Java Android自定义listview在第一个位置显示最后一项

当我在listview中插入新产品时，该产品将显示在listview中的最后一个位置。现在我想在listview的第一个位置显示最近添加的产品。例如，我的数组产品最初在listview中显示为这样，0>1>2>3，现在我想显示为这样，3>2>1>0。我应该如何在代码中实现它？谢谢你的帮助

AllProductActivity.java

public class AllProductActivity extends ListActivity {

// Progress Dialog
//private ProgressDialog pDialog;

private SweetAlertDialog pDialog;

// Creating JSON Parser object
JSONParser2 jParser = new JSONParser2();
// array list that hold original data
ArrayList<HashMap<String, String>> productsList;

//Array list taht hold search result
ArrayList<HashMap<String, String>> searchResults;



ListView list;
LazyAdapter adapter;


// url to get all products list
private static String url_all_products = "http://gemini888.tk/test4/android_connect/get_all_products.php";

// JSON Node names
public static final String TAG_SUCCESS = "success";
public static final String TAG_PRODUCTS = "products";
public static final String TAG_PID = "uid";
public static final String TAG_NAME = "itemname";
public static final String TAG_PRICE = "price";
public static final String TAG_PATH = "path";

// products JSONArray
JSONArray products = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.all_products);

    final EditText searchBox = (EditText) findViewById(R.id.searchBox);
    list = (ListView)findViewById(android.R.id.list);
    final TextView noProduct = (TextView) findViewById(android.R.id.empty);

    //testing
    if (android.os.Build.VERSION.SDK_INT > 9)
    {
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);
    }

    // Hashmap for ListView
    productsList = new ArrayList<HashMap<String, String>>();

    // Loading products in Background Thread
    new LoadAllProducts().execute();



    searchBox.addTextChangedListener(new TextWatcher() {

        @Override
        public void afterTextChanged(Editable s) {
            // TODO Auto-generated method stub

        }

        @Override
        public void beforeTextChanged(CharSequence s, int start,
                int count, int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
            // get text in edittext
            String searchString = searchBox.getText().toString();
            int textLength = searchString.length();
            //clear initial data
            searchResults.clear();

            for(int i=0; i<productsList.size();i++){
                String listItemName = productsList.get(i).get(TAG_NAME).toString();
                if(textLength<= listItemName.length()){
                    if(searchString.equalsIgnoreCase(listItemName.substring(0,textLength))){
                        searchResults.add(productsList.get(i));
                    }
                }else {
                    noProduct.setText("no items found in our market! Please search again. Make sure all words are spelled correctly.");
                }

            }
            adapter.notifyDataSetChanged();
        }

    });


    // on seleting single product
    // launching Edit Product Screen
    list.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                    .toString();

            // Starting new intent
            Intent in = new Intent(getApplicationContext(),
                    ViewDetailsActivity.class);
            // sending pid to next activity
            in.putExtra(TAG_PID, pid);

            // starting new activity and expecting some response back
            startActivityForResult(in, 100);
        }
    });

}

// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // if result code 100
    if (resultCode == 100) {
        // if result code 100 is received
        // means user edited/deleted product
        // reload this screen again
        Intent intent = getIntent();
        finish();
        startActivity(intent);
    }

}

/**
 * Background Async Task to Load all product by making HTTP Request
 * */
class LoadAllProducts extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        //pDialog = new ProgressDialog(AllProductActivity.this);
        //pDialog.setMessage("Loading products. Please wait...");
        //pDialog.setIndeterminate(false);
        //pDialog.setCancelable(false);
        //pDialog.show();

        pDialog = new SweetAlertDialog(AllProductActivity.this, SweetAlertDialog.PROGRESS_TYPE);
        pDialog.getProgressHelper().setBarColor(Color.parseColor("#A5DC86"));
        pDialog.setTitleText("Loading products. Please wait...");
        //pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();


    }

    /**
     * getting All products from url
     * */
    protected String doInBackground(String... args) {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        // getting JSON string from URL
        JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

        // Check your log cat for JSON reponse
        Log.d("All Products: ", json.toString());

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // products found
                // Getting Array of Products
                products = json.getJSONArray(TAG_PRODUCTS);


                // looping through All Products
                for (int i = 0; i < products.length(); i++) {
                    JSONObject c = products.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_PID);
                    String iname = c.getString(TAG_NAME);
                    String price = c.getString(TAG_PRICE);
                    String path = c.getString(TAG_PATH);

                    // creating new HashMap
                    HashMap<String, String> map = new HashMap<String, String>();

                    // adding each child node to HashMap key => value
                    map.put(TAG_PID, id);
                    map.put(TAG_NAME, iname);
                    map.put(TAG_PRICE, price);
                    map.put(TAG_PATH, path);

                    // adding HashList to ArrayList
                    productsList.add(map);
                }
            } else {
                // no products found
                // Launch Add New product Activity
                Intent i = new Intent(getApplicationContext(),
                        NewProductActivity.class);
                // Closing all previous activities
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        // dismiss the dialog after getting all products
        pDialog.dismiss();

        runOnUiThread(new Runnable() {
            public void run() {
        searchResults = new ArrayList<HashMap<String,String>>(productsList);
        adapter=new LazyAdapter(AllProductActivity.this, searchResults);
        list.setAdapter(adapter);

            }
        });

    }

}

@Override
public boolean onOptionsItemSelected(MenuItem item) { 
    switch (item.getItemId()) {
        case android.R.id.home:
            // app icon in action bar clicked; go home
            Intent intent = new Intent(this, MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
            finish();

            return true;

        default:
            return super.onOptionsItemSelected(item); 
    }
}

public class LazyAdapter extends BaseAdapter {

private Activity activity;
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater=null;
public ImageLoader imageLoader;

public LazyAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
    activity = a;
    data=d;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    imageLoader=new ImageLoader(activity.getApplicationContext());
}

private class ViewHolder{
    ImageView thumb_image;
    TextView pid, itemname, price;
}

ViewHolder viewHolder;


@Override
public int getCount() {
    return data.size();
}

@Override
public Object getItem(int position) {
     return position;
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    View vi=convertView;
    if(convertView==null){
        vi = inflater.inflate(R.layout.list_item, null);
        viewHolder = new ViewHolder();

        viewHolder.pid = (TextView)vi.findViewById(R.id.pid);
        viewHolder.itemname = (TextView)vi.findViewById(R.id.name);
        viewHolder.price = (TextView)vi.findViewById(R.id.price);
        viewHolder.thumb_image = (ImageView)vi.findViewById(R.id.imageView1); //

        vi.setTag(viewHolder);
    }else
        viewHolder=(ViewHolder) vi.getTag();

    HashMap<String, String> song = new HashMap<String, String>();
    song = data.get(position);

    viewHolder.pid.setText(song.get(AllProductActivity.TAG_PID));
    viewHolder.itemname.setText(song.get(AllProductActivity.TAG_NAME));
    viewHolder.price.setText(song.get(AllProductActivity.TAG_PRICE));
    imageLoader.DisplayImage(song.get(AllProductActivity.TAG_PATH), viewHolder.thumb_image); //


    Animation animation;
    animation = AnimationUtils.loadAnimation(activity, R.anim.left_to_right);
    //animation = AnimationUtils.loadAnimation(activity, (position > lastPosition) ?
        //  R.anim.up_from_bottom : R.anim.down_from_top);
    vi.startAnimation(animation);

    return vi;
}

}

公共类AllProductActivity扩展了ListActivity{
//进度对话框
//私人对话；
私人对话；
//创建JSON解析器对象
JSONParser2 jParser=新的JSONParser2（）；
//保存原始数据的数组列表
ArrayList productsList；
//保存搜索结果的数组列表
ArrayList搜索结果；
列表视图列表；
懒散适配器；
//获取所有产品列表的url
私有静态字符串url\u所有产品=”http://gemini888.tk/test4/android_connect/get_all_products.php";
//JSON节点名称
公共静态最终字符串标记_SUCCESS=“SUCCESS”；
公共静态最终字符串TAG_PRODUCTS=“PRODUCTS”；
公共静态最终字符串标记_PID=“uid”；
公共静态最终字符串标记_NAME=“itemname”；
公共静态最终字符串TAG_PRICE=“PRICE”；
公共静态最终字符串标记_PATH=“PATH”；
//产品JSONArray
JSONArray产品=null；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.all_产品）；
最终EditText搜索框=（EditText）findViewById（R.id.searchBox）；
list=（ListView）findViewById（android.R.id.list）；
final TextView noProduct=（TextView）findViewById（android.R.id.empty）；
//测试
如果（android.os.Build.VERSION.SDK_INT>9）
{
StrictMode.ThreadPolicy policy=新建StrictMode.ThreadPolicy.Builder（）.permitAll（）.build（）；
StrictMode.setThreadPolicy（策略）；
}
//ListView的Hashmap
productsList=新的ArrayList（）；
//在后台线程中加载产品
新建LoadAllProducts（）.execute（）；
addTextChangedListener（新的TextWatcher（）{
@凌驾
公共无效后文本已更改（可编辑）{
//TODO自动生成的方法存根
}
@凌驾
更改前的公共无效（字符序列、整数开始、，
整数计数，整数后）{
//TODO自动生成的方法存根
}
@凌驾
public void onTextChanged（字符序列，int start，int before，
整数计数）{
//获取edittext中的文本
String searchString=searchBox.getText（）.toString（）；
int textLength=searchString.length（）；
//清除初始数据
searchResults.clear（）；
对于（int i=0；i要执行此操作，只需更改
getItem（）
逻辑即可

@Override
public Object getItem(int position) {
     return getCount() - position - 1;
}

比如说，如果总计数是2，那么，{索引：0，1}

对于第一项（索引=0）：

2-0-1=1（最后一个索引）

对于第二项（索引=1）：

2-1-1=0（第一个索引）
我认为最好让服务器进行排序，在SQL选择中使用“orderby”

如果你在安卓应用程序中进行排序，一旦数据库发生变化，或者业务逻辑得到改善，你必须在应用程序中重写排序代码，并让所有用户在应用程序中更新。你可以随时在服务器上更改排序算法。
我解决了（黑客攻击了？）将新项添加到ArrayList的0索引中也会出现类似的问题，该索引通过ArrayAdapter更新ListView

不过，我以后不会阅读列表，因此列表结构可能会有问题，但我所关心的只是在ListView顶部添加最新条目的视觉效果

ListView mListView = (ListView) findViewById(R.id.mListView);
//new ArrayAdapter using the activity, a design element for the list, and the list with data
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
//assign the adapter to the listView
mListView.setAdapter(adapter);

不能反转基础集合吗？元素的显示顺序与它存储在hashmap中的顺序完全相同。简单方法-将hashmap更改为任何更好的类型…ArrayList或somth。
//add the entry to the 0th index of the list. This will make the entry appear at the top
list.add(0,""+ resetsToList +": "+currentCount+"");
//tell the adapter that the dataset has changed. This will update the listView
adapter.notifyDataSetChanged();