Android 在下一个listview(子菜单)中不显示listview中的选定项
我是android新手。我制作了listview,其中数据来自listview中的服务器,…我想在下一页制作另一个listview,其中子类别将来自主类别。为此,我需要获取所选项目id以供使用。 这是我的代码,它在我运行应用程序时显示空吐司Android 在下一个listview(子菜单)中不显示listview中的选定项,android,json,listview,Android,Json,Listview,我是android新手。我制作了listview,其中数据来自listview中的服务器,…我想在下一页制作另一个listview,其中子类别将来自主类别。为此,我需要获取所选项目id以供使用。 这是我的代码,它在我运行应用程序时显示空吐司 public class TypeMenu extends AppCompatActivity { private String TAG = TypeMenu.class.getSimpleName(); String bid;
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 = "......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) {
pDialog = new ProgressDialog(TypeMenu.this);
pDialog.setMessage("Loading book details.");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
// getting values from selected ListItem
TextView textView = (TextView) view.findViewById(R.id.id);
//where list_content is the id of TextView in listview_item.xml
String text = textView.getText().toString();
System.out.println("Choosen item= : " + text);
Intent in = new Intent(getApplicationContext(), SubMenu.class);
// sending pid to next activity
in.putExtra(TAG_BID ,text);
startActivityForResult(in, 100);
//Toast.makeText(getApplicationContext(),"Toast" + bid,Toast.LENGTH_LONG).show();
}
});
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/**
* 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"},
new int[]{
R.id.type});
lv.setAdapter(adapter);
}
}
}
公共类类型菜单扩展AppCompative活动{
私有字符串标记=TypeMenu.class.getSimpleName();
串标;
私人对话;
私有ListView lv;
私有静态最终字符串标记_BID=“BID”;
//获取联系人JSON的URL
私有静态字符串url=“……com/brtemp/index.php”;
ArrayList联系人列表;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity类型菜单);
Toolbar Toolbar=(Toolbar)findViewById(R.id.Toolbar);
设置支持操作栏(工具栏);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
contactList=新的ArrayList();
lv=(ListView)findViewById(R.id.list);
新建GetContacts().execute();
//论单产品的选择
//启动编辑产品屏幕
lv.setOnItemClickListener(新的AdapterView.OnItemClickListener(){
@凌驾
public void onItemClick(AdapterView父对象、视图、整型位置、长id){
pDialog=新建进度对话框(TypeMenu.this);
setMessage(“加载书籍详细信息”);
pDialog.setUndeterminate(假);
pDialog.setCancelable(真);
pDialog.show();
//从选定的ListItem获取值
TextView TextView=(TextView)view.findViewById(R.id.id);
//其中,list_content是listview_item.xml中TextView的id
String text=textView.getText().toString();
System.out.println(“选择项=:”+文本);
Intent in=新的Intent(getApplicationContext(),子菜单.class);
//将pid发送到下一个活动
in.putExtra(标签投标,文本);
startActivityForResult(in,100);
//Toast.makeText(getApplicationContext(),“Toast”+bid,Toast.LENGTH\u LONG.show();
}
});
}
@凌驾
公共布尔值onOptionsItemSelected(菜单项项){
开关(item.getItemId()){
案例android.R.id.home:
onBackPressed();
返回true;
违约:
返回super.onOptionsItemSelected(项目);
}
}
/**
*异步任务类通过HTTP调用获取json
*/
私有类GetContacts扩展异步任务{
@凌驾
受保护的void onPreExecute(){
super.onPreExecute();
//显示进度对话框
pDialog=新建进度对话框(TypeMenu.this);
setMessage(“请稍候…”);
pDialog.setCancelable(假);
pDialog.show();
//Toast.makeText(getApplicationContext(),“Toast”,Toast.LENGTH_LONG.show();
}
@凌驾
受保护的Void doInBackground(Void…arg0){
HttpHandler sh=新的HttpHandler();
//向url发出请求并获得响应
字符串jsonStr=sh.makeServiceCall(url);
Log.e(标签,“来自url的响应:+jsonStr”);
if(jsonStr!=null){
试一试{
JSONArray jsonArry=新JSONArray(jsonStr);
for(int i=0;i
这是我的list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<!-- Product id (pid) - will be DDEN - used to pass to other activity -->
<TextView
android:id="@+id/id"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/type"
android:textSize="20dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
在
onItemClick中尝试此操作
HashMap<String, String> selected = contactList.get(position);
String id = new ArrayList<>(selected.keySet()).get(0);
String type = selected.get(id);
Toast.makeText(getActivity(), "id = " + id + " type = " + type, Toast.LENGTH_LONG).show();
HashMap selected=contactList.get(位置);
字符串id=新的