我是android上的新手。我正在使用TypeMenu Activity，其中所有项目都从服务器进入listview，以及其他类SubMenu活动，其中所有项目都来自带图像的服务器。
现在我只希望listview中的所选项目进入TypeMenu活动中的SubMenu活动示例所有项目如Pizza，Pasta等都在listview中...所以我想在下一个例子中显示相关项目，如果我选择披萨那么在subMenu活动中，它应该只显示与Pizza相关的项目，而不是所有项目。关于如何将相关项目带到下一个活动，我感到有点困惑。
这是我的TypeMenu活动：
public class TypeMenu extends AppCompatActivity {
private String TAG = TypeMenu.class.getSimpleName();
String bid;
private ProgressDialog pDialog;
private ListView lv;
private static final String TAG_BID = "bid";
// URL to get contacts JSON
private static String url = "http://cloud.granddubai.com/brtemp/index.php";
ArrayList<HashMap<String, String>> contactList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_type_menu);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
contactList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetContacts().execute();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// getting values from selected ListItem
HashMap<String, String> selected = contactList.get(position);
String keyId = new ArrayList<>(selected.keySet()).get(0);
String type_items = selected.get(keyId);
Intent in = new Intent(getApplicationContext(), SubMenu.class);
// sending pid to next activity
in.putExtra(TAG_BID ,type_items );
startActivityForResult(in, 100);
Toast.makeText(getApplicationContext(),"Toast" +type_items ,Toast.LENGTH_LONG).show();
}
});
}
/**
* Async task class to get json by making HTTP call
*/
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(TypeMenu.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
// Toast.makeText(getApplicationContext(),"Toast",Toast.LENGTH_LONG).show();
}
@Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONArray jsonArry = new JSONArray(jsonStr);
for (int i = 0; i < jsonArry.length(); i++)
{
JSONObject c = jsonArry.getJSONObject(i);
String id = c.getString("id");
String type = c.getString("type");
HashMap<String, String> contact = new HashMap<>();
contact.put("id", id);
contact.put("type", type);
contactList.add(contact);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
TypeMenu.this, contactList,
R.layout.list_item, new String[]{ "type","id"},
new int[]{
R.id.type});
lv.setAdapter(adapter);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
这是我的子菜单活动：
public class SubMenu extends AppCompatActivity {
JSONObject jsonobject;
JSONArray jsonarray;
ListView listview;
ListViewAdapter adapter;
ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
static String RANK = "id";
static String COUNTRY = "name";
static String FLAG = "image";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sub_menu);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
String SelectedId = getIntent().getStringExtra("id");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// Get the view from listview_main.xml
// Execute DownloadJSON AsyncTask
new DownloadJSON().execute();
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> implements AdapterView.OnItemClickListener {
// @Override
// protected void onPreExecute() {
// super.onPreExecute();
// Create a progressdialog
// mProgressDialog = new ProgressDialog(SubMenu.this);
// Set progressdialog title
// mProgressDialog.setTitle("Categories of Main categories.....");
// Set progressdialog message
// mProgressDialog.setMessage("Loading...");
// mProgressDialog.setIndeterminate(false);
// Show progressdialog
// mProgressDialog.show();
// }
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonarray = JsonFunctions
.getJSONfromURL("http://cloud.granddubai.com/broccoli/menu_typeitem.php?id=" + getIntent().getStringExtra("id"));
try {
// Locate the array name in JSON
// jsonarray = jsonobject.getJSONArray("main_menu_items");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
// map.put("id", jsonobject.getString("id"));
map.put("name", jsonobject.getString("name"));
map.put("image", jsonobject.getString("image"));
// Set the JSON Objects into the array
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
listview = (ListView) findViewById(R.id.list1);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(SubMenu.this, arraylist);
// Set the adapter to the ListView
listview.setAdapter(adapter);
listview.setOnItemClickListener(this);
// Close the progressdialog
// mProgressDialog.dismiss();
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
LayoutInflater layoutInflater
= (LayoutInflater)getBaseContext()
.getSystemService(LAYOUT_INFLATER_SERVICE);
View popupView = layoutInflater.inflate(R.layout.popup, null);
final PopupWindow popupWindow = new PopupWindow(
popupView,
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
Button btnDismiss = (Button)popupView.findViewById(R.id.dismiss);
btnDismiss.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
popupWindow.dismiss();
}});
popupWindow.showAsDropDown(view, 3000, -90);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
这是我的TypeMenu活动的Php文件：
<?php
include ('config.php');
$id = $_GET['id'];
$sql = mysqli_query($conn,"SELECT * FROM menu_type ");
$arr = array();
$i=0;
while($result = mysqli_fetch_array($sql))
{
$arr[$i]['id']= $result['id'];
$arr[$i]['type']= $result['type'];
$i++;
}
echo json_encode($arr);
?>
这是我的答案，它正常工作......最后我得到了解决方案
<?php
include ('config.php');
$id = $_GET['id'];
/* assuming main_menu_items table has field "menu_type" */
//$stmt = $mysqli->prepare("SELECT * FROM main_menu_items WHERE type_items=?");
//$stmt->bind_param("i", $id)
$stmt ="SELECT * FROM main_menu_items WHERE type_items='".$id."'";
/*now only submenu items of given type will be selected*/
$sql = mysqli_query($conn, $stmt);
$arr = array();
$i=0;
while($result = mysqli_fetch_array($sql))
{
$arr[$i]['id']= $result['id'];
$arr[$i]['name']= $result['name'];
$arr[$i]['image']=$result['image'];
$i++;
}
echo json_encode($arr);
?>
答案 0 :(得分：0)
由于您将选定的ID传递给下一个活动，因此请在SubMenu活动中通过意图获取您传递的ID并使用该ID进行api调用以获取相关响应并更新您的列表视图
<强>被修改
将您选择的ID传递给onItemClick内的SubMenu活动，如此
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// getting values from selected ListItem
HashMap<String, String> selected = contactList.get(position);
String selectedId= selected.get("id");
Intent in = new Intent(getApplicationContext(), SubMenu.class);
// sending pid to next activity
in.putExtra("id",selectedId);
startActivityForResult(in, 100);
Toast.makeText(getApplicationContext(),"Toast" +type_items ,Toast.LENGTH_LONG).show();
}
});
现在在子菜单活动中获取您的selectedId这样的额外内容并请求服务器获得相应的响应
String SelectedId = getIntent.getStringExtra("id");
答案 1 :(得分：0)
以下是如何修改php代码以获取所需的子菜单项。在代码中，我假设 main_menu_items 表中有 menu_type 字段。将其替换为实际的字段名称。
<?php
include ('config.php');
$id = $_GET['id'];
/* assuming main_menu_items table has field "menu_type" */
$stmt = $mysqli->prepare("SELECT * FROM main_menu_items WHERE menu_type=?");
$stmt->bind_param("i", $id)
/*now only submenu items of given type will be selected*/
$sql = mysqli_query($conn, $stmt);
$arr = array();
$i=0;
while($result = mysqli_fetch_array($sql))
{
$arr[$i]['id']= $result['id'];
$arr[$i]['name']= $result['name'];
$arr[$i]['image']=$result['image'];
$i++;
}
echo json_encode($arr);
?>
在您的SubMenu活动中，您需要从extras读取Id值并将其作为参数传递给php网页。为此，您需要替换此代码行：
jsonarray = JsonFunctions
.getJSONfromURL("http://cloud.granddubai.com/broccoli/menu_typeitem.php");
以下内容：
jsonarray = JsonFunctions
.getJSONfromURL("http://cloud.granddubai.com/broccoli/menu_typeitem.php?id=" + getIntent.getStringExtra("id"));
另外，不要忘记将类型ID传递给第二个活动，因为 sohan shetty 在他的回答中建议。