Question

我创建了一个自定义的ListView。 ListView包含有关每个对象的一些信息，以及2个按钮，用于编辑和删除。我已通过自定义ArrayList为ListViewAdapter对象添加了该信息。

现在，我希望按钮在单击时更新ArrayList对象。我找不到办法去做。我按照此链接中的说明进行操作..

http://www.migapro.com/click-events-listview-gridview/

程序不会抛出任何错误。但它也没有做任何事情。现在，我只是想通过为每次点击按钮举杯来测试。

ListViewAdapter.getView()方法的代码是：

@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
    ViewHolder holder;

    // check if the view already exists
    // if so, no need to inflate and findViewById again!
    if (convertView == null) {

        // Inflate the custom row layout from your XML.
        convertView = mInflater.inflate(R.layout.list_item, null);

        // create a new "Holder" with subviews
        holder = new ViewHolder();
        holder.itemNameView = (TextView) convertView.findViewById(R.id.item_name);
        holder.itemExpiryView = (TextView) convertView.findViewById(R.id.item_expiry);

        // Taking care of the buttons
        holder.editButton = (Button) convertView.findViewById(R.id.button_edit);
        holder.editButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                ((ListView) parent).performItemClick(v, position, 0); // Let the event be handled in onItemClick()
            }
        });

        holder.deleteButton = (Button) convertView.findViewById(R.id.button_delete);
        holder.deleteButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                ((ListView) parent).performItemClick(v, position, 0); // Let the event be handled in onItemClick()
            }
        });



        // hang onto this holder for future recycling
        convertView.setTag(holder);
    } else {

        // skip all the expensive inflation/findViewById
        // and just get the holder you already made
        holder = (ViewHolder) convertView.getTag();
    }
    // More code after this

    // Grab the title and author from the JSON
    String name = "";
    String expiry = "7 days";

    // Write appropriate codes to obtain values for the string variables above
    name = (String) getItem(position);

    // Send these Strings to the TextViews for display
    holder.itemNameView.setText(name);
    holder.itemExpiryView.setText(expiry);

    return convertView;
}

我在MainActivity中实现了OnItemClickListener（）并编写了这段代码片段来处理按钮点击。

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    long viewId = view.getId();

    if (viewId == R.id.button_edit) {
        Toast.makeText(this, "Edit Button CLicked", Toast.LENGTH_SHORT).show();
    } else if (viewId == R.id.button_delete) {
        Toast.makeText(this, "Delete Button CLicked", Toast.LENGTH_SHORT).show();
    } else {
        Toast.makeText(this, "ListView clicked" + id, Toast.LENGTH_SHORT).show();
    }
}

相应的布局文件如下所示：

<?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">

<TextView
    android:id="@+id/item_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/item_expiry"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/item_name" />

<Button
    android:id="@+id/button_edit"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/item_expiry"
    android:layout_alignParentLeft="true"
    android:text="Edit"
    android:clickable="true" />
    <!--android:onClick="editItem" />-->

<Button
    android:id="@+id/button_delete"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/item_expiry"
    android:layout_alignParentRight="true"
    android:text="Delete"
    android:clickable="true" />
    <!--android:onClick="ItemEdits.deleteItem" />-->


</RelativeLayout>

如果你们需要更多代码片段，请告诉我们。在logcat上找不到任何东西。因此，无法帮助处理任何错误代码/警告消息。非常感谢。

我在这里想要实现的是，当我点击编辑/删除按钮时，我需要调用一个函数来修改存储列表值的ArrayList。不知何故，我需要传递点击项目的位置，以便我可以更新正确的信息。有没有更好的方法呢？如果是这样，那么请帮我解决一下代码示例。

Answer 1

在if（convertview == null）中添加单击操作。需要更改尝试以下内容。这只是一个问题。试试这个，让我知道结果会是什么。

@Override
    public View getView(final int position, View convertView, final ViewGroup parent) {
        ViewHolder holder;

        // check if the view already exists
        // if so, no need to inflate and findViewById again!
        if (convertView == null) {

            // Inflate the custom row layout from your XML.
            convertView = mInflater.inflate(R.layout.list_item, null);

            // create a new "Holder" with subviews
            holder = new ViewHolder();
            holder.itemNameView = (TextView) convertView.findViewById(R.id.item_name);
            holder.itemExpiryView = (TextView) convertView.findViewById(R.id.item_expiry);

            // Taking care of the buttons
            holder.editButton = (Button) convertView.findViewById(R.id.button_edit);
            holder.deleteButton = (Button) convertView.findViewById(R.id.button_delete);


            // hang onto this holder for future recycling
            convertView.setTag(holder);
        } else {

            // skip all the expensive inflation/findViewById
            // and just get the holder you already made
            holder = (ViewHolder) convertView.getTag();
        }

        holder.editButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                ((ListView) parent).performItemClick(v, position, 0); // Let the event be handled in onItemClick()
            }
        });

        holder.deleteButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                ((ListView) parent).performItemClick(v, position, 0); // Let the event be handled in onItemClick()
            }
        });

        // More code after this

        // Grab the title and author from the JSON
        String name = "";
        String expiry = "7 days";

        // Write appropriate codes to obtain values for the string variables above
        name = (String) getItem(position);

        // Send these Strings to the TextViews for display
        holder.itemNameView.setText(name);
        holder.itemExpiryView.setText(expiry);

        return convertView;
    }

注意：在getView方法中使用onclick或使用onItemClick方法。使用两者都会产生一些问题。

处理ListView中的Click事件

1 个答案: