Question

我正在创建一个应用程序，我希望使用PHPMYADMIN中的服务器在ListView中向用户显示所有以前的订单详细信息。

问题：未在活动中获取ListView，获取空白活动而不是ListView

OrdersAdapter.java：

public class OrdersAdapter extends BaseAdapter {

    TextView tName,tId,tOid ;
    String MemberID,resultServer,strMemberID,strName,strOrderID;

    Activity activity;
    LayoutInflater inflater;
    ListView listView;


    public OrdersAdapter(Activity a) {
        // TODO Auto-generated constructor stub
        activity = a;
        inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    }

    public int getCount() {
        return 0;
        // TODO Auto-generated method stub

    }

    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

        public View getView(final int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            View vi = convertView;
            if (convertView == null)
                vi = inflater.inflate(R.layout.listrow_orders, null);  // listrow_cart

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


            tId = (TextView)activity.findViewById(R.id.txtTotalAmount);
            tName = (TextView)activity.findViewById(R.id.txtItemDetails);

            String url = "http://172.16.0.4/res/order_fetch.php";
            Intent intent= activity.getIntent();
            MemberID = intent.getStringExtra("MemberID");
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("sMemberID", MemberID));
            resultServer  = getHttpPost(url,params);

            strMemberID = "";
            strName = "";


            JSONObject c;
            try {
                c = new JSONObject(resultServer);
                strMemberID = c.getString("TotalAmount");               
                strName = c.getString("ItemDetails");

                if(!strMemberID.equals(""))
                    {                   
                        tName.setText(strName);
                        tId.setText(strMemberID);               
                    }
                    else
                    {               
                        tName.setText("-");
                        tId.setText("-");
                    }
                    } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    }       

                }
            return vi;
        }       

                String getHttpPost(String url,List<NameValuePair> params) {
                StringBuilder str = new StringBuilder();
                HttpClient client = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);

                try {
                    httpPost.setEntity(new UrlEncodedFormEntity(params));
                    HttpResponse response = client.execute(httpPost);
                    StatusLine statusLine = response.getStatusLine();
                    int statusCode = statusLine.getStatusCode();
                    if (statusCode == 200) { // Status OK
                        HttpEntity entity = response.getEntity();
                        InputStream content = entity.getContent();
                        BufferedReader reader = new BufferedReader(new InputStreamReader(content));
                        String line;
                        while ((line = reader.readLine()) != null) {
                            str.append(line);
                        }
                    } else {
                        Log.e("Log", "Failed to download result..");
                    }
                } catch (ClientProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return str.toString();  
        }

}

OrdersActivity.java：

    public class OrdersActivity extends Activity 
{               
    ListView mLstView1;
    OrdersAdapter mViewOrdersAdpt;

    @SuppressLint("NewApi")
    @Override

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_orders);   

         mLstView1 = (ListView) findViewById(R.id.listView1);

            mViewOrdersAdpt = new OrdersAdapter(OrdersActivity.this);
            mLstView1.setAdapter(mViewOrdersAdpt);

            mLstView1.setOnItemClickListener(new OnItemClickListener() {

                 public void onItemClick(AdapterView<?> parent, View v,
                         final int position, long id) 
                 {       

                }
            }); 
    }
}

activity_orders.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#ffffff" >

    <include
        android:id="@+id/header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        layout="@layout/header_orders" />

<ListView 
    android:layout_width="match_parent" 
    android:id="@+id/listView1" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_below="@+id/header" 
    android:cacheColorHint="#00000000" 
    android:divider="#b5b5b5" 
    android:dividerHeight="1dp" 
    android:layout_alignParentBottom="true" />

</RelativeLayout>

listrow_orders.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="5dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:layout_marginTop="5dp"
    android:background="@drawable/btn_background"
    android:orientation="horizontal"
    android:padding="5dip" >

<TextView
    android:id="@+id/txtTotalAmount"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView1"
    android:layout_below="@+id/textView1"
    android:textColor="#a60704"
    android:text="TextView" />

<TextView
    android:id="@+id/txtItemDetails"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView3"
    android:layout_below="@+id/textView3"
    android:textColor="#a60704"
    android:text="Item Details Here" />

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/txtTotalAmount"
    android:layout_below="@+id/txtTotalAmount"
    android:layout_marginTop="17dp"
    android:text="Ordered Items:"
    android:textColor="#a60704"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="Total Amount"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:textColor="#a60704" />

</RelativeLayout>

Answer 1

如果您在json内解析Activity而不是BaseAdapter，则会很好，getView()将被多次调用，因此 json 将被解析多次次

在Activity内部AsyncTask内部ArrayList内部ArrayList存储数据中的json抓取代码，如果你有单个ArrayList而不是使用follow else，则需要将多个BaseAdapter constructor传递给onPostExecute use setAdapter(); {1}}

mArrayList

下面， ArrayList<String>是OrdersAdapter ordersAdapter = new OrdersAdapter(MyAct.this,mArrayList);

BaseAdapter

内幕 ArrayList<String> mMyList; public OrdersAdapter(Activity a, ArrayList<String> mList) { activity = a; mMyList = mList; inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE); }

getCount

public int getCount() { return mMyList.size(); } 方法

{{1}}

Answer 2

你的适配器说没有项目，因为getCount（）返回0

Answer 3

OrdersAdapter.java类中的问题你必须以适当的方式覆盖适配器getCount（）方法，如

 public int getCount() {
        return SIZE_OF_ARRAYLIST;

    }

如果你写回0，那么列表就不会显示。所以你需要返回arrayList的大小

Answer 4

传递一个Collection，让我们在构造函数中说出字符串

public OrdersAdapter(Activity a, List stringsToShow) {
    // TODO Auto-generated constructor stub
    activity = a;
    inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   this.stringsToShow = stringsToShow;
}

然后

public int getCount() {
    return stringsToShow.size();

}

并且避免在getView（）中做那么多事情.Kamal karte ho Pande ji ..

Answer 5

不要尝试在getView（）方法中加载数据，因为系统多次调用它。您可以查看这两个链接以了解更好 Yet another getView called multiple times 和第二个链接 custom listview adapter getView method being called multiple times, and in no coherent order 那么现在你需要做些什么来克服这个问题。您从Web加载数据，因此您可以使用asynctask来加载数据并将其传递到类中。检查一下，了解asynctask http://developer.android.com/reference/android/os/AsyncTask.html 从asynctask类中，您可以在类中传递此数据。此类保存数据，然后您可以在主活动中使用此数据。最好在asynctask类中解析json数据。实际上你没有在你的适配器类中传递任何数据。这就是你的listview没有显示任何数据的原因。希望这会奏效。

ListView没有出现在Activity中

5 个答案: