不能用我的 JSON Listview 做意图？

Question

目前我在使用 JSON ListView 执行意图时遇到问题。问题是我想在单击按钮时打开我的自定义 JSON 列表，但它被强制关闭。以下是我的代码：

package com.example.tamn;

import com.example.tamn.R;
import com.example.tamn.R.id;
import com.example.tamn.R.layout;
import com.example.tamn.R.menu;

import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;


public class MainActivity2 extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity2, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
public void tab(View view){
    Intent i1=new Intent(this,MainActivity.class);
    startActivity(i1);
}
}

我的自定义列表视图

package com.example.tamn;


import java.util.ArrayList;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.widget.ListView;

import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;

public class MainActivity extends Activity {
    // Log tag
    private static final String TAG = MainActivity.class.getSimpleName();

    // Movies json url
    private static final String url = "http://api.androidhive.info/json/movies.json";
    private ProgressDialog pDialog;
    private List<Movie> movieList = new ArrayList<Movie>();
    private ListView listView;
    private CustomListAdapter adapter;

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

        listView = (ListView) findViewById(R.id.list);
        adapter = new CustomListAdapter(this, movieList);
        listView.setAdapter(adapter);

        pDialog = new ProgressDialog(this);
        // Showing progress dialog before making http request
        pDialog.setMessage("Loading...");
        pDialog.show();

        // changing action bar color
        getActionBar().setBackgroundDrawable(
                new ColorDrawable(Color.parseColor("#1b1b1b")));

        // Creating volley request obj
        JsonArrayRequest movieReq = new JsonArrayRequest(url,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        Log.d(TAG, response.toString());
                        hidePDialog();

                        // Parsing json
                        for (int i = 0; i < response.length(); i++) {
                            try {

                                JSONObject obj = response.getJSONObject(i);
                                Movie movie = new Movie();
                                movie.setTitle(obj.getString("title"));
                                movie.setThumbnailUrl(obj.getString("image"));
                                movie.setRating(((Number) obj.get("rating"))
                                        .doubleValue());
                                movie.setYear(obj.getInt("releaseYear"));

                                // Genre is json array
                                JSONArray genreArry = obj.getJSONArray("genre");
                                ArrayList<String> genre = new ArrayList<String>();
                                for (int j = 0; j < genreArry.length(); j++) {
                                    genre.add((String) genreArry.get(j));
                                }
                                movie.setGenre(genre);

                                // adding movie to movies array
                                movieList.add(movie);

                            } catch (JSONException e) {
                                e.printStackTrace();
                            }

                        }

                        // notifying list adapter about data changes
                        // so that it renders the list view with updated data
                        adapter.notifyDataSetChanged();
                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        VolleyLog.d(TAG, "Error: " + error.getMessage());
                        hidePDialog();

                    }
                });

        // Adding request to request queue
        AppController.getInstance().addToRequestQueue(movieReq);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        hidePDialog();
    }

    private void hidePDialog() {
        if (pDialog != null) {
            pDialog.dismiss();
            pDialog = null;
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity2, menu);
        return true;
    }

}

xml文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:divider="@color/list_divider"
        android:dividerHeight="1dp"
        android:listSelector="@drawable/list_row_selector" />

</RelativeLayout>

另一个xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    tools:context="com.example.tamn.MainActivity2" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="100dp"
        android:text="Button" 
        android:onClick="tab"/>

</RelativeLayout>

Answer 1

当您将电影列表提供给适配器时，它是空的。这就是数据不会显示的原因。

您必须在 CustomListAdapter 类中创建一个方法，例如

setData(List<Movie> movieList){
// Assign to actual list
notifyDataSetChanged();
}