package com.example.vrs.spinnerdemo;
import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import com.netelek.logger.Log;
import com.netelek.rest.utils.RestUtils;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import ie.netelek.xml.schema.tariff.Authority;
import ie.netelek.xml.schema.tariff.AuthorityList;
public class MainActivity extends Activity implements View.OnClickListener, AdapterView.OnItemSelectedListener {
Button btnsubmit;
ListView list22;
//ListView string_list;
Context context = MainActivity.this;
private String[] names = {"Pizza", "Burger", "Chicken", "Peas", "Yess"};
private GoogleApiClient client;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client2;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnsubmit = (Button) findViewById(R.id.submit);
list22 = (ListView)findViewById(R.id.LView);
list22.setAdapter(new AuthorityAdapter(this,new ArrayList<Authority>()));
// Checking internet connection
// ConnectivityManager check = (ConnectivityManager) this.context.getSystemService(Context.CONNECTIVITY_SERVICE);
// NetworkInfo [] info = check.getAllNetworkInfo();
// for(int i =0; i<info.length;i++) {
// if (info[i].getState() == NetworkInfo.State.CONNECTED) {
// Toast.makeText(context, "Internet is connected", Toast.LENGTH_SHORT).show();
// } else if(info[i].getState() ==NetworkInfo.State.DISCONNECTED){
// Toast.makeText(context, "Internet is NOT connected", Toast.LENGTH_SHORT).show();
// }
// }
btnsubmit.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
new MyTask(list22,context).execute();
}
});
//setting the adapter to the above listview
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client2 = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client2.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.vrs.spinnerdemo/http/host/path")
);
AppIndex.AppIndexApi.start(client2, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.vrs.spinnerdemo/http/host/path")
);
AppIndex.AppIndexApi.end(client2, viewAction);
client2.disconnect();
}
class MyTask extends AsyncTask<Void, Void, ArrayList<Authority>> {
Context context;
ListView list22;
MyTask (ListView list22, Context context){
this.list22 = list22;
this.context = context;
}
ArrayAdapter<Authority> adapter;
@Override
protected void onPreExecute() {
adapter = (ArrayAdapter<Authority>) list22.getAdapter();
//Toast.makeText(MainActivity.this,"onPreExecute", Toast.LENGTH_LONG).show();
}
@Override
protected ArrayList<Authority> doInBackground(Void... voids) {
ArrayList<Authority> authList = new ArrayList<>(); //create an arraylist of type authority
try {
//get the authority list from the database
AuthorityList at1 = (AuthorityList) RestUtils.doGet(AuthorityList.class, "https", "172.16.112.121", 443, "/nettariff/webresources/nettariff/authority", "jason.b", "intelligencE4");
authList.addAll(at1.getAuthorityList());
} catch (Exception ex) {
Log.d("ERRRROOOORRR");
}
return authList;
}
@Override
protected void onProgressUpdate(Void... values) {}
@Override
protected void onPostExecute(ArrayList<Authority> authList) {
// string_list = (ListView) findViewById(R.id.string_list);
//ArrayAdapter<String> string_adapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1,names);
// string_list.setAdapter(string_adapter);
ArrayAdapter<Authority> adapter = new AuthorityAdapter(context, authList); //array adapter of type authority
list22.setAdapter(adapter);
Toast.makeText(getApplicationContext(),"onPostExecute", Toast.LENGTH_LONG).show();
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@Override
public void onClick(View view) {}
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public class AuthorityAdapter extends ArrayAdapter<Authority> {
public AuthorityAdapter(Context context, ArrayList<Authority> auths) {
super(context, 0, auths);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Authority auth = getItem(position); //.get(position); //getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
if (convertView == null) { // Lookup view for data population
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row, parent, false);
}
TextView tvName = (TextView) convertView.findViewById(R.id.txt); // Populate the data into the template view using the data object
tvName.setText(auth.getDescription()); // Return the completed view to render on screen
return convertView;
}
}
}
嗨，我正在努力在onPostCreate中创建一个列表视图，代码运行但没有显示列表。我是android工作室的新手。请指出我有的任何错误（可能有一些）。提前谢谢。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.vrs.spinnerdemo.MainActivity"
tools:showIn="@layout/activity_main">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter you bill amount in Rands:"
android:textColor="#000000"
android:textSize="20sp"
android:id="@+id/textView3"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Press button to load list"
android:textColor="#000000"
android:textSize="20sp"
android:id="@+id/textView"
android:layout_below="@+id/BillAmount"
android:layout_alignParentStart="true" />
<EditText
android:id="@+id/BillAmount"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:prompt="@string/bill_prompt"
android:inputType="number"
android:layout_below="@+id/textView3"
android:layout_alignParentStart="true" />
<ListView
android:id="@+id/LView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_below="@+id/textView"
android:layout_above="@+id/submit"></ListView>
<Button
android:id="@+id/submit"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="List of Authorities"
android:textSize="15sp"
android:background="#ff33b5e5"
android:layout_marginBottom="63dp"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true" />
<ListView
android:id="@+id/string_list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:drawSelectorOnTop="false"
android:layout_alignTop="@+id/submit"
android:layout_alignParentStart="true"
android:layout_marginTop="210dp" />
</RelativeLayout>
这是我的自定义数组适配器的xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id = "@+id/txt"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
答案 0 :(得分：0)
替换如下，它可能会有所帮助：
public class MainActivity extends Activity implements View.OnClickListener, AdapterView.OnItemSelectedListener {
Button btnsubmit;
ListView list22;
//ListView string_list;
AuthorityAdapter adapter;
ArrayList<Authority> authList = new ArrayList<>();
//create an arraylist of type authority
Context context = MainActivity.this;
private String[] names = {"Pizza", "Burger", "Chicken", "Peas", "Yess"};
private GoogleApiClient client;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client2;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnsubmit = (Button) findViewById(R.id.submit);
list22 = (ListView)findViewById(R.id.LView);
adapter=new AuthorityAdapter(this,authList);
list22.setAdapter(adapter);
// Checking internet connection
// ConnectivityManager check = (ConnectivityManager) this.context.getSystemService(Context.CONNECTIVITY_SERVICE);
// NetworkInfo [] info = check.getAllNetworkInfo();
// for(int i =0; i<info.length;i++) {
// if (info[i].getState() == NetworkInfo.State.CONNECTED) {
// Toast.makeText(context, "Internet is connected", Toast.LENGTH_SHORT).show();
// } else if(info[i].getState() ==NetworkInfo.State.DISCONNECTED){
// Toast.makeText(context, "Internet is NOT connected", Toast.LENGTH_SHORT).show();
// }
// }
btnsubmit.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
new MyTask(list22,context).execute();
}
});
//setting the adapter to the above listview
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client2 = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client2.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.vrs.spinnerdemo/http/host/path")
);
AppIndex.AppIndexApi.start(client2, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.vrs.spinnerdemo/http/host/path")
);
AppIndex.AppIndexApi.end(client2, viewAction);
client2.disconnect();
}
class MyTask extends AsyncTask<Void, Void, ArrayList<Authority>> {
Context context;
ListView list22;
MyTask (ListView list22, Context context){
this.list22 = list22;
this.context = context;
}
@Override
protected void onPreExecute() {
}
@Override
protected ArrayList<Authority> doInBackground(Void... voids) {
try {
//get the authority list from the database
AuthorityList at1 = (AuthorityList) RestUtils.doGet(AuthorityList.class, "https", "172.16.112.121", 443, "/nettariff/webresources/nettariff/authority", "jason.b", "intelligencE4");
authList.addAll(at1.getAuthorityList());
} catch (Exception ex) {
Log.d("ERRRROOOORRR");
}
return authList;
}
@Override
protected void onProgressUpdate(Void... values) {}
@Override
protected void onPostExecute(ArrayList<Authority> authList) {
adapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(),"onPostExecute", Toast.LENGTH_LONG).show();
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@Override
public void onClick(View view) {}
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public class AuthorityAdapter extends ArrayAdapter<Authority> {
public AuthorityAdapter(Context context, ArrayList<Authority> auths) {
super(context, 0, auths);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Authority auth = getItem(position); //.get(position); //getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
if (convertView == null) { // Lookup view for data population
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row, parent, false);
}
TextView tvName = (TextView) convertView.findViewById(R.id.txt); // Populate the data into the template view using the data object
tvName.setText(auth.getDescription()); // Return the completed view to render on screen
return convertView;
}
}
}