Question

我已经学会了如何创建一个自定义ListItem并向其添加一个可点击的ImageButton，部分归功于这个答案：

how to use onClickListener method of Button on a ListView

但是，我有两个单独的活动，其中包含用户可能想要删除数据的ArrayLists。我是否可以为每个活动添加代码，以检测何时按下特定的ListItem的“删除”按钮，或者我是否必须在ListItemAdapter中定义该方法并尝试找到一种方法来检测当前正在运行的活动？（到目前为止，我的应用程序不需要任何特殊权限，但我确信在以后的版本中会有所改变。）

供参考，这是我的ListItem.java的代码：

package net.player1diary.pocketscribe;

// custom class to be used for an advanced List Item display
public class ListItem {

    private int listIcon; // resource ID of the icon
    private String listText; // the text
    private String listDetail; // details about the list item (optional)
    private boolean deleteEnabled; // whether or not the list item contains a "delete" button

    // constructors
    public ListItem() {};

    public ListItem(int resource, String t, String d, boolean del) {
        this.listIcon = resource;
        this.listText = t;
        this.listDetail = d;
        this.deleteEnabled = del;
    }

    // functions for displaying variables
    public int getListIcon() {
        return this.listIcon;
    }

    public String getListText() {
        return this.listText;
    }

    public String getListDetail() {
        return this.listDetail;
    }

    public boolean getDeleteListItemEnabled() {
        return this.deleteEnabled;
    }

    // functions for altering variables
    public void setListIcon(int newIcon) {
        this.listIcon = newIcon;
    }

    public void setListText(String newText) {
        this.listText = newText;
    }

    public void setListDetail(String newDetail) {
        this.listDetail = newDetail;
    }

    public void setDeleteListItemEnabled(boolean newStatus) {
        this.deleteEnabled = newStatus;
    }
}

ListItemAdapter.java的代码：

package net.player1diary.pocketscribe;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

// custom advanced List Adapter
public class ListItemAdapter extends ArrayAdapter<ListItem> {

    private List<ListItem> objects;

    public ListItemAdapter(Context context, List<ListItem> objects) {
        super(context, R.layout.list_item, objects);
        this.objects = objects;
    }

    // show the customized list items
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View v = convertView;

        if (v == null) {
            LayoutInflater vi;
            vi = LayoutInflater.from(getContext());
            v = vi.inflate(R.layout.list_item, null);
        }

        ListItem p = objects.get(position);

        // display each list item
        if (p != null) {
            ImageView img = (ImageView) v.findViewById(R.id.imgListIcon);
            final TextView text = (TextView) v.findViewById(R.id.txtListText);
            final TextView detail = (TextView) v.findViewById(R.id.txtListDetail);
            ImageButton deleteButton = (ImageButton) v.findViewById(R.id.btnListDeleteItem);

            // prepare the delete button, if it exists
            deleteButton.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO take action, depending on context
                    Toast.makeText(getContext(), "Are you sure you want to delete " + text.getText().toString() + "?", Toast.LENGTH_SHORT).show();
                }
            });

            if (img != null) {
                img.setImageResource(p.getListIcon());
            }

            if (text != null) {
                text.setText(p.getListText());
            }

            if (detail != null) {
                detail.setText(p.getListDetail());
            }

            // hide the detail from view if there is no text there
            if (detail.getText().length() == 0) {
                detail.setVisibility(View.INVISIBLE);
            }

            // hide the delete button from view if it is disabled
            if (!p.getDeleteListItemEnabled()) {
                deleteButton.setVisibility(View.GONE);
            }
        }

        return v;
    }
}

最后，list_item.xml的布局：

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

    <ImageView
        android:id="@+id/imgListIcon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:contentDescription="@string/icon"
        android:maxHeight="@dimen/list_icon"
        android:maxWidth="@dimen/list_icon"
        android:minHeight="32dp"
        android:minWidth="32dp"
        android:src="@drawable/ic_book" />

    <TextView
        android:id="@+id/txtListDetail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/txtListText"
        android:layout_below="@+id/txtListText"
        android:hint="@string/list_item_detail"
        android:textColor="@color/list_detail"
        android:textIsSelectable="false" />

    <TextView
        android:id="@+id/txtListText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/imgListIcon"
        android:ellipsize="end"
        android:hint="@string/list_item"
        android:textColor="@color/list_text"
        android:textIsSelectable="false"
        android:textSize="@dimen/list_item"
        android:textStyle="bold" />

    <ImageButton
        android:id="@+id/btnListDeleteItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_delete" android:contentDescription="@string/delete"/>

</RelativeLayout>

Answer 1

由于您的两个活动都有自己的适配器实例（我推测），您可以创建一个在单击删除时传递位置的界面。活动实现该接口并处理arraylist的正确删除。这样，当单击列表项删除时，正确的活动就会被调用。

在多个活动上使用自定义ListItemAdapter（带有删除按钮）

1 个答案: