Very slow scroll, context menu and crash by ProgressDialog

Very slow scroll, context menu and crash by ProgressDialog - java

i have many problem with this code
ApplicationAdapter
import java.util.List;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class ApplicationAdapter extends ArrayAdapter<ApplicationInfo> {
private List<ApplicationInfo> appsList = null;
private Context context;
private PackageManager packageManager;
public ApplicationAdapter(Context context, int textViewResourceId,
List<ApplicationInfo> appsList) {
super(context, textViewResourceId, appsList);
this.context = context;
this.appsList = appsList;
packageManager = context.getPackageManager();
}
#Override
public int getCount() {
return ((null != appsList) ? appsList.size() : 0);
}
#Override
public ApplicationInfo getItem(int position) {
return ((null != appsList) ? appsList.get(position) : null);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (null == view) {
LayoutInflater layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = layoutInflater.inflate(R.layout.snippet_list_row, null);
}
ApplicationInfo data = appsList.get(position);
if (null != data) {
TextView appName = (TextView) view.findViewById(R.id.app_name);
TextView packageName = (TextView) view.findViewById(R.id.app_paackage);
ImageView iconview = (ImageView) view.findViewById(R.id.app_icon);
appName.setText(data.loadLabel(packageManager));
packageName.setText(data.packageName);
iconview.setImageDrawable(data.loadIcon(packageManager));
}
return view;
}
};
MainActivity
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.Button;
import android.widget.ListView;
public class MainActivity extends ListActivity {
private PackageManager packageManager = null;
private List<ApplicationInfo> applist = null;
private ApplicationAdapter listadaptor = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_eclair);
packageManager = getPackageManager();
new LoadApplications().execute();
Button bottone1 = (Button)findViewById(R.id.button1);
bottone1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
new LoadApplications().execute();
}
});};
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
ApplicationInfo app = applist.get(position);
/*
try {
Intent intent = packageManager
.getLaunchIntentForPackage(app.packageName);
if (null != intent) {
startActivity(intent);
}
} catch (ActivityNotFoundException e) {
Toast.makeText(Activity_Eclair.this, e.getMessage(),
Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(Activity_Eclair.this, e.getMessage(),
Toast.LENGTH_LONG).show();
}
*/
Uri packageUri = Uri.parse("package:"+app.packageName);
Intent uninstallIntent =
new Intent(Intent.ACTION_DELETE, packageUri);
startActivity(uninstallIntent);
}
private List<ApplicationInfo> checkForLaunchIntent(List<ApplicationInfo> list) {
ArrayList<ApplicationInfo> applist = new ArrayList<ApplicationInfo>();
for (ApplicationInfo info : list) {
try {
if (null != packageManager.getLaunchIntentForPackage(info.packageName)) {
applist.add(info);
}
} catch (Exception e) {
e.printStackTrace();
}
}
return applist;
}
private class LoadApplications extends AsyncTask<Void, Void, Void> {
public ProgressDialog progress = null;
#Override
protected Void doInBackground(Void... params) {
applist = checkForLaunchIntent(packageManager.getInstalledApplications(PackageManager.GET_META_DATA));
listadaptor = new ApplicationAdapter(Activity_Eclair.this,
R.layout.snippet_list_row, applist);
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
}
protected void onDestroy() {
if(progress!=null)
if(progress.isShowing()){
progress.dismiss();
}
}
#Override
protected void onPostExecute(Void result) {
setListAdapter(listadaptor);
progress.dismiss();
super.onPostExecute(result);
}
#Override
protected void onPreExecute() {
progress = ProgressDialog.show(Activity_Eclair.this, null,
"Caricamento applicazioni in corso...");
super.onPreExecute();
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
}
First, if you are viewing the ProgressDialog I rotate the phone, the application crashes even though I put the onDestroy method. Second, the scroll is very slow, you have no idea on how I can improve it and make it fluid? Third and last thing, I just can not enter a ContextMenu, I really did many attempts but I always get errors. Do you know help me?

When you switch orientations, Android will create a new View. You're probably getting crashes because your background thread is trying to change the state on the old one. (It may also be having trouble because your background thread isn't on the UI thread)
Post error from logcat

Related

Attempt to invoke virtual method (null object reference)

Currently, I'm developing a media player, and I want hide a element when audio finishes. But when it happens, the app crash with this error: Attempt to invoke virtual method 'void android.widget.LinearLayout.setVisibility(int)' on a null object reference. Check my current code:
meplayer.java
package etes.xddda.music;
import android.app.Activity;
import android.content.Context;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.Toast;
public class meplayer extends Activity {
public static MediaPlayer mediaPlayer;
public LinearLayout menu_dialog;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
menu_dialog = findViewById(R.id.menu_dialog);
}
public void initAudio(final Context context, final String url) {
if (mediaPlayer == null) {
mediaPlayer = MediaPlayer.create(context, Uri.parse(url));
}
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
public LinearLayout menu_dialog;
#Override
public void onCompletion(MediaPlayer mp) {
//Toast.makeText(context, "TEST", Toast.LENGTH_LONG).show();
killMediaPlayer();
menu_dialog.setVisibility(View.GONE);
}
});
mediaPlayer.start();
}
private void killMediaPlayer() {
if (mediaPlayer != null) {
try {
mediaPlayer.reset();
mediaPlayer.release();
mediaPlayer = null;
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
RecyclerViewAdapter
package etes.xddda.music;
import android.app.Dialog;
import android.content.Context;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.media.MediaPlayer;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.List;
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> implements View.OnClickListener{
Context mContext;
List<mList> mData;
Dialog myDialog;
private MediaPlayer mediaPlayer;
private int playbackPosition=0;
meplayer media;
private LinearLayout menu_dialog;
public RecyclerViewAdapter(Context mContext, List<mList> mData) {
this.mContext = mContext;
this.mData = mData;
}
public void onClick(View view) {
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v;
v = LayoutInflater.from(mContext).inflate(R.layout.item_list, parent, false);
final MyViewHolder vHolder = new MyViewHolder(v);
// Dialog ini
myDialog = new Dialog(mContext);
myDialog.setContentView(R.layout.dialog);
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
vHolder.item_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
TextView dialog_name_tv = (TextView) myDialog.findViewById(R.id.dialog_name_id);
TextView dialog_phone_tv = (TextView) myDialog.findViewById(R.id.dialog_author_id);
ImageView dialog_contact_img = (ImageView) myDialog.findViewById(R.id.dialog_img);
dialog_name_tv.setText(mData.get(vHolder.getAdapterPosition()).getName());
dialog_phone_tv.setText(mData.get(vHolder.getAdapterPosition()).getPhone());
dialog_contact_img.setImageResource(mData.get(vHolder.getAdapterPosition()).getPhoto());
//Toast.makeText(mContext, "Test click "+String.valueOf(vHolder.getAdapterPosition()), Toast.LENGTH_SHORT).show();
myDialog.show();
}
});
vHolder.menu_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
menu_dialog = v.getRootView().findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(v.VISIBLE);
media = new meplayer();
media.initAudio(v.getContext(), mData.get(vHolder.getAdapterPosition()).getURL());
MainActivity.setMargins(v.getRootView().findViewById(R.id.viewpager_id), 0,0,0,100);
}
});
return vHolder;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.tv_name.setText(mData.get(position).getName());
holder.tv_author.setText(mData.get(position).getPhone());
holder.img.setImageResource(mData.get(position).getPhoto());
}
#Override
public int getItemCount() {
return mData.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
private ImageButton item_play;
private LinearLayout menu_play;
private TextView tv_name;
private TextView tv_author;
private TextView tv_url;
private ImageView img;
public MyViewHolder(View itemView) {
super(itemView);
item_play = itemView.findViewById(R.id.info_id);
menu_play = itemView.findViewById(R.id.list_item_id);
tv_name = (TextView) itemView.findViewById(R.id.name_list);
tv_author = (TextView) itemView.findViewById(R.id.author_list);
img = (ImageView) itemView.findViewById(R.id.img_contact);
}
}
}
fragmentList
package etes.xddda.music;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class fragmentList extends Fragment {
View v;
private RecyclerView myrecyclerview;
private List<mList> lstContact;
private String URL_JSON = "https://pastebin.com/raw/fG3zd40U";
private JsonArrayRequest ArrayRequest;
private RequestQueue requestQueue ;
public fragmentList() {
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
v = inflater.inflate(R.layout.list_fragment,container,false);
myrecyclerview = (RecyclerView) v.findViewById(R.id.list_recyclerview);
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getContext(), lstContact);
myrecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
myrecyclerview.setAdapter(recyclerViewAdapter);
return v;
}
#Override
public void onCreate(#Nullable Bundle savedInstaceState) {
super.onCreate(savedInstaceState);
_JSONcall();
}
public void _JSONcall() {
lstContact = new ArrayList<>();
ArrayRequest = new JsonArrayRequest(URL_JSON, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
JSONObject jsonObject = null;
for (int i = 0 ; i<response.length();i++) {
try {
jsonObject = response.getJSONObject(i);
lstContact.add(new mList(jsonObject.getString("name"), jsonObject.getString("description"), jsonObject.getString("link"), R.drawable.ic_play_circle_filled_black_24dp));
}
catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getActivity(), "Error 1!",
Toast.LENGTH_LONG).show();
}
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(), "Error 3!",
Toast.LENGTH_LONG).show();
}
});
requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());
requestQueue.add(ArrayRequest);
}
}
MainActivity
package etes.xddda.music;
import android.annotation.SuppressLint;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.LinearLayout;
public class MainActivity extends AppCompatActivity {
private DrawerLayout nDrawerLayout;
private ActionBarDrawerToggle mToggle;
private TabLayout tabLayout;
private ViewPager viewPager;
private viewPagerAdapter adapter;
public LinearLayout menu_dialog;
private String player_status = "playing";
private ImageButton player_img;
#SuppressLint("RestrictedApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
nDrawerLayout = findViewById(R.id.drawer);
menu_dialog = findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(View.GONE);
player_img = findViewById(R.id.playorpause);
player_img.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//setMargins(viewPager, 0,0,0,110);
if (player_status == "playing") {
player_img.setImageResource(R.drawable.ic_play_arrow_black_24dp);
meplayer.pauseAudio();
player_status = "paused";
} else {
player_img.setImageResource(R.drawable.ic_pause_black_24dp);
meplayer.startAudio();
player_status = "playing";
}
}
});
//menu_dialog.setLayoutParams(new LinearLayout.LayoutParams(0, 0));
mToggle = new ActionBarDrawerToggle(this, nDrawerLayout, R.string.open, R.string.close);
nDrawerLayout.addDrawerListener(mToggle);
getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
tabLayout = findViewById(R.id.tablayout_id);
viewPager = findViewById(R.id.viewpager_id);
//viewPager.setLayoutParams(new ViewPager.LayoutParams(0, 0));
//setMarginBottom(viewPager, 0);
setMargins(viewPager, 0,0,0,0);
adapter = new viewPagerAdapter(getSupportFragmentManager());
//Add fragments here
adapter.addFragment(new fragmentList(), ""); //Lista de música
adapter.addFragment(new fragmentFrequent(), ""); //Frequentes
adapter.addFragment(new fragmentPlayList(), ""); //Playlist
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.ic_music_note_black_24dp); //Lista de música
tabLayout.getTabAt(1).setIcon(R.drawable.ic_filter_list_black_24dp); // Frequentes
tabLayout.getTabAt(2).setIcon(R.drawable.ic_queue_music_black_24dp); // Playlist
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mToggle.syncState();
}
public static void setMargins (View v, int l, int t, int r, int b) {
if (v.getLayoutParams() instanceof ViewGroup.MarginLayoutParams) {
ViewGroup.MarginLayoutParams p = (ViewGroup.MarginLayoutParams) v.getLayoutParams();
p.setMargins(l, t, r, b);
v.requestLayout();
}
}
}
mList
package etes.xddda.music;
public class mList {
private String Name;
private String Author;
private String URL;
private int Photo;
public mList() {
}
public mList(String name, String phone, String url, int photo) {
Name = name;
Author = phone;
URL = url;
Photo = photo;
}
//Get User
public String getName() {
return Name;
}
public String getPhone() {
return Author;
}
public String getURL() {
return URL;
}
public int getPhoto() {
return Photo;
}
//Setter
public void setName(String name) {
Name = name;
}
public void setPhone(String phone) {
Author = phone;
}
public void setURL(String url) {
URL = url;
}
public void setPhoto(int photo) {
Photo = photo;
}
}
There are no errors in this script, the app just crash when audio finishes. The problem is related to line menu_dialog.setVisibility(View.GONE); and I have already defined menu_dialog in onCreate. So, can you help me?
P.S.: menu_dialog belongs to activity_main.xml
Thank you!

Remove the local variable menu_dialog that you have defined inside the OnCompletionListener:
package etes.xddda.music;
import android.app.Activity;
import android.content.Context;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.Toast;
public class meplayer extends Activity {
public static MediaPlayer mediaPlayer;
public LinearLayout menu_dialog;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
menu_dialog = findViewById(R.id.menu_dialog);
}
public void initAudio(final Context context, final String url) {
if (mediaPlayer == null) {
mediaPlayer = MediaPlayer.create(context, Uri.parse(url));
}
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
//public LinearLayout menu_dialog; REMOVE THIS
#Override
public void onCompletion(MediaPlayer mp) {
//Toast.makeText(context, "TEST", Toast.LENGTH_LONG).show();
killMediaPlayer();
menu_dialog.setVisibility(View.GONE);
}
});
mediaPlayer.start();
}
private void killMediaPlayer() {
if (mediaPlayer != null) {
try {
mediaPlayer.reset();
mediaPlayer.release();
mediaPlayer = null;
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

Attempt to invoke virtual method [Null object reference] [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 4 years ago.
I'm spending the last 5 days trying solve this problem. I really do not have any idea about how to solve it. I'm getting Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference. Check my code:
RecyclerView.java
package etes.xdda.music;
import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.media.MediaPlayer;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.List;
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> implements View.OnClickListener{
Context mContext;
List<mList> mData;
Dialog myDialog;
private MediaPlayer mediaPlayer;
private int playbackPosition=0;
private LinearLayout menu_dialog;
public RecyclerViewAdapter(Context mContext, List<mList> mData) {
this.mContext = mContext;
this.mData = mData;
}
public void onClick(View view) {
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v;
v = LayoutInflater.from(mContext).inflate(R.layout.item_list, parent, false);
final MyViewHolder vHolder = new MyViewHolder(v);
// Dialog ini
myDialog = new Dialog(mContext);
myDialog.setContentView(R.layout.dialog);
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
vHolder.item_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
TextView dialog_name_tv = (TextView) myDialog.findViewById(R.id.dialog_name_id);
TextView dialog_phone_tv = (TextView) myDialog.findViewById(R.id.dialog_author_id);
ImageView dialog_contact_img = (ImageView) myDialog.findViewById(R.id.dialog_img);
dialog_name_tv.setText(mData.get(vHolder.getAdapterPosition()).getName());
dialog_phone_tv.setText(mData.get(vHolder.getAdapterPosition()).getPhone());
dialog_contact_img.setImageResource(mData.get(vHolder.getAdapterPosition()).getPhoto());
//Toast.makeText(mContext, "Test click "+String.valueOf(vHolder.getAdapterPosition()), Toast.LENGTH_SHORT).show();
myDialog.show();
}
});
vHolder.menu_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
menu_dialog = v.getRootView().findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(v.VISIBLE);
MainActivity a = new MainActivity();
a.initAudio(v.getContext(), mData.get(vHolder.getAdapterPosition()).getURL());
MainActivity.setMargins(v.getRootView().findViewById(R.id.viewpager_id), 0,0,0,100);
}
});
return vHolder;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.tv_name.setText(mData.get(position).getName());
holder.tv_author.setText(mData.get(position).getPhone());
holder.img.setImageResource(mData.get(position).getPhoto());
}
#Override
public int getItemCount() {
return mData.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
private ImageButton item_play;
private LinearLayout menu_play;
private TextView tv_name;
private TextView tv_author;
private TextView tv_url;
private ImageView img;
public MyViewHolder(View itemView) {
super(itemView);
item_play = itemView.findViewById(R.id.info_id);
menu_play = itemView.findViewById(R.id.list_item_id);
tv_name = (TextView) itemView.findViewById(R.id.name_list);
tv_author = (TextView) itemView.findViewById(R.id.author_list);
img = (ImageView) itemView.findViewById(R.id.img_contact);
}
}
}
Note that I'm invoking MainActivity.java in this part:
vHolder.menu_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
menu_dialog = v.getRootView().findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(v.VISIBLE);
MainActivity a = new MainActivity();
a.initAudio(v.getContext(), mData.get(vHolder.getAdapterPosition()).getURL());
MainActivity.setMargins(v.getRootView().findViewById(R.id.viewpager_id), 0,0,0,100);
}
});
And here's my MainActivity.java
package etes.xdda.music;
import android.annotation.SuppressLint;
import android.content.Context;
import android.media.MediaPlayer;
import android.net.Uri;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.LinearLayout;
public class MainActivity extends AppCompatActivity {
private DrawerLayout nDrawerLayout;
private ActionBarDrawerToggle mToggle;
private TabLayout tabLayout;
private ViewPager viewPager;
private viewPagerAdapter adapter;
public LinearLayout menu_dialog;
private String player_status = "playing";
private ImageButton player_img;
private static MediaPlayer mediaPlayer;
#SuppressLint("RestrictedApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
nDrawerLayout = findViewById(R.id.drawer);
menu_dialog = findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(View.GONE);
player_img = findViewById(R.id.playorpause);
player_img.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//setMargins(viewPager, 0,0,0,110);
if (player_status == "playing") {
player_img.setImageResource(R.drawable.ic_play_arrow_black_24dp);
meplayer.pauseAudio();
player_status = "paused";
} else {
player_img.setImageResource(R.drawable.ic_pause_black_24dp);
meplayer.startAudio();
player_status = "playing";
}
}
});
//menu_dialog.setLayoutParams(new LinearLayout.LayoutParams(0, 0));
mToggle = new ActionBarDrawerToggle(this, nDrawerLayout, R.string.open, R.string.close);
nDrawerLayout.addDrawerListener(mToggle);
getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
tabLayout = findViewById(R.id.tablayout_id);
viewPager = findViewById(R.id.viewpager_id);
//viewPager.setLayoutParams(new ViewPager.LayoutParams(0, 0));
//setMarginBottom(viewPager, 0);
setMargins(viewPager, 0,0,0,0);
adapter = new viewPagerAdapter(getSupportFragmentManager());
//Add fragments here
adapter.addFragment(new fragmentList(), ""); //Lista de música
adapter.addFragment(new fragmentFrequent(), ""); //Frequentes
adapter.addFragment(new fragmentPlayList(), ""); //Playlist
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.ic_music_note_black_24dp); //Lista de música
tabLayout.getTabAt(1).setIcon(R.drawable.ic_filter_list_black_24dp); // Frequentes
tabLayout.getTabAt(2).setIcon(R.drawable.ic_queue_music_black_24dp); // Playlist
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mToggle.syncState();
}
public static void setMargins (View v, int l, int t, int r, int b) {
if (v.getLayoutParams() instanceof ViewGroup.MarginLayoutParams) {
ViewGroup.MarginLayoutParams p = (ViewGroup.MarginLayoutParams) v.getLayoutParams();
p.setMargins(l, t, r, b);
v.requestLayout();
}
}
public void initAudio(final Context context, final String url) {
if (mediaPlayer == null) {
mediaPlayer = MediaPlayer.create(context, Uri.parse(url));
}
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
#Override
public void onCompletion(MediaPlayer mp) {
//Toast.makeText(context, "TEST", Toast.LENGTH_LONG).show();
killMediaPlayer();
updateLayout();
}
});
mediaPlayer.start();
}
private static void killMediaPlayer() {
if (mediaPlayer != null) {
try {
mediaPlayer.reset();
mediaPlayer.release();
mediaPlayer = null;
} catch (Exception e) {
e.printStackTrace();
}
}
}
private void updateLayout() {
try {
menu_dialog = findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(View.GONE);
} catch (Exception e) {
e.printStackTrace();
}
}
And the part of code that is giving crash is this:
private void updateLayout() {
try {
menu_dialog = findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(View.GONE);
} catch (Exception e) {
e.printStackTrace();
}
}
#edit: I have added this piece of code, I don't know if can help
fragmentList.java
package etes.xdda.music;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class fragmentList extends Fragment {
View v;
private RecyclerView myrecyclerview;
private List<mList> lstContact;
private String URL_JSON = "https://pastebin.com/raw/fG3zd40U";
private JsonArrayRequest ArrayRequest;
private RequestQueue requestQueue ;
MainActivity activity;
public fragmentList() {
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
v = inflater.inflate(R.layout.list_fragment,container,false);
myrecyclerview = (RecyclerView) v.findViewById(R.id.list_recyclerview);
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(activity, lstContact);
myrecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
myrecyclerview.setAdapter(recyclerViewAdapter);
return v;
}
#Override
public void onCreate(#Nullable Bundle savedInstaceState) {
super.onCreate(savedInstaceState);
_JSONcall();
}
public void _JSONcall() {
lstContact = new ArrayList<>();
ArrayRequest = new JsonArrayRequest(URL_JSON, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
JSONObject jsonObject = null;
for (int i = 0 ; i<response.length();i++) {
try {
jsonObject = response.getJSONObject(i);
lstContact.add(new mList(jsonObject.getString("name"), jsonObject.getString("description"), jsonObject.getString("link"), R.drawable.ic_play_circle_filled_black_24dp));
}
catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getActivity(), "Error 1!",
Toast.LENGTH_LONG).show();
}
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(), "Error 3!",
Toast.LENGTH_LONG).show();
}
});
requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());
requestQueue.add(ArrayRequest);
}
}
Please, help me, I have no more ideas about what I should do. Thank you

Just taking a look at your code, it looks like you are doing many things wrong. Such as this line
MainActivity a = new MainActivity();
You can't instantiate lifecycle components like Services, Activities, Fragments etc this way. Android provides you these components when you call start methods etc. The activity that is created as a result of the above line doesn't go through the lifecycle calls that an activity that is started via using startActivity. As a result, the setContentView of the activity is never called and you get this error. You have to remove this line and implement this properly and the error will go away.
Also just to add, you are actually creating a new instance of the activity when one is already running when you need to call the methods on the old instance that was started.
Edit: Try like this.
MainActivity activity;
List<mList> mData;
Dialog myDialog;
private MediaPlayer mediaPlayer;
private int playbackPosition=0;
private LinearLayout menu_dialog;
public RecyclerViewAdapter(MainActivity activity, List<mList> mData) {
this.activity = activity;
this.mData = mData;
}
And then
vHolder.menu_play.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
menu_dialog = v.getRootView().findViewById(R.id.menu_dialog);
menu_dialog.setVisibility(v.VISIBLE);
activity.initAudio(v.getContext(), mData.get(vHolder.getAdapterPosition()).getURL());
activity.setMargins(v.getRootView().findViewById(R.id.viewpager_id), 0,0,0,100);
}
});
Also remove static from the main activity functions

How to add a listview item to a whole other listview

So in my android app, I have two scrollable tabs which each contain Listview using a Fragment. One a list of apps and the other is blank. What I am aiming to do is add a plus button in place of where my checkbox is and duplicate that item in the other listview which is blank.
I have done research on this, but I have not found any successful examples on how to implement this.
Android - Add an item from one ListView to another ListView?
Here is my fragment that returns the apps
package com.spicycurryman.getdisciplined10.app;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageItemInfo;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import com.ibc.android.demo.appslist.app.ApkAdapter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class InstalledAppActivity extends Fragment
implements OnItemClickListener {
PackageManager packageManager;
ListView apkList;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
View rootView = inflater.inflate(R.layout.user_installed, container, false);
packageManager = getActivity().getPackageManager();
/*To filter out System apps*/
apkList = (ListView) rootView.findViewById(R.id.applist);
new LoadApplications(getActivity().getApplicationContext()).execute();
return rootView;
}
/**
* Return whether the given PackageInfo represents a system package or not.
* User-installed packages (Market or otherwise) should not be denoted as
* system packages.
*
* #param pkgInfo
* #return boolean
*/
private boolean isSystemPackage(PackageInfo pkgInfo) {
return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) ? true
: false;
}
private boolean isSystemPackage1(PackageInfo pkgInfo) {
return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP) != 0) ? false
: true;
}
// Don't need in Fragment
/*#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.block, menu);
// super.onCreateOptionsMenu(menu,inflater);
}*/
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
}
private class LoadApplications extends AsyncTask<Void, Void, Void> {
Context mContext;
private ProgressDialog pDialog;
List<PackageInfo> packageList1 = new ArrayList<PackageInfo>();
public LoadApplications(Context context){
Context mContext = context;
}
#Override
protected Void doInBackground(Void... params) {
List<PackageInfo> packageList = packageManager
.getInstalledPackages(PackageManager.GET_PERMISSIONS);
/* List<ApplicationInfo> list = mContext.getPackageManager().getInstalledApplications(PackageManager.GET_UNINSTALLED_PACKAGES);
for(int n = 0;n<list.size();n++){
if ((list.get(n).flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP))
}*/
for(PackageInfo pi : packageList) {
boolean b = isSystemPackage(pi);
boolean c = isSystemPackage1(pi);
if(!b || !c ) {
packageList1.add(pi);
}
}
//sort by application name
final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);
Collections.sort(packageList1, new Comparator<PackageInfo>() {
#Override
public int compare(PackageInfo lhs, PackageInfo rhs) {
return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
}
});
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
}
#Override
protected void onPreExecute() {
pDialog = new ProgressDialog(InstalledAppActivity.this.getActivity());
pDialog.setMessage("Loading your apps...");
pDialog.show();
}
#Override
protected void onPostExecute(Void result) {
apkList.setAdapter(new ApkAdapter(getActivity(), packageList1, packageManager));
if (pDialog.isShowing()){
pDialog.dismiss();
}
super.onPostExecute(result);
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
}
And here is my adapter class:
package com.ibc.android.demo.appslist.app;
import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
import com.spicycurryman.getdisciplined10.app.R;
import java.util.List;
public class ApkAdapter extends BaseAdapter {
List<PackageInfo> packageList;
Activity context;
PackageManager packageManager;
boolean[] itemChecked;
public ApkAdapter(Activity context, List<PackageInfo> packageList,
PackageManager packageManager) {
super();
this.context = context;
this.packageList = packageList;
this.packageManager = packageManager;
itemChecked = new boolean[packageList.size()];
}
private class ViewHolder {
TextView apkName;
CheckBox ck1;
}
public int getCount() {
return packageList.size();
}
public Object getItem(int position) {
return packageList.get(position);
}
public long getItemId(int position) {
return 0;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder holder;
LayoutInflater inflater = context.getLayoutInflater();
if (convertView == null) {
convertView = inflater.inflate(R.layout.installed_apps, null);
holder = new ViewHolder();
holder.apkName = (TextView) convertView
.findViewById(R.id.appname);
holder.ck1 = (CheckBox) convertView
.findViewById(R.id.checkBox1);
convertView.setTag(holder);
//holder.ck1.setTag(packageList.get(position));
} else {
holder = (ViewHolder) convertView.getTag();
}
// ViewHolder holder = (ViewHolder) convertView.getTag();
PackageInfo packageInfo = (PackageInfo) getItem(position);
Drawable appIcon = packageManager
.getApplicationIcon(packageInfo.applicationInfo);
String appName = packageManager.getApplicationLabel(
packageInfo.applicationInfo).toString();
appIcon.setBounds(0, 0, 75, 75);
holder.apkName.setCompoundDrawables(appIcon, null, null, null);
holder.apkName.setCompoundDrawablePadding(15);
holder.apkName.setText(appName);
holder.ck1.setChecked(false);
if (itemChecked[position])
holder.ck1.setChecked(true);
else
holder.ck1.setChecked(false);
holder.ck1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (holder.ck1.isChecked())
itemChecked[position] = true;
else
itemChecked[position] = false;
}
});
return convertView;
}
}
How would I go about achieving this?

So what you are doing is, you are populating a listview of installed apps using package manager. Add a plus button in place of the checkbox. Now get installed apps similar to this -
List<PackageInfo> packageList1 = packageManager.getInstalledPackages(0);
final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);
Collections.sort(packageList1, new Comparator<PackageInfo>() {
#Override
public int compare(PackageInfo lhs, PackageInfo rhs) {
return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
}
});
for (int i = 0; i < packageList1.size(); i++) {
PackageInfo PackInfo = packageList1.get(i);
if (((PackInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) != true) {
//Add to adapter
}
}
}
Now, create a public string array in the activity which is holding the tabs. When you click on the plus button add the packagename to the array.
Now on the other tab use the same adapter, but here before adding it to the adapter check if it is found in the string array using the index. Something like -
List<PackageInfo> packageList1 = packageManager.getInstalledPackages(0);
final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);
Collections.sort(packageList1, new Comparator<PackageInfo>() {
#Override
public int compare(PackageInfo lhs, PackageInfo rhs) {
return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
}
});
for (int i = 0; i < packageList1.size(); i++) {
PackageInfo PackInfo = packageList1.get(i);
if (((PackInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) != true) {
if (Mainactivity.array contains String PackageName= PackInfo.packageName)
{
//Add to adapter
}
}
}
}
To persist the selected apps, add their package name to shared_preferences.
edit :
In your fragment's LoadApplications class, you retrieve a list of installed apps. On the second fragment use the same code, but just add one more condition
for(PackageInfo pi : packageList) {
boolean b = isSystemPackage(pi);
boolean c = isSystemPackage1(pi);
if(!b || !c ) {
if (array contains packagename){
packageList1.add(pi);
}
}

List<UserApps> packageListBlocked = new ArrayList<UserApps>();
holder.ck1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if (holder.ck1.isChecked())
itemChecked[position] = true;
packageListBlocked.add(packageList.get(position));
else
itemChecked[position] = false;
}
});
ArrayList can hold duplicate data, so be cautious while adding.
Now you have all checkedItems in packageListBlocked pass it on to next tab and set data, make sure you call adapter.notifyDataSetChanged();

ApplicationAdapter error when trying to get installed apps

I am have scrollable tabs in my action bar and in one of those tabs I am trying to get a list of user installed apps and used system apps, like Flipoard, youtube, messaging etc. (eventually in alphabetical order)
I am trying to follow these, but I am having some errors implementing it because I am using fragments.
How to get a list of installed android applications and pick one to run
http://javatechig.com/android/how-to-get-list-of-installed-apps-in-android
http://techblogon.com/get-installed-applications-list-android-example/
This is what I have for my Fragment:
package com.spicycurryman.getdisciplined10.app;
import android.app.ProgressDialog;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageItemInfo;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import com.ibc.android.demo.appslist.app.ApplicationAdapter;
import java.util.ArrayList;
import java.util.List;
public class InstalledAppActivity extends Fragment
implements OnItemClickListener {
PackageManager packageManager;
ListView apkList;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
View rootView = inflater.inflate(R.layout.user_installed, container, false);
packageManager = getActivity().getPackageManager();
/*To filter out System apps*/
apkList = (ListView) rootView.findViewById(R.id.applist);
new LoadApplications().execute();
return rootView;
}
/**
* Return whether the given PackageInfo represents a system package or not.
* User-installed packages (Market or otherwise) should not be denoted as
* system packages.
*
* #parampkgInfo
* #return boolean
*/
/* private boolean isSystemPackage(ApplicationInfo pkgInfo) {
return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) ? true
: false;
}*/
// Don't need in Fragment
/*#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.block, menu);
// super.onCreateOptionsMenu(menu,inflater);
}*/
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
}
private class LoadApplications extends AsyncTask<Void, Void, Void> {
private ProgressDialog pDialog;
List<ApplicationInfo> packageList1 = new ArrayList<ApplicationInfo>();
#Override
protected Void doInBackground(Void... params) {
List<ApplicationInfo> packages = packageManager.getInstalledApplications(PackageManager.GET_META_DATA);
for(ApplicationInfo pi : packages) {
packageList1.add(pi);
}
//sort by application name
final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);
/*Collections.sort(packageList1, new Comparator<PackageInfo>() {
#Override
public int compare(PackageInfo lhs, PackageInfo rhs) {
return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
}
});*/
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
}
#Override
protected void onPreExecute() {
pDialog = new ProgressDialog(InstalledAppActivity.this.getActivity());
pDialog.setMessage("Loading your apps...");
pDialog.show();
}
#Override
protected void onPostExecute(Void result) {
apkList.setAdapter(new ApplicationAdapter(getActivity(), packageList1, packageManager));
if (pDialog.isShowing()){
pDialog.dismiss();
}
super.onPostExecute(result);
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
}
and this here is my ArrayAdapter class:
package com.ibc.android.demo.appslist.app;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
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 com.spicycurryman.getdisciplined10.app.R;
import java.util.List;
public class ApplicationAdapter extends ArrayAdapter<ApplicationInfo> {
private List<ApplicationInfo> appsList = null;
private Context context;
private PackageManager packageManager;
public ApplicationAdapter(Context context, List<ApplicationInfo> textViewResourceId,
PackageManager appsList) {
super(context, textViewResourceId, appsList);
this.context = context;
this.appsList = (List<ApplicationInfo>) appsList;
packageManager = context.getPackageManager();
}
#Override
public int getCount() {
return ((null != appsList) ? appsList.size() : 0);
}
#Override
public ApplicationInfo getItem(int position) {
return ((null != appsList) ? appsList.get(position) : null);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (null == view) {
LayoutInflater layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = layoutInflater.inflate(R.layout.snippet_list_row, null);
}
ApplicationInfo data = appsList.get(position);
if (null != data) {
TextView appName = (TextView) view.findViewById(R.id.app_name);
TextView packageName = (TextView) view.findViewById(R.id.app_package);
ImageView iconview = (ImageView) view.findViewById(R.id.app_icon);
appName.setText(data.loadLabel(packageManager));
packageName.setText(data.packageName);
iconview.setImageDrawable(data.loadIcon(packageManager));
}
return view;
}
};
This is the current error I am getting.
I am not sure what I should do to resolve this error and successfully get a list of user installed and used system apps in alphabetical order in all in a fragment.
What can be done about my approach and how can I achieve this?

One of the arguments you're passing to the constructor of the super class, that is an ArrayAdapter, does not match with any of the ArrayAdapter's constructors.
I believe that argument is the the PackageManager appsList, you should instead pass a List<T> appsList to match the constructor defined here.

Optimization of code for more speed [closed]

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This question does not appear to be about programming within the scope defined in the help center.
Closed 9 years ago.
Improve this question
i have this code and the scroll is slow
ApplicationAdapter
import java.util.List;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class ApplicationAdapter extends ArrayAdapter<ApplicationInfo> {
private List<ApplicationInfo> appsList = null;
private Context context;
private PackageManager packageManager;
public ApplicationAdapter(Context context, int textViewResourceId,
List<ApplicationInfo> appsList) {
super(context, textViewResourceId, appsList);
this.context = context;
this.appsList = appsList;
packageManager = context.getPackageManager();
}
#Override
public int getCount() {
return ((null != appsList) ? appsList.size() : 0);
}
#Override
public ApplicationInfo getItem(int position) {
return ((null != appsList) ? appsList.get(position) : null);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (null == view) {
LayoutInflater layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = layoutInflater.inflate(R.layout.snippet_list_row, null);
}
ApplicationInfo data = appsList.get(position);
if (null != data) {
TextView appName = (TextView) view.findViewById(R.id.app_name);
TextView packageName = (TextView) view.findViewById(R.id.app_paackage);
ImageView iconview = (ImageView) view.findViewById(R.id.app_icon);
appName.setText(data.loadLabel(packageManager));
packageName.setText(data.packageName);
iconview.setImageDrawable(data.loadIcon(packageManager));
}
return view;
}
};
MainActivity
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.Button;
import android.widget.ListView;
public class MainActivity extends ListActivity {
private PackageManager packageManager = null;
private List<ApplicationInfo> applist = null;
private ApplicationAdapter listadaptor = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_eclair);
packageManager = getPackageManager();
new LoadApplications().execute();
Button bottone1 = (Button)findViewById(R.id.button1);
bottone1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
new LoadApplications().execute();
}
});};
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
ApplicationInfo app = applist.get(position);
/*
try {
Intent intent = packageManager
.getLaunchIntentForPackage(app.packageName);
if (null != intent) {
startActivity(intent);
}
} catch (ActivityNotFoundException e) {
Toast.makeText(Activity_Eclair.this, e.getMessage(),
Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(Activity_Eclair.this, e.getMessage(),
Toast.LENGTH_LONG).show();
}
*/
Uri packageUri = Uri.parse("package:"+app.packageName);
Intent uninstallIntent =
new Intent(Intent.ACTION_DELETE, packageUri);
startActivity(uninstallIntent);
}
private List<ApplicationInfo> checkForLaunchIntent(List<ApplicationInfo> list) {
ArrayList<ApplicationInfo> applist = new ArrayList<ApplicationInfo>();
for (ApplicationInfo info : list) {
try {
if (null != packageManager.getLaunchIntentForPackage(info.packageName)) {
applist.add(info);
}
} catch (Exception e) {
e.printStackTrace();
}
}
return applist;
}
private class LoadApplications extends AsyncTask<Void, Void, Void> {
public ProgressDialog progress = null;
#Override
protected Void doInBackground(Void... params) {
applist = checkForLaunchIntent(packageManager.getInstalledApplications(PackageManager.GET_META_DATA));
listadaptor = new ApplicationAdapter(Activity_Eclair.this,
R.layout.snippet_list_row, applist);
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
}
protected void onDestroy() {
if(progress!=null)
if(progress.isShowing()){
progress.dismiss();
}
}
#Override
protected void onPostExecute(Void result) {
setListAdapter(listadaptor);
progress.dismiss();
super.onPostExecute(result);
}
#Override
protected void onPreExecute() {
progress = ProgressDialog.show(Activity_Eclair.this, null,
"Caricamento applicazioni in corso...");
super.onPreExecute();
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
}
When I run my application the scroll is very slow, how can I do to make it go smoother without jamming? Any kind of help is welcome. Thanks in advance.

Well, one quick fix I can help you with right now is using a static holder in your getView() method in your adapter. Do the following so that it recycles more efficiently instead of creating new views every time.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
Holder holder;
if (null == view) {
LayoutInflater layoutInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = layoutInflater.inflate(R.layout.snippet_list_row, null);
holder = new Holder();
holder.appName = (TextView) view.findViewById(R.id.app_name);
holder.packageName = (TextView) view.findViewById(R.id.app_paackage);
holder.iconview = (ImageView) view.findViewById(R.id.app_icon);
view.setTag(holder);
}
else
{
holder = (Holder)view.getTag();
}
ApplicationInfo data = appsList.get(position);
if (null != data) {
holder.appName.setText(data.loadLabel(packageManager));
holder.packageName.setText(data.packageName);
holder.iconview.setImageDrawable(data.loadIcon(packageManager));
}
return view;
}
static class Holder
{
TextView appName, packageName;
ImageView iconview;
}
I don't know exactly how much faster this will make your app, but it could help and this is also a common practice way to implement Adapters, so it'd be a good habit to start doing.
Hope this helps. Good luck!

the sloweness you are seeing is probably due to the application image fetch.
you should look at this Lazy load of images in ListView
using a ViewHolder could also help too
http://www.itworld.com/development/380008/how-make-smooth-scrolling-listviews-android

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Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Very slow scroll, context menu and crash by ProgressDialog - java

When you switch orientations, Android will create a new View. You're probably getting crashes because your background thread is trying to change the state on the old one. (It may also be having trouble because your background thread isn't on the UI thread) Post error from logcat

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