我正在编写将从网站获取json数组的应用程序。该json数组包括标题，描述和图像。我编写代码和自定义列表视图适配器。列表正在显示但现在我需要显示toast以获取单击哪个列表项。我尝试了很多并搜索但没有得到解决方案。
请帮忙。
ViewCampaigns.java（作为Main.java处理）
package com.therightsol.saveasoul.saveasoul;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
public class viewcampaigns extends AppCompatActivity {
// Progress Dialog
private ProgressDialog pDialog;
private ProgressBar progress;
ListView lv = null;
MyData arrData[] = null;
ArrayList<String> arrlist = null;
// url to get all products list
private static String url_all_campaigns = "http://therightsol.com/saveasoul125/mobile/get_all_campaigns_jsonArr";
private AlertDialog alert;
// products JSONArray
String response = "";
JSONArray jsonArr = null;
ArrayAdapter<String> campaignAdapter;
ListAdapter la;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_campaigns);
progress = (ProgressBar) findViewById(R.id.progressBar1);
lv = (ListView) findViewById(R.id.listView);
ConnectivityManager connManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (mWifi.isConnected()) {
// Do whatever
// Loading campaigns in Background Thread
LoadAllCampaigns task = new LoadAllCampaigns();
task.execute();
}else {
/*new AlertDialog.Builder(viewcampaigns.this)
.setTitle("Your Alert")
.setMessage("Your Message")
.setCancelable(false)
.setPositiveButton("ok", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Whatever...
}
}).create().show();*/
}
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String t = (String) la.getItem(position);
Toast.makeText(getApplicationContext(),"HIIII", Toast.LENGTH_SHORT).show();
}
});
}
class MyData{
public String imgpath;
public String title;
public String shrtdes;
public MyData(){
super();
}
public MyData(String path, String t, String desc){
this.imgpath = path;
this.title = t;
this.shrtdes = desc;
}
}
/**
* Background Async Task to Load all campaigns by making HTTP Request
* */
class LoadAllCampaigns extends AsyncTask<String, Void, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
//Log.i("save a soul", "I am in preexecute.");
super.onPreExecute();
pDialog = new ProgressDialog(viewcampaigns.this);
pDialog.setMessage("Loading Campaigns. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All campaigns from url
* */
protected String doInBackground(String... params) {
Log.i("save a soul", "I am in doinbackground");
//http post
try{
//System.out.println("The output of : doInBackground " +params[0]);
URL url = new URL(url_all_campaigns);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setDoOutput(true);
conn.setConnectTimeout(10000);
conn.setReadTimeout(10000);
System.out.println("The output of getResponsecode: " + conn.getResponseCode());
conn.connect();
String line;
BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
while ((line = br.readLine()) != null) {
response += line;
}
return response;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
pDialog.hide();
// updating UI from Background Thread
Log.i("Save Test", s);
try {
jsonArr = new JSONArray(response);
int l = jsonArr.length();
arrData = new MyData[l];
for (int i = 0; i < jsonArr.length(); i++)
{
JSONObject jsonObj = jsonArr.getJSONObject(i);
System.out.println(jsonObj);
String path = String.valueOf(jsonObj.getString("campaign_image_path"));
String title = String.valueOf(jsonObj.getString("campaign_title"));
String shrtdes = String.valueOf(jsonObj.getString("campaign_short_description"));
path = "http://therightsol.com/saveasoul125/" + path;
Log.i("save a soul", "I am in onPostExecute");
arrData[i] = new MyData(path, title, shrtdes);
}
la = new campaigns_customAdapter(viewcampaigns.this, R.layout.campaignslist, arrData );
/*ListAdapter la = new campaigns_customAdapter(
viewcampaigns.this, title, camp
);*/
lv.setAdapter(la);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String t = (String) la.getItem(position);
Toast.makeText(getApplicationContext(),position, Toast.LENGTH_SHORT).show();
}
});
} catch (JSONException e) {
e.printStackTrace();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, 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);
}
}
广告系列自定义适配器
package com.therightsol.saveasoul.saveasoul;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
public class campaigns_customAdapter extends ArrayAdapter<viewcampaigns.MyData> {
viewcampaigns.MyData [] obj;
Context context;
int resourse;
public campaigns_customAdapter(Context context, int resource, viewcampaigns.MyData[] objects) {
super(context, resource, objects);
this.context=context;
this.resourse=resource;
this.obj=objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(getContext());
//View v = inflater.inflate(R.layout.campaignslist, parent, false);
View row=inflater.inflate(resourse,parent,false);
// Getting Views
TextView title = (TextView) row.findViewById(R.id.campaignTitle);
TextView shrtDesc = (TextView) row.findViewById(R.id.shortDescription);
ImageView campaignimg = (ImageView) row.findViewById(R.id.campaignimage);
title.setText( obj[position].title );
shrtDesc.setText( obj[position].shrtdes);
// Inflating Image
try {
URL url = new URL(obj[position].imgpath);
new DownloadImageTask(campaignimg)
.execute(url.toString());
} catch (MalformedURLException e) {
e.printStackTrace();
}
return row;
}
private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
public DownloadImageTask(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
}
}
}
活动广告系列.xml（具有列表视图的XML文件）
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<ProgressBar
android:id="@+id/progressBar1"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:indeterminate="false"
android:max="10"
android:padding="4dip" >
</ProgressBar>
<ListView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/listView"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
/>
</RelativeLayout>
广告系列列表（列表项的自定义布局的XML）
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/campaignimage"
android:backgroundTintMode="src_over"
android:clickable="false"
android:cropToPadding="false"
android:layout_alignTop="@+id/campaignTitle"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:maxLength="4"
android:ellipsize="end"
android:layout_marginBottom="0dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="30dp"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Title"
android:id="@+id/campaignTitle"
android:layout_alignParentTop="true"
android:layout_alignRight="@+id/campaignimage"
android:layout_alignEnd="@+id/campaignimage"
android:layout_alignParentStart="true"
android:layout_alignParentEnd="true"
android:capitalize="words"
android:textStyle="bold"
android:layout_marginLeft="112dp"
android:layout_marginRight="12dp"
android:layout_marginTop="6dp"
android:typeface="monospace"
android:textColor="#1f6b88"
android:textSize="16dp"
android:layout_marginBottom="4dp"
android:padding="3dp" />
<TextView
android:layout_width="fill_parent"
android:layout_height="66dp"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Small Text"
android:id="@+id/shortDescription"
android:typeface="sans"
android:textStyle="normal"
android:textSize="12dp"
android:paddingLeft="3dp"
android:textColor="#2586a9"
android:layout_below="@+id/campaignTitle"
android:layout_alignLeft="@+id/campaignTitle"
android:layout_alignStart="@+id/campaignTitle"
android:maxLength="14"
android:ellipsize="end"
android:layout_marginRight="12dp"
android:paddingTop="2dp"
android:paddingRight="3dp"
android:paddingBottom="3dp" />
</RelativeLayout>
答案 0 :(得分：0)
不要在Toast语句中使用getApplicationContext（），而是使用ViewCampaigns.this。它应该可以解决你的问题。