未通过PutExtra传递正确的整数

Question

我的程序显示一行水平滑动的按钮，其中包含艺术作品的文字描述。单击按钮时，ImageActivity启动以显示相应的艺术品。但是，当我点击任何文本按钮时，它总是显示数组中最后一幅画。

我试图将int ID传递给第二个活动，以便一旦单击相应的描述，它将显示正确的绘画。

非常感谢。

以下是我的主要活动：

import android.content.Intent;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends Activity {

    //CONTAINING PAINTINGS
    private LinearLayout mLinearList;
    private String id;
    private Painting painting;

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

        //REFERENCE THE SCROLLABLE LAYOUT STRUCTURE IN MAIN_SCREEN.XML
        mLinearList = (LinearLayout) findViewById(R.id.linearList);

        //FILL THE SCROLLABLE LAYOUT STRUCTURE WITH PAINTINGS
        fillTextCarousel();

    }

    private void fillTextCarousel() {

        // POPULATE THE LINEAR LIST CAROUSEL WITH PAINTINGS AND DESCRIPTIONS
        Button buttonItem;

        for (int i = 0; i < RenaissanceDatabase.description.length; i++) {
            //STORE THE INDIVIDUAL PAINTINGS AS BUTTONS
            buttonItem = new Button(this);


            painting = new Painting(RenaissanceDatabase.description[i], RenaissanceDatabase.id[i]);

            //USE THE CONTENT DESCRIPTION PROPERTY TO STORE
            //PAINTING DATA

            buttonItem.setContentDescription(painting.getDescription());
            buttonItem.setText(painting.getDescription());

            //SET AN ONCLICK LISTENER FOR THE TEXT BUTTON
            buttonItem.setOnClickListener(displayPainting);

            //ADD THE IMAGE BUTTON TO THE SCROLLABLE LINEAR LIST
            mLinearList.addView(buttonItem);
        }
    }

    private View.OnClickListener displayPainting = new View.OnClickListener() {
         public void onClick(View btn) {
         // COLLECT THE IMAGE STORED FOR THE PAINTING
             //String Painting_ID = Integer.toString(painting.getId());
             Intent imgIntent = new Intent(getApplicationContext(), ImageActivity.class);
             imgIntent.setAction(imgIntent.ACTION_SEND);
             imgIntent.putExtra("image_id", painting.getId());
             startActivity(imgIntent);

         }
    };

我正在尝试将整数ID传递给：

public class ImageActivity extends Activity {

private Painting painting;
private int index;
private int[] IDs;
private String[] Desc;

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

    Intent objIntent = getIntent();
    int ID_Val = objIntent.getIntExtra("image_id", 0);
    ImageView art = (ImageView) findViewById(R.id.imageView2);
    art.setImageResource(ID_Val);
}

}

还有绘画数据库，我要从那里获取身份：

public class RenaissanceDatabase {

    public static String description[] = {
            "Venus of Urbino\nTitan, 1538",
            "St. John the Baptist\nLeonardo da Vinci, 1516",
            "Protrait of Baldassare Castiglione\nRaphael, 1515",
            "The Entombent of Christ\nCaravaggio, 1603",
            "Coronation of the Virgin\nFra Angelico, 1435",
            "Mars and Venus\n Sandro Bottcelli, 1483"};

    public static int id[] = {
            R.drawable.painting1, // VENUS OF URBINO
            R.drawable.painting2, // ST.JOHN BAPTIST
            R.drawable.painting3, // BALDASSARE
            R.drawable.painting4, // ENTOMBENT OF CHRIST
            R.drawable.painting5, // CORONOATION
            R.drawable.painting6  // MARS AND VENUS
    };
}

Answer 1

代码的设置方式非常合理。

看看你用来配置一切的循环。

for (int i = 0; i < RenaissanceDatabase.description.length; i++) {
.....
    painting = new Painting(RenaissanceDatabase.description[i], RenaissanceDatabase.id[i]);
...
}

画在这个循环末尾的值是什么？它是数组中最后一个位置的任何东西。

现在查看您的代码以传递ID：

private View.OnClickListener displayPainting = new View.OnClickListener() {
     public void onClick(View btn) {
         ....
         imgIntent.putExtra("image_id", painting.getId());
         .....
     }
};

呈现的代码从未将“当前绘画”更新为被触摸的绘画。你需要弄清楚用户触摸了哪幅画，并使用那幅画的ID。

另一个答案建议将buttonId设置为绘画的id——这有一些问题，所以我个人不建议这样做。

相反，我会使用适配器和ViewHolder模式，并利用ViewHolder来包含这些元数据。这是一个更具可扩展性的解决方案。

Answer 2

为for循环中的每个按钮设置id-

for (int i = 0; i < RenaissanceDatabase.description.length; i++) {
            //STORE THE INDIVIDUAL PAINTINGS AS BUTTONS
            buttonItem = new Button(this);


            painting = new Painting(RenaissanceDatabase.description[i], RenaissanceDatabase.id[i]);

            //USE THE CONTENT DESCRIPTION PROPERTY TO STORE
            //PAINTING DATA

            buttonItem.setId(painting.getId());
....
        }
    }

然后更改你的OnClickListener-

private View.OnClickListener displayPainting = new View.OnClickListener() {
         public void onClick(View btn) {
    ....
             imgIntent.putExtra("image_id", btn.getId());
             startActivity(imgIntent);

         }
    };