We Keep Coding

(Android) When Back pressed, Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference

I've been working on a Android Project (A Basic College Information App), I have three main activities, the user goes in like, Goal/Course Select activity-> CollegeList activity-> College Details Activity. Now When I press back on College Details Activity it crashes with this Error:
Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
Below are the files/code which I think might be responsible for this.....
CollegeListActivity.java file
package com.anurag.college_information.activities;
import static com.anurag.college_information.activities.CareerGoalActivity.GOAL;
import static com.anurag.college_information.activities.CareerGoalActivity.SHARED_PREFS;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.anurag.college_information.R;
import com.anurag.college_information.adapters.RecyclerAdapter;
import com.anurag.college_information.models.ModelClass;
import java.util.ArrayList;
import java.util.List;
public class CollegeListActivity extends AppCompatActivity {
private RecyclerAdapter.RecyclerViewClickListener listener;
//ListView collegeList;
TextView collegeListTitle;
Button courseChange;
RecyclerView recyclerView;
LinearLayoutManager LayoutManager;
RecyclerAdapter recyclerAdapter;
List<ModelClass> cList;
String courseName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_college_list);
collegeListTitle = findViewById(R.id.college_list_title);
courseChange = findViewById(R.id.btn_change_course);
//collegeListTitle.setText(goal + "Colleges");
collegeListTitle.setText(getIntent().getStringExtra("Title") + " Colleges");
initData();
initRecyclerView();
//collegeList = findViewById(R.id.lv_college_list);
courseChange.setTransformationMethod(null);
courseChange.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences sharedPreferences = getSharedPreferences(SHARED_PREFS, MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.clear();
editor.apply();
Intent i = new Intent(CollegeListActivity.this, CareerGoalActivity.class);
startActivity(i);
//finish();
}
});
}
private void initData() {
cList = new ArrayList<>();
courseName = getIntent().getStringExtra("Title");
switch (courseName) {
case "BE/BTech":
cList.add(new ModelClass("https://images.static-collegedunia.com/public/college_data/images/campusimage/1479294300b-5.jpg", "A.P. Shah College of Engineering", "Thane", "8.0"));
break;
case "Pharmacy":
cList.add(new ModelClass("https://images.static-collegedunia.com/public/college_data/images/campusimage/14382400753.jpg", "Bombay College Of Pharmacy", "Mumbai", "9.0"));
break;
}
}
private void initRecyclerView() {
setOnClickListener();
recyclerView = findViewById(R.id.recycler_view);
LayoutManager = new LinearLayoutManager(this);
LayoutManager.setOrientation(RecyclerView.VERTICAL);
recyclerView.setLayoutManager(LayoutManager);
recyclerAdapter = new RecyclerAdapter(cList, listener);
recyclerView.setAdapter(recyclerAdapter);
}
private void setOnClickListener() {
listener = new RecyclerAdapter.RecyclerViewClickListener() {
#Override
public void onClick(View v, int position) {
Intent i = new Intent(CollegeListActivity.this, CollegeDetailsActivity.class);
startActivity(i);
}
};
}
#Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
})
.setNegativeButton("No", null)
.show();
}
}
RecyclerAdapter.java
package com.anurag.college_information.adapters;
import android.content.Context;
import android.content.Intent;
import android.telecom.Call;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.anurag.college_information.activities.CollegeDetailsActivity;
import com.anurag.college_information.models.ModelClass;
import com.anurag.college_information.R;
import com.squareup.picasso.Picasso;
import java.util.List;
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
private List<ModelClass> collegeList ;
private RecyclerViewClickListener listener;
List<String> imageUrl, collegeName, collegeLocation, collegeRating;
public RecyclerAdapter(List<ModelClass> collegeList, RecyclerViewClickListener listener){
this.collegeList=collegeList;
this.listener = listener;
}
#NonNull
#Override
public RecyclerAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.college_list_single_row, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull RecyclerAdapter.ViewHolder holder, int position) {
String imageLink = collegeList.get(position).getImageLink();
//int img = collegeList.get(position).getCollegeImage();
String cName = collegeList.get(position).getCollegeName();
String cRating = collegeList.get(position).getCollegeRating();
String cLocation = collegeList.get(position).getLocation();
Picasso.get().load(imageLink).into(holder.imageView);
//holder.setData(img, cName, cRating);
holder.setData(imageLink, cName, cLocation ,cRating);
}
#Override
public int getItemCount() {
return collegeList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private ImageView imageView;
private TextView collegeName, collegeRating, collegeLocation;
public ViewHolder(#NonNull View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.college_image);
collegeName = itemView.findViewById(R.id.college_name);
collegeRating = itemView.findViewById(R.id.college_rating);
collegeLocation = itemView.findViewById(R.id.college_location);
itemView.setOnClickListener(this);
}
public void setData(String imageLink, String cName, String cLocation, String cRating) {
//imageView.setImageResource(img);
Picasso.get().load(imageLink).error(R.drawable.error).into(imageView);
collegeName.setText(cName);
collegeRating.setText(cRating);
collegeLocation.setText(cLocation);
}
#Override
public void onClick(View v) {
listener.onClick(v, getAdapterPosition());
Intent i = new Intent(v.getContext(), CollegeDetailsActivity.class);
i.putExtra("collegeImage", collegeList.get(getAdapterPosition()).getImageLink());
i.putExtra("collegeName", collegeList.get(getAdapterPosition()).getCollegeName());
i.putExtra("collegeRating", collegeList.get(getAdapterPosition()).getCollegeRating());
i.putExtra("collegeLocation", collegeList.get(getAdapterPosition()).getLocation());
v.getContext().startActivity(i);
}
}
public interface RecyclerViewClickListener{
void onClick(View v, int position);
}
}
CollegeDetailsActivity.java
package com.anurag.college_information.activities;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.anurag.college_information.R;
import com.squareup.picasso.Picasso;
public class CollegeDetailsActivity extends AppCompatActivity {
Button btnApply;
ImageView dCollegeImage;
TextView dCollegeName, dCollegeRating, dCollegeLocation;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_college_details);
dCollegeImage = findViewById(R.id.details_college_image);
dCollegeName = findViewById(R.id.details_college_name);
dCollegeRating = findViewById(R.id.details_college_rating);
dCollegeLocation = findViewById(R.id.details_college_location);
btnApply = findViewById(R.id.btn_apply);
Intent i = getIntent();
String cn = i.getStringExtra("collegeName");
String cr = i.getStringExtra("collegeRating");
String ci = i.getStringExtra("collegeImage");
String cl = i.getStringExtra("collegeLocation");
Picasso.get().load(ci).error(R.drawable.error).into(dCollegeImage);
dCollegeName.setText(cn);
dCollegeRating.setText(cr);
dCollegeLocation.setText(cl);
btnApply.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "The institute will be notified, of your application", Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "The college will contact you, Thank you", Toast.LENGTH_LONG).show();
}
});
}
#Override
public void onBackPressed() {
Intent i = new Intent(CollegeDetailsActivity.this, CollegeListActivity.class);
startActivity(i);
}
}
This is the Error Screenshot:
I'm pretty new to android I've just worked on just 4 to 5 projects,
Any Assistance will be appreciated, Thank You
The commented Out code, is just a normal listview I implemented just In Case, I have to remove the recycler view.

This will probably go away if you don't override onBackPressed in CollegeDetailsActivity. Instead of going back to an activity that had a valid "Title" string extra, the code you posted will go to a new activity where "Title" isn't defined, then get a NullPointerException since courseName will be null in initData (which the error message tells you results in an error on line 81 in that method). Using a null string in a switch results in that type of error
Just remove your onBackPressed entirely in CollegeDetailsActivity.

How do get a URI from a ListView item with onclick?

Hi everybody fairly new to java and android development, I need help to get the URI from the item that the user clicks on so that it can be played.
This is all the code I have thus far please help for I have been stuck at this specific problem for some time now.
the problem is in the onItemClickListner.
package com.example.musicplayer;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.media.AudioAttributes;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){
if (ContextCompat.checkSelfPermission(this,Manifest.permission.READ_EXTERNAL_STORAGE)==PackageManager.PERMISSION_GRANTED){
Log.i("Permission ","gRANTED");
}
}
}
ListView musicListView;
ArrayList<String> musicArrayList;
ArrayAdapter<String> adapter;
MediaPlayer mediaPlayer;
Uri songUri;
public void play(View view){
}
public void pause(View view){
}
public void stop(View view){
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
this.getSupportActionBar().hide();
}catch (Exception e){
setContentView(R.layout.activity_main);
}
if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},1);
}
musicListView= (ListView) findViewById(R.id.musicListView);
musicArrayList= new ArrayList<>();
adapter = new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,android.R.id.text1, musicArrayList);
String[] proj = { MediaStore.Audio.Media.DISPLAY_NAME };// Can include more data for more details and check it.
Cursor audioCursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, proj, null, null, null);
if(audioCursor != null){
if(audioCursor.moveToFirst()){
do{
int audioIndex = audioCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
musicArrayList.add(audioCursor.getString(audioIndex));
}while(audioCursor.moveToNext());
}
}
audioCursor.close();
musicListView.setAdapter(adapter);
musicListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
songUri =//////PLEASE HELP ME GET THIS//////;
MediaPlayer mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioAttributes(
new AudioAttributes.Builder()
.setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
.setUsage(AudioAttributes.USAGE_MEDIA)
.build()
);
try {
mediaPlayer.setDataSource(getApplicationContext(), songUri);
} catch (IOException e) {
e.printStackTrace();
}
try {
mediaPlayer.prepare();
} catch (IOException e) {
e.printStackTrace();
}
mediaPlayer.start();
}
});
}
}

I haven't yet tried this solution but in general the way pointed in this answer can solve your problem.
https://stackoverflow.com/a/10461112/3400640

How to ask for Location Permission up-front on App Launch in Java

I am trying to ask for Device permission Upfront on app Launch to no avail. I am not using any Libraries since I am following this document(https://developer.android.com/training/permissions/requesting)
and I am intending to use it, What am I doing wrong?
Here is my Manifest
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
This is my what I have tried on MainActivity and my minSdkVersion is 26
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
private static final int REQUEST_CODE = 100;
private Activity mActivity;
private Context mContext;
String[] appPermissions = {
Manifest.permission.ACCESS_FINE_LOCATION,
Manifest.permission.ACCESS_COARSE_LOCATION
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mActivity = MainActivity.this;
mContext = getApplicationContext();
requestAppPermissions();
}
private void requestAppPermissions() {
try {
if(ContextCompat.checkSelfPermission(
mActivity,Manifest.permission.ACCESS_FINE_LOCATION
)+ContextCompat.checkSelfPermission(
mActivity,Manifest.permission.ACCESS_COARSE_LOCATION
)== PackageManager.PERMISSION_GRANTED
){
///perform action
Toast.makeText(mContext,"Permissions already granted",Toast.LENGTH_SHORT).show();
}else {
if (
//Do something when permission is not granted
ActivityCompat.shouldShowRequestPermissionRationale(
mActivity, Manifest.permission.ACCESS_FINE_LOCATION
) || ActivityCompat.shouldShowRequestPermissionRationale(
mActivity, Manifest.permission.ACCESS_COARSE_LOCATION
)
) {
AlertDialog.Builder builder = new AlertDialog.Builder(mActivity);
builder.setMessage("Location Permission is required by App.");
builder.setTitle("Please grant location Permission");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
ActivityCompat.requestPermissions(
mActivity, new String[]{
Manifest.permission.ACCESS_FINE_LOCATION,
Manifest.permission.ACCESS_COARSE_LOCATION
},
REQUEST_CODE
);
}
});
builder.setNeutralButton("Cancel", null);
AlertDialog dialog = builder.create();
dialog.show();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
switch (requestCode){
case REQUEST_CODE:{
if(
(
grantResults.length>0)&&(
grantResults[0]+grantResults[1]
==PackageManager.PERMISSION_GRANTED
)
){
Toast.makeText(mContext,"Permissions granted.",Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(mContext,"Permissions Denied.",Toast.LENGTH_SHORT).show();
}
return;
}
}
}
}

Glide: How to stop glide from loading images from cache instead load from server each time

I tried everything possible but couldn't try to figure out how to update images to glide whenever my json is updated
MY android app initally loads images from json using glide for firsttime after that it only load images from cache.It doesnot load images that are updated on server till i delete the app and reinstall it
I tried using diskCacheStrategy(DiskCacheStrategy.NONE) and .skipMemoryCache(true) but nothing happened
Glide.with(mContext).load(image.getMedium())
.thumbnail(0.5f)
.crossFade()
.diskCacheStrategy(DiskCacheStrategy.NONE)
.skipMemoryCache(true)
.into(holder.thumbnail);
This is my code GalleryAdapter.java
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.DiskCacheStrategy;
import java.util.List;
import com.bumptech.glide.signature.StringSignature;
import com.dailysolutions.sn.R;
import com.dailysolutions.sn.model.Image;
/**
* Created by Sagunesh on 31/03/16.
*/
public class GalleryAdapter extends RecyclerView.Adapter<GalleryAdapter.MyViewHolder> {
private List<Image> images;
private Context mContext;
public class MyViewHolder extends RecyclerView.ViewHolder {
public ImageView thumbnail;
public MyViewHolder(View view) {
super(view);
thumbnail = (ImageView) view.findViewById(R.id.thumbnail);
}
}
public GalleryAdapter(Context context, List<Image> images) {
mContext = context;
this.images = images;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.gallery_thumbnail, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Image image = images.get(position);
Glide.with(mContext).load(image.getMedium())
.thumbnail(0.5f)
.crossFade()
.diskCacheStrategy(DiskCacheStrategy.NONE)
.skipMemoryCache(true)
.into(holder.thumbnail);
}
#Override
public int getItemCount() {
return images.size();
}
public interface ClickListener {
void onClick(View view, int position);
void onLongClick(View view, int position);
}
public static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
private GestureDetector gestureDetector;
private GalleryAdapter.ClickListener clickListener;
public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final GalleryAdapter.ClickListener clickListener) {
this.clickListener = clickListener;
gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
#Override
public void onLongPress(MotionEvent e) {
View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null) {
clickListener.onLongClick(child, recyclerView.getChildPosition(child));
}
}
});
}
#Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
View child = rv.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
clickListener.onClick(child, rv.getChildPosition(child));
}
return false;
}
#Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
}
}
Here is the code of MainActivity.java
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.MenuItem;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.bumptech.glide.Glide;
import com.dailysolutions.sn.R;
import com.dailysolutions.sn.adapter.GalleryAdapter;
import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdView;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.google.android.gms.ads.AdRequest;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import com.dailysolutions.sn.app.AppController;
import com.dailysolutions.sn.model.Image;
import com.google.android.gms.ads.InterstitialAd;
import java.util.ArrayList;
public class MainActivity extends BaseActivity {
private DrawerLayout drawerLayout;
private Toolbar toolbar;
private String TAG = MainActivity.class.getSimpleName();
private static final String endpoint = "https://www.freesabkuch.com/api_mehndi/glide.json";
private ArrayList<Image> images;
private ProgressDialog pDialog;
private GalleryAdapter mAdapter;
private RecyclerView recyclerView;
private AdView mAdView;
InterstitialAd interstitial;
// Our created menu to use
private Menu mymenu;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
initNavigationDrawer();
checkConnectivity();
//advertisement
mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder()
.build();
mAdView.loadAd(adRequest);
// Prepare the Interstitial Ad
interstitial = new InterstitialAd(MainActivity.this);
// Insert the Ad Unit ID
interstitial.setAdUnitId(getString(R.string.admob_interstitial_id));
interstitial.loadAd(adRequest);
// Prepare an Interstitial Ad Listener
interstitial.setAdListener(new AdListener() {
public void onAdLoaded() {
// Call displayInterstitial() function
displayInterstitial();
}
});
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
pDialog = new ProgressDialog(this);
images = new ArrayList<>();
mAdapter = new GalleryAdapter(getApplicationContext(), images);
RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(getApplicationContext(), 2);
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(mAdapter);
recyclerView.addOnItemTouchListener(new GalleryAdapter.RecyclerTouchListener(getApplicationContext(), recyclerView, new GalleryAdapter.ClickListener() {
#Override
public void onClick(View view, int position) {
Bundle bundle = new Bundle();
bundle.putSerializable("images", images);
bundle.putInt("position", position);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
SlideshowDialogFragment newFragment = SlideshowDialogFragment.newInstance();
newFragment.setArguments(bundle);
newFragment.show(ft, "slideshow");
}
#Override
public void onLongClick(View view, int position) {
}
}));
fetchImages();
}
public void displayInterstitial() {
// If Ads are loaded, show Interstitial else show nothing.
if (interstitial.isLoaded()) {
interstitial.show();
}
}
#Override
public void onResume() {
// Start or resume the game.
super.onResume();
displayInterstitial();
}
#Override
public void onStart() {
super.onStart();
displayInterstitial();
}
private void fetchImages() {
pDialog.setMessage("Downloading....");
pDialog.show();
JsonArrayRequest req = new JsonArrayRequest(endpoint,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
pDialog.hide();
images.clear();
for (int i = 0; i < response.length(); i++) {
try {
JSONObject object = response.getJSONObject(i);
Image image = new Image();
image.setName(object.getString("name"));
JSONObject url = object.getJSONObject("url");
image.setSmall(url.getString("small"));
image.setMedium(url.getString("medium"));
image.setLarge(url.getString("large"));
image.setTimestamp(object.getString("timestamp"));
images.add(image);
} catch (JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
}
}
mAdapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Error: " + error.getMessage());
pDialog.hide();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(req);
}
#Override
public void onBackPressed() {
exit();
}
public void initNavigationDrawer() {
NavigationView navigationView = (NavigationView)findViewById(R.id.navigation_view);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
int id = menuItem.getItemId();
switch (id){
case R.id.home:
Toast.makeText(getApplicationContext(),"Home",Toast.LENGTH_SHORT).show();
drawerLayout.closeDrawers();
break;
case R.id.share:
Toast.makeText(getApplicationContext(),"Share",Toast.LENGTH_SHORT).show();
drawerLayout.closeDrawers();
try {
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("text/plain");
i.putExtra(Intent.EXTRA_SUBJECT, "My application name");
String sAux = "\nLet me recommend you this application\n\n";
sAux = sAux + "https://play.google.com/store/apps/details?id=Orion.Soft \n\n";
i.putExtra(Intent.EXTRA_TEXT, sAux);
startActivity(Intent.createChooser(i, "choose one"));
} catch(Exception e) {
//e.toString();
}
case R.id.trash:
Toast.makeText(getApplicationContext(),"Drawer Closed",Toast.LENGTH_SHORT).show();
drawerLayout.closeDrawers();
break;
case R.id.logout:
exit();
}
return true;
}
});
View header = navigationView.getHeaderView(0);
TextView tv_email = (TextView)header.findViewById(R.id.tv_email);
tv_email.setText("Daily Solutions");
drawerLayout = (DrawerLayout)findViewById(R.id.drawer);
ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this,drawerLayout,toolbar,R.string.drawer_open,R.string.drawer_close){
#Override
public void onDrawerClosed(View v){
super.onDrawerClosed(v);
}
#Override
public void onDrawerOpened(View v) {
super.onDrawerOpened(v);
}
};
drawerLayout.addDrawerListener(actionBarDrawerToggle);
actionBarDrawerToggle.syncState();
}
private void checkConnectivity(){
if(ConnectionHelper.isConnectedOrConnecting(getApplicationContext())) {
hideErrorsBar(true);
}else {
//hideErrorsBar(false);
Intent Intent = new Intent(MainActivity.this,NoInternet.class);
startActivity(Intent);
finish();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Add our menu
getMenuInflater().inflate(R.menu.menu_main, menu);
// We should save our menu so we can use it to reset our updater.
mymenu = menu;
//
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()) {
case R.id.action_refresh:
// Do animation start
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ImageView iv = (ImageView)inflater.inflate(R.layout.iv_refresh, null);
Animation rotation = AnimationUtils.loadAnimation(this, R.anim.rotate_refresh);
rotation.setRepeatCount(Animation.INFINITE);
iv.startAnimation(rotation);
item.setActionView(iv);
new UpdateTask(this).execute();
return true;
}
return super.onOptionsItemSelected(item);
}
public void resetUpdating()
{
// Get our refresh item from the menu
MenuItem m = mymenu.findItem(R.id.action_refresh);
if(m.getActionView()!=null)
{
// Remove the animation.
m.getActionView().clearAnimation();
m.setActionView(null);
}
}
}

You can use Signature for invalidating cache and load image from network. Try
Glide.with(Fragment/context)
.load(imagePath)
.signature(new StringSignature(yourVersion))
.into(ImageView);
Just pass new StringSignature(System.currentTimeMillis()+"") to the signature so that it will load the image from network every time

You could also try setting Signatures
As per the glide documentation on caching
Try this
Glide.with(context)
.load(url) .
signature(new StringSignature(System.currentTimeMillis()))
.into(imageView);
Check here for more details

Well everyone thanks a lot for help :)
I resolved this problem by disabling cache of volley library that was causing the issue but anyway thanks for help :)
//disabling caching for url
AppController.getInstance().getRequestQueue().getCache().remove(url);

How to properly ask for permissions on Runtime?

Hi im making an application using Android Studios the requires 3 permissions in total
CALL_PHONE, READ_CONTACTS, RECORD_AUDIO.
im kinda very new to development and thats why my coding is a bit sloppy(no kidding), when I run the app it doesnt asks for the permission and doesnt work but if i manually go to setting and grant the permissions it works fine
Im using fragments and writing the code in the fragment class is that wrong or should i write this code in my mainActivity.java
Im attaching both please look at my code and how can I improve it
If I have to work from the scratch im ok with it.
DialerActivity.java:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
public class DialerActivity extends FragmentActivity {
private static final String FRAGMENT_TAG_DIALER = "fragment:dialer";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dialer);
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = (DialerFragment) fm.findFragmentByTag(FRAGMENT_TAG_DIALER);
if(fragment == null){
fragment = new DialerFragment();
fm.beginTransaction()
.add(R.id.fragment_container,fragment, FRAGMENT_TAG_DIALER)
.commit();
}
}
}
DialerFragmnet.java:
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;;
import android.support.v4.content.ContextCompat;
public class DialerFragment extends Fragment {
private EditText mPhoneField;
private Button mDialButton;
//Requesting Permissions on Runtime.
final private int REQUEST_CODE_ASK_PERMISSIONS=0;
private void InitiateCall(){
int hasCallPermission = ContextCompat.checkSelfPermission(getActivity(),Manifest.permission.READ_PHONE_STATE);
if (hasCallPermission != PackageManager.PERMISSION_GRANTED){
requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE},
REQUEST_CODE_ASK_PERMISSIONS);
return;
}
InitiateCall();
}
#Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults ){
switch (requestCode){
case REQUEST_CODE_ASK_PERMISSIONS:
if (grantResults[0]==PackageManager.PERMISSION_GRANTED){
//YAY! PERMISSION GRANTED
InitiateCall();
}else{
//GD! PERMISSION DENIED
Toast.makeText(getActivity(), R.string.permission_denied, Toast.LENGTH_SHORT).show();
}
break;
default:
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState){
View v=inflater.inflate(R.layout.fragment_dialer,container,false);
mPhoneField=(EditText) v.findViewById(R.id.input_pno);
mDialButton=(Button) v.findViewById(R.id.dial_button);
mDialButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
try{
if (mPhoneField != null && (mPhoneField.getText().length()==10||mPhoneField.getText().length()==11)){
startActivity(new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + mPhoneField.getText())));
}
else if(mPhoneField != null && mPhoneField.getText().length()==0){
Toast.makeText(getActivity(),R.string.no_number_toast,Toast.LENGTH_SHORT).show();
}
else if(mPhoneField !=null && mPhoneField.getText().length()<10){
Toast.makeText(getActivity(),R.string.wrong_number_toast,Toast.LENGTH_SHORT).show();
}
} catch (Exception e){
Log.e("DialerAppActivity","error: " + e.getMessage(),e);//Runtime error will be logged
}
}
});
return v;
}
}

You actually never call your method that ask the permission.
Your method : InitiateCall should not call itself, because it'll create an infiniteLoop. So you should modify it to be this way:
private void InitiateCall(){
int hasCallPermission = ContextCompat.checkSelfPermission(getActivity(),Manifest.permission.READ_PHONE_STATE);
if (hasCallPermission != PackageManager.PERMISSION_GRANTED){
requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE},
REQUEST_CODE_ASK_PERMISSIONS);
return;
}
}
and you can call InitiateCall at the end of the onCreateView.