Question

对于您中的许多人来说，这可能是一个愚蠢的问题，但是我找不到在RecyclerView适配器中使用getLifecycle（）。addObserver（）的方法。

Answer 1

我试图对YouTubePlayerView做同样的事情，但发现了一种优雅的方法：

首先，您需要创建一个接口：

package main.app.view;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.border.Border;


import main.java.controllers.MapController;
import main.java.models.MapModel;
import main.resources.ConnectionManager;

public class MapView extends JPanel {
    public Image image;
    private JLabel jlImage;
    private static JButton jbOk;
    private ArrayList<String> comboBoxValues;
    private JComboBox routeComboBox = new JComboBox();
    //private JComboBox<ArrayList<>>;
    private ActionListener actionListener;

    public MapView(){
        super(new FlowLayout());
        setSize(900, 450);
        this.add(getRouteComboBox());
        jbOk = new JButton("OK");
        jbOk.setActionCommand("OK");
        ListenerOfActions listener = new ListenerOfActions();
        jbOk.addActionListener(listener);
        add(jbOk);

    } //constructor end

    public void setComboBoxValues(ArrayList<String> comboBoxValues) {
        this.comboBoxValues = comboBoxValues;
        for (String item: comboBoxValues) {
            routeComboBox.addItem( item );
        }
    }

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


    public MapView getView(){
        jlImage = new JLabel(new ImageIcon(this.image));
        add(jlImage);
        return this;
    }

    public void addListenerOfActions(ActionListener listenForAction) {
        this.actionListener = listenForAction;
    }

    public JComboBox getRouteComboBox(){
        return routeComboBox;
    }

    class ListenerOfActions implements ActionListener {
        int selected = 0;

        @Override
        public void actionPerformed(ActionEvent e) {

            String actionCommand = e.getActionCommand();
            if(actionCommand.equals("OK")) {
                 int selected = getRouteComboBox().getSelectedIndex() + 1;
                 System.out.println(selected);
                System.out.println("print1");

                   MapController.updateMap(selected);
            }
            System.out.println("print2");

        }

        public int getSelected(){
            return this.selected;
        }


    } //class end
} //class end

然后在您的活动中，实现上述接口并覆盖方法：

public interface AddLifecycleCallbackListener {
    void addLifeCycleCallBack(YouTubePlayerView youTubePlayerView);
}

最后，在适配器内部，初始化YoutubePlayerView之后，添加以下代码：

public class MainActivity extends AppCompatActivity implements AddLifecycleCallbackListener
//...
@Override
public void addLifeCycleCallBack(YouTubePlayerView youTubePlayerView) {
    getLifecycle().addObserver(youTubePlayerView);
}

您将必须将上下文传递给适配器。

如何在RecyclerView适配器中使用getLifecycle（）。addObserver（）

1 个答案: