Question

对此可能的解决方案是什么？我在我的应用中向下滑动以刷新listview。但是当我尝试刷新它时，它会创建重复的行。我希望以前更新的行保留在视图中，当我滑动更新时，它应该在顶部附加更新的行（这是正常工作）。唯一的问题是行的重复。这是我的代码。

public class MainActivity extends ActionBarActivity implements SwipeRefreshLayout.OnRefreshListener {

private String TAG = MainActivity.class.getSimpleName();

private String URL_TOP_250 = "My_url";

private SwipeRefreshLayout swipeRefreshLayout;
private ListView listView;
private SwipeListAdapter adapter;
private List<Movie> movieList;

// initially offset will be 0, later will be updated while parsing the json
private int offSet = 0;

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

    listView = (ListView) findViewById(R.id.listView);
    swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);

    movieList = new ArrayList<>();
    adapter = new SwipeListAdapter(this, movieList);
    listView.setAdapter(adapter);

    swipeRefreshLayout.setOnRefreshListener(this);

    /**
     * Showing Swipe Refresh animation on activity create
     * As animation won't start on onCreate, post runnable is used
     */
    swipeRefreshLayout.post(new Runnable() {
                                @Override
                                public void run() {
                                    swipeRefreshLayout.setRefreshing(true);

                                    fetchMovies();
                                }
                            }
    );

}

/**
 * This method is called when swipe refresh is pulled down
 */
@Override
public void onRefresh() {
    fetchMovies();
}

/**
 * Fetching movies json by making http call
 */
private void fetchMovies() {

    // showing refresh animation before making http call
    swipeRefreshLayout.setRefreshing(true);


    String url = URL_TOP_250;

    // Volley's json array request object
    JsonArrayRequest req = new JsonArrayRequest(url,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    Log.d(TAG, response.toString());

                    if (response.length() > 0) {

                        // looping through json and adding to movies list
                        for (int i = 0; i < response.length(); i++) {
                            try {
                                JSONObject movieObj = response.getJSONObject(i);


                                String title = movieObj.getString("title");
                                String desc = movieObj.getString("desc");

                                Movie m = new Movie(title,desc);


                                movieList.add(0,m);
                             //   HashSet hs = new HashSet();
                               // hs.addAll(al);
                                //al.clear();
                                //al.addAll(hs);



                            } catch (JSONException e) {
                                Log.e(TAG, "JSON Parsing error: " + e.getMessage());
                            }
                        }

                        adapter.notifyDataSetChanged();
                    }

                    // stopping swipe refresh
                    swipeRefreshLayout.setRefreshing(false);

                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Server Error: " + error.getMessage());

            //Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();

            // stopping swipe refresh
            swipeRefreshLayout.setRefreshing(false);
        }
    });

    // Adding request to request queue
    MyApplication.getInstance().addToRequestQueue(req);
}

}

**LOG****************
10-23 16:28:14.959  17691-17691/? W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x400207d8)
10-23 16:28:14.969  17691-17691/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.IndexOutOfBoundsException: Invalid index 1, size is 0
            at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:257)
            at java.util.ArrayList.get(ArrayList.java:311)
            at info.androidhive.swiperefresh.helper.SwipeListAdapter.getView(SwipeListAdapter.java:60)
            at android.widget.AbsListView.obtainView(AbsListView.java:1427)
            at android.widget.ListView.makeAndAddView(ListView.java:1802)
            at android.widget.ListView.fillDown(ListView.java:727)
            at android.widget.ListView.fillGap(ListView.java:698)
            at android.widget.AbsListView.trackMotionScroll(AbsListView.java:3390)
            at android.widget.AbsListView.onTouchEvent(AbsListView.java:2267)
            at android.widget.ListView.onTouchEvent(ListView.java:3617)
            at android.view.View.dispatchTouchEvent(View.java:3766)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:897)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1731)
            at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1120)
            at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
            at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1715)
            at android.view.ViewRoot.handleMessage(ViewRoot.java:1787)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:123)
            at android.app.ActivityThread.main(ActivityThread.java:4633)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:521)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

致电

if(movieList!=null) {
  movieList.clear();
}

拍摄电影之前

Answer 2

请按照以下步骤操作：

当onRefresh（）调用时，清除列表视图中的所有项目。
致电网络服务并获取电影列表。
设置列表适配器。

每次刷新listview时刷新列表视图都会复制行

2 个答案: