After looking at various tuts and SO questions, I'm pretty sure I know how to display limited results within a viewpager from a remote database. Yet when I run the app, I get the following error. I've checked the url through a browser with no errors so I know it can't be null so I'm confused and not sure where this is going wrong. The PHP code limits the results to the last 5 rows in the database in desc order.
LogCat
Process: com.curtrostudios.custompagertest, PID: 22057 java.lang.NullPointerException at com.curtrostudios.custompagertest.MainActivity$2.onResponse(MainActivity.java:59) at com.curtrostudios.custompagertest.MainActivity$2.onResponse(MainActivity.java:50) at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65) at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5072) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) at dalvik.system.NativeStart.main(Native Method)
Main Activity
public class MainActivity extends AppCompatActivity {
private ViewPager pageView;
private String TAG = "Featured View";
private String FEAT_URL = "http://localhost/testing/featured.php";
private ArrayList<FeaturedModel> fdata;
private FeaturedAdapter featAdapt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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();
}
});
pageView = (ViewPager)findViewById(R.id.featuredView);
JsonArrayRequest request = new JsonArrayRequest(FEAT_URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString()); try {
for(int i=0;i<response.length();i++){
String pid=response.getJSONObject(i).getString("pid");
String name=response.getJSONObject(i).getString("prod_name");
String img = response.getJSONObject(i).getString("prod_pic");
fdata.add(new FeaturedModel(pid, name, img));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
featAdapt=new FeaturedAdapter(MainActivity.this, fdata);
pageView.setAdapter(featAdapt);
//dialog.dismiss();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d(TAG, "Error: " + error.getMessage());
//dialog.dismiss();
}
});
VolleyController.getInstance().addToRequestQueue(request, TAG);
}
@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);
}
}
Data Model
public class FeaturedModel {
private String pid;
private String prod_name;
private String prod_pic;
public FeaturedModel(String pid,String prod_name,String prod_pic){
this.pid=pid;
this.prod_name=prod_name;
this.prod_pic=prod_pic;
}
public String getPID(){
return pid;
}
public String getName(){
return prod_name;
}
public String getImageURL(){
return prod_pic;
}
}
Pager Adapter
public class FeaturedAdapter extends PagerAdapter {
private ArrayList<FeaturedModel> feature;
private Context context;
private static LayoutInflater inflater = null;
public FeaturedAdapter(MainActivity mainActivity, ArrayList<FeaturedModel> data) {
feature=data;
context=mainActivity;
inflater = ( LayoutInflater )context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return feature.size();
}
public class Holder
{
TextView ftitle;
NetworkImageView fimg;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Holder holder = new Holder();
View rowView;
rowView = inflater.inflate(R.layout.feature_row, null);
holder.ftitle=(TextView) rowView.findViewById(R.id.featTitle);
holder.fimg=(NetworkImageView)rowView.findViewById(R.id.featImg);
holder.ftitle.setText(feature.get(position).getName());
// If you are using NetworkImageView
holder.fimg.setImageUrl(feature.get(position).getImageURL(), VolleyController.getInstance().getImageLoader());
container.addView(rowView);
return rowView;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((RelativeLayout)object);
}
}
Result from browser
[
{
"pid": "45",
"prod_name": "Product 45",
"prod_pic": "http://localhost/images/testone.png",
"prod_desc": "some description",
},
{
"pid": "44",
"prod_name": "Product 44",
"prod_pic": "http://localhost/images/testtwo.png",
"prod_desc": "some description",
},
{
"pid": "43",
"prod_name": "Product 43",
"prod_pic": "http://localhost/images/testone.png",
"prod_desc": "some description",
},
{
"pid": "42",
"prod_name": "Product 42",
"prod_pic": "http://localhost/images/testtwo.png",
"prod_desc": "some description",
},
{
"pid": "41",
"prod_name": "Product 41",
"prod_pic": "http://localhost/images/testone.png",
"prod_desc": "some description",
}
]
Your ArrayList fdata is not initialized. Call fdata = new ArrayList<>(); before adding/selecting items from it.