我正在尝试在片段中生成列表视图。代码显示没有错误但是当我尝试启动应用程序时，在progressdialog显示之后，应用程序crashed.below是我的show_fish.java文件。请帮忙。我是android开发的新手。
show_fish.java
package com.rapier.tehranbargh;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.telecom.Connection;
import android.util.Log;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import layout.Ghabz;
import layout.SoratHesabFragment;
import layout.info;
import layout.masaref;
import layout.news;
public class Show_fish extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private ProgressDialog progressDialog;
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> hashMaps;
JSONArray jsonArray = null;
private final String url = "http://192.168.1.106:8080/ghabz.php";
ListView listview;
TextView EmailView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_fish);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
listview = (ListView) findViewById(R.id.listView);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
if (savedInstanceState == null) {
// on first time to display view for first navigation item based on the number
displayView(1); // 2 is your fragment's number for "CollectionFragment"
FragmentTransaction tx = getSupportFragmentManager().beginTransaction();
tx.replace(R.id.content_frame, new news());
tx.commit();
}
new newse().execute();
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.show_fish, 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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
displayView(item.getItemId());
return true;
}
public void displayView(int viewId) {
Fragment fragment = null;
String title = getString(R.string.rapier);
switch (viewId) {
case R.id.nav_news:
fragment = new news();
title = " اخبار ";
break;
case R.id.nav_info:
fragment = new info();
title = " اطلاعات عمومی ";
break;
case R.id.nav_billam:
fragment = new SoratHesabFragment();
title = " صورت حساب ها ";
break;
case R.id.nav_use:
fragment = new masaref();
title = " مصارف ";
break;
case R.id.nav_ghabz:
fragment = new Ghabz();
title = " قبض ";
break;
}
if (fragment != null) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.commit();
}
// set the toolbar title
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle(title);
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
}
class newse extends AsyncTask<String,String,String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog =new ProgressDialog(Show_fish.this);
progressDialog.setMessage("Loading");
progressDialog.show();
}
@Override
protected String doInBackground(String... strings) {
List<NameValuePair> params= new ArrayList<>();
JSONObject json=jsonParser.makeHttpRequest(url,"GET",params);
try {
int t=json.getInt("t");
if(t==1){
jsonArray=json.getJSONArray("news");
for (int i = 0 ;i<jsonArray.length();i++){
JSONObject c = jsonArray.getJSONObject(i);
String ID=c.getString("ID");
String TitrNews=c.getString("TitrNews");
String MiniMatnNews=c.getString("MiniMatnNews");
String MatnNews=c.getString("MatnNews");
String TArikh=c.getString("TArikh");
HashMap<String,String> map = new HashMap<String, String>();
map.put("ID",ID);
map.put("TitrNews",TitrNews);
map.put("MiniMatnNews",MiniMatnNews);
map.put("MatnNews",MatnNews);
map.put("TArikh",TArikh);
hashMaps.add(map);
}
}
else {
Toast.makeText(Show_fish.this," اطلاعاتی دریافت نشد ",Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
progressDialog.cancel();
runOnUiThread(new Runnable() {
@Override
public void run() {
ListAdapter adapter = new SimpleAdapter(Show_fish.this, hashMaps, R.id.listView, new String[]{"TitrNews", "MiniMatnNews", "TArikh"}, new int[]{R.id.titr, R.id.mtn, R.id.data});
listview.setAdapter(adapter);
}
});
}
}
}
片段
<LinearLayout 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="layout.news">
<!-- TODO: Update blank fragment layout -->
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/listView"
android:layout_gravity="center_horizontal" />
</LinearLayout>
news.java 带有列表视图的片段的java文件
public class news extends Fragment {
public news() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_news, container, false);
}
}
并且误解了她
android.view.WindowLeaked: Activity com.rapier.tehranbargh.Show_fish has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{3cdf88f6 V.E..... R......D 0,0-729,232} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:363)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:261)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
at android.app.Dialog.show(Dialog.java:298)
at com.rapier.tehranbargh.Show_fish$newse.onPreExecute(Show_fish.java:205)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
at android.os.AsyncTask.execute(AsyncTask.java:535)
at com.rapier.tehranbargh.Show_fish.onCreate(Show_fish.java:90)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
答案 0 :(得分：0)
将检查添加为：
if(progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}