Question

如果您对ListViews / RSS feed / Android编程有任何了解，请快速查看此问题。谢谢！

我有一个ListView，其中列出了我的NewsActivity中列出的多个项目（消息），如下所示：

public class NewsActivity extends ListActivity {
private List<Message> messages;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.news);
    loadFeed();
}

private void loadFeed(){
    try{
        BaseFeedParser parser = new BaseFeedParser();
        messages = parser.parse();
        List<String> titles = new ArrayList<String>(messages.size());
        List<String> descriptions = new ArrayList<String>(messages.size());
        List<String> dates = new ArrayList<String>(messages.size());
        for (Message msg : messages){
            titles.add(msg.getTitle());
            descriptions.add(msg.getDescription());
            dates.add(msg.getDate());
        }
        ArrayAdapter<String> adapter = 
            new ArrayAdapter<String>(this, R.layout.row,titles);
        this.setListAdapter(adapter);
    } catch (Throwable t){
        Log.e("AndroidNews",t.getMessage(),t);
    }
}


@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    Intent i = new Intent(this, RSSItem.class);
    //id = the id of the item clicked
    startActivityForResult(i, 1);
    int count = 0;
    for (Message msg : messages) {
        if(count == id){
                 //This is obviously not how it should be done.
                 //But my idea here is that I need to pass the msg to the new RSSItem class.
                 RSSItem item = new RSSItem(msg);
            }
            count++;
    }
}
}

此NewsActivity显示每条消息标题的ListView。我需要帮助的部分是onListItemClick的最后一个函数。该函数创建一个新的RSSItem活动。我只需要在这个新活动中显示该项目的标题，日期和描述（这些都是当前保存在列表中的）。以下是我目前为RSSItem类所做的事情：

public class RSSItem extends Activity {
private Message rssItem;
private String title;
private String date;
private String description;

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

}

public RSSItem(){
    //default constructor: must have 0 arguments
}
public RSSItem(Message msg){
    rssItem = msg;
    title = rssItem.getTitle();
    date = rssItem.getDate();
    description = rssItem.getDescription();
}
}

所以......目前，RSSItem从NewsActivity获取消息，并保存标题，日期和描述。如果这应该以更好/不同的方式完成，请告诉我。

现在我只需要在这个新的RSSItem活动中显示这些信息（标题，日期，描述）。但是，我不确定这是如何工作的/如何做到这一点。它是否完全由R.layout.rssitem文件决定？这是我的R.layout.rssitem文件：

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

<LinearLayout android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView android:id="@+id/title" 
      android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:layout_weight="1" />
</LinearLayout>

<TextView android:id="@+id/description" android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:scrollbars="vertical" />

</LinearLayout>

目前，RSSItem Activity不显示任何内容。任何帮助将不胜感激!!

Answer 1

通常最简单的方法是在调用startActivity之前向Intent添加额外的内容。

Intent i = new Intent(this, RSSItem.class);
//pardon the gross use of fields and key names.
//you would pass in the selected item's fields, more than likely using
//its position, not id
i.putExtra("title", title);
i.putExtra("description", description);
i.putExtra("date", date);

startActivityForResult(i, 1);

然后在RSSItem Activity中的onCreate（）中，您可以通过

检索该意图

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

    Intent receivedIntent = this.getIntent();
    //and pick up the extras
    title = receivedIntent.getStringExtra("title");
    //and so on...

    //instantiate views...
    TextView titleView = (TextView) findViewById(R.id.title);
    titleView.setText(title);

}

如何在多个项目的ListView中显示新活动中的单个项目（Android）

1 个答案: