ListView onItemClickListener

Question

错误：

09-26 13:09:38.551: E/AndroidRuntime(25966): FATAL EXCEPTION: main
09-26 13:09:38.551: E/AndroidRuntime(25966): java.lang.ClassCastException: java.util.HashMap
09-26 13:09:38.551: E/AndroidRuntime(25966):    at com.example.customlayoutlistview.MainActivity$1.onItemClick(MainActivity.java:79)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.widget.AdapterView.performItemClick(AdapterView.java:284)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.widget.ListView.performItemClick(ListView.java:3584)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:1846)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.os.Handler.handleCallback(Handler.java:587)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.os.Handler.dispatchMessage(Handler.java:92)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.os.Looper.loop(Looper.java:130)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at android.app.ActivityThread.main(ActivityThread.java:3687)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at java.lang.reflect.Method.invokeNative(Native Method)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at java.lang.reflect.Method.invoke(Method.java:507)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
09-26 13:09:38.551: E/AndroidRuntime(25966):    at dalvik.system.NativeStart.main(Native Method)

在以下方法实现中找到：

listView.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        // TODO Auto-generated method stub
        int itemPostition = position;
        String itemString = (String)parent.getItemAtPosition(position);
        Toast.makeText(getApplicationContext(), ""+itemPostition+" "+itemString, Toast.LENGTH_SHORT).show();
    }
});

第79行：

String itemString = (String)parent.getItemAtPosition(position);

java类：

public class MainActivity extends Activity {

    ArrayList<HashMap<String, Object>> listFill;
    ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listFill = new ArrayList<HashMap<String, Object>>();
        listView = (ListView) findViewById(R.id.listofviews);

        // Initializing and defining the contents to be filled
        int[] songIcons = { R.drawable.music, R.drawable.music,
                R.drawable.music, R.drawable.music, R.drawable.music };
        String[] songTitle = { "Song One", "Song Two", "Song Three",
                "Song Four", "Song Five" };
        String[] songDescription = { "Description One", "Description Two",
                "Description Three", "Description Four", "Description Five" };

        //Looping through the contents and adding it to our ArrayList 
        for (int i = 0; i < songIcons.length; i++) {
            HashMap<String, Object> toFill = new HashMap<String, Object>();
            //Filling the HashMap first
            toFill.put("songIcon", songIcons[i]);
            toFill.put("songTitle", songTitle[i]);
            toFill.put("songDescription", songDescription[i]);
            //Filling the HashMap inside the ArrayList
            listFill.add(toFill);
        }

        //Creating adapter for the listView
        ListAdapter adapter = new SimpleAdapter(MainActivity.this, listFill,
                R.layout.custom_layout, new String[] { "songIcon", "songTitle",
                        "songDescription" }, new int[] { R.id.list_icon,
                        R.id.list_title, R.id.list_description });
        listView.setAdapter(adapter);
//      setListAdapter(adapter);

        //Implementing on itemClicked

        listView.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position,
                    long id) {
                // TODO Auto-generated method stub
                int itemPostition = position;
                String itemString = (String)parent.getItemAtPosition(position);
                Toast.makeText(getApplicationContext(), ""+itemPostition+" "+itemString, Toast.LENGTH_SHORT).show();
            }
        });

    }

我为什么要犯这个错误？有人能帮忙吗。我正在尝试获取listView上的项目内容

Answer 1

您正在将HashMap对象转换为导致此异常的String对象。

Answer 2

这里：

String itemString = (String)parent.getItemAtPosition(position);

返回的是一个HashMap，您将它转换成一个字符串。

Answer 3

尝尝这个

String i= String.valueOf(position);
Toast.makeText(getApplicationContext(), i, Toast.LENGTH_LONG).show();