Listview - 使用 OnItemClickListener 打开一个新活动

Question

我有一个列表视图，当用户使用 OnItemClickListener 选择列表中的项目时，我试图接收“点击”事件。应该发生的是，当单击列表项时，它应该打开一个新活动，但是，每次我运行应用程序并尝试单击任何列表项时都没有任何反应。我一直在试图找出我的代码可能有什么问题，但还没有找到解决方案，希望得到任何建议。

这是我的 Mainactivity 代码：

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //linking of variable to the UI for list view element with id
    newsListView = (ListView) findViewById(R.id.newsFeedList);
    //create adapter
    adapter = new NewsListAdapter (this, R.layout.adapter_news_list, newsListData);
    //attach adapter to list view
    newsListView.setAdapter(adapter);
    EDANewsApp app = EDANewsApp.getInstance();
    //URL that we want to communicate with
    String url = "http://www.efstratiou.info/projects/newsfeed/getList.php";
    //Attach on item click listener to list view
    newsListView.setOnItemClickListener(listListener);
    //Create a request(we expect a JSON array as a response
    JsonArrayRequest jsonRequest = new JsonArrayRequest(url, listener, errorListener);
    //Submit the request
    app.requestQueue.add(jsonRequest);
}
AdapterView.OnItemClickListener listListener = new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        //Create an Intent
        Intent intent = new Intent(MainActivity.this, NewsItemActivity.class);
        NewsRecord record = new NewsRecord();
        //Add parameters
        intent.putExtra("NEWS_ITEM_ID", record.recordId);
        //Retrieve record object for selected news item
        newsListData.get(position);
        startActivity(intent);
    }
};

Answer 1

你没有开始新的活动。

Intent intent = new Intent(MainActivity.this, NewsItemActivity.class);

创建意图后，您必须调用

startActivity(intent)

来自活动。在您的代码中，这将是 MainActivity。 另请检查 NewsItemActivity 是否作为活动添加到 Manifest 文件中

Answer 2

就像亚当指出的那样，你错过了：

startActivity(intent)

所以你的代码必须是这样的：

AdapterView.OnItemClickListener listListener = new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        //Create an Intent
        Intent intent = new Intent(MainActivity.this, NewsItemActivity.class);
        NewsRecord record = new NewsRecord();
        //Add parameters
        intent.putExtra("NEWS_ITEM_ID", record.recordId);
        //Retrieve record object for selected news item
        newsListData.get(position);
       startActivity(intent)
    }
};

Answer 3

@珍妮特·罗德里格斯： 我有你的问题。您缺少适配器。 见：

adapter = new NewsListAdapter (this, R.layout.adapter_news_list, newsListData);

您在此处设置自定义适配器。

但在这里：

AdapterView.OnItemClickListener listListener = new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {});

在这里，您将获得一个从未在列表视图中使用过的不同适配器的 onitemclicklistener。 最后解决方案： 您可以直接从 listview 调用此方法。 喜欢：

newsListView .setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent intent = new Intent(MainActivity.this, NewsItemActivity.class);
    NewsRecord record = new NewsRecord();
    //Add parameters
    intent.putExtra("NEWS_ITEM_ID", record.recordId);
    //Retrieve record object for selected news item
    newsListData.get(position);
   startActivity(intent);

        }
    });

试试这个，如果有更多问题回复：

Answer 4

 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
//linking of variable to the UI for list view element with id
 newsListView = (ListView) findViewById(R.id.newsFeedList);
//create adapter
 adapter = new NewsListAdapter (this, R.layout.adapter_news_list, newsListData);
//attach adapter to list view
newsListView.setAdapter(adapter);
EDANewsApp app = EDANewsApp.getInstance();
//URL that we want to communicate with
String url = "http://www.efstratiou.info/projects/newsfeed/getList.php";
//Attach on item click listener to list view
newsListView.setOnItemClickListener(listListener);
//Create a request(we expect a JSON array as a response
JsonArrayRequest jsonRequest = new JsonArrayRequest(url, listener, errorListener);
//Submit the request
app.requestQueue.add(jsonRequest);

// List View Listener

list.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) {

    Intent intent = new Intent(MainActivity.this, NewsItemActivity.class);
    NewsRecord record = new NewsRecord();
    //Add parameters
    intent.putExtra("NEWS_ITEM_ID", record.recordId);
    //Retrieve record object for selected news item
    newsListData.get(position);
    startActivity(intent);          
            }
        });

}

将此代码替换到您的 oncreate 中，并请在单击侦听器上删除适配器视图，如果不是这样，这肯定会对您有所帮助，如果不是让我知道我会为您找到另一个完美的解决方案