent i = new Intent(MainActivity.this, ObjectReceived.class);

                i.putExtra("title",title);
                // Pass listview item click position
                i.putExtra("position", position);
                //Pass image item click image
                i.putExtra("image", image);
                // Open SingleItemView.java Activity
                startActivity(i);
            }

        });
    }
}

我的[[Movie.java类中的这个：

package com.example.lee;
import android.os.Parcel;
import android.os.Parcelable;

public class Movie implements Parcelable {

    private String title;
    private int image;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public int getImage() {
        return image;
    }

    public void setImage(int image) {
        this.image = image;
    }

    protected Movie(Parcel in){
        title = in.toString();
        image = in.readInt();
    }
    public Movie(){

    }
    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(title);
        dest.writeInt(image);
    }

    public static final Creator<Movie> CREATOR = new Creator<Movie>() {
        @Override
        public Movie createFromParcel(Parcel source) {
            return new Movie(source);
        }
        @Override
        public Movie[] newArray(int size) {
            return new Movie[size];
        }
    };
}

这是我的
ObjectReceived.java

类：

package com.example.made_lee;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.TextView;

import java.util.ArrayList;

import static android.provider.Contacts.SettingsColumns.KEY;

public class ObjectReceived extends AppCompatActivity {
    public static final String EXTRA_MOVIE = "extra_person";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_object_received);
        TextView tvObject = findViewById(R.id.object_received);
        ArrayList<Movie> movies = getIntent().getParcelableArrayListExtra(EXTRA_MOVIE);
    }
}

以下是错误消息：
E / AndroidRuntime：致命异常：主要流程：com.example.made_lee，PID：25122java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.made_lee / com.example.made_lee.ObjectReceived}：java.lang.NullPointerException：尝试调用虚拟方法'java.lang.String []com.example.made_lee.Movie.getTitle（）'在null上对象参考在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2817）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2892）在android.app.ActivityThread.-wrap11（未知来源：0）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1593）在android.os.Handler.dispatchMessage（Handler.java:105）在android.os.Looper.loop（Looper.java:164）在android.app.ActivityThread.main（ActivityThread.java:6541）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.Zygote $ MethodAndArgsCaller.run（Zygote.java:240）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:767）原因：java.lang.NullPointerException：尝试调用虚拟方法'java.lang.String []com.example.made_lee.Movie.getTitle（）'在null上对象参考在com.example.made_lee.ObjectReceived.onCreate（ObjectReceived.java:16）在android.app.Activity.performCreate（Activity.java:6975）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1213）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2770）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2892）在android.app.ActivityThread.-wrap11（未知来源：0）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1593）在android.os.Handler.dispatchMessage（Handler.java:105）在android.os.Looper.loop（Looper.java:164）在android.app.ActivityThread.main（ActivityThread.java:6541）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.Zygote $ MethodAndArgsCaller.run（Zygote.java:240）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:767）
列表视图已成功显示，但是每当我单击其中一项时，应用程序将直接停止运行。我认为这是因为我没有正确地将值从MainActivity.java传递给ObjectReceived.java，但是在这里，我对如何将值与数组项传递感到困惑。请帮助我：D谢谢

Answer 1

在您的onItemClick中，您将3个值放入您的意图包中：

i.putExtra("title",title);           
i.putExtra("position", position);
i.putExtra("image", image);

在ObjectReceived活动中，您需要通过键来获取每个值。
因此，这不起作用：
ArrayList<Movie> movies = getIntent().getParcelableArrayListExtra(EXTRA_MOVIE);
}

您需要这样的东西：
Movie movie = new Movie()
movie.setTitle(getIntent().getStringExtra("title")
movie.setImage(getIntent().getIntExtra("image")

放置在您的意图附加中的信息具有一种类型，您需要使用此类型信息来在返修活动中从附加中获取正确的值。