Это тип listView, который я пытаюсь создать: когда пользователь нажимает на список, он переводит пользователя в newActivity, где пользователь находит полное содержимое listView. И на longPressed добавляет элемент списка в FavoritesList.
После изучения учебника о том, как добавить FavoritesActivity в ListView с BaseAdapter, я получил ошибку. Это;мое приложение принудительно закрывается при запуске. Я знаю, что пропустил некоторые строки или, возможно, неосознанно добавил неформатированные объекты, которые могут привести к сбою приложения. Я включил отчет logCat для вас, чтобы помочь мне решить проблему, которая вызывает сбой. Я новичок в программировании, и я хочу учиться с помощью этой программы. Я студент, пожалуйста, мне нужна ваша помощь, чтобы завершить мой проект.
Все мои ошибки и ошибки включены в показанные коды. Пожалуйста, я хочу, чтобы вы помогли мне с решением проблемы. Спасибо
Это MainActivity.java
public class MainActivity extends AppCompatActivity implements SearchView.OnQueryTextListener {
private String TAG = "MainActivity ----- ; " ;
// Store instance variables
private int page;
private ConsentForm form;
ListView listView;
ListViewAdapter adapter;
String[] title;
String[] description;
int[] icon;
ArrayList<Model> arrayList = new ArrayList<Model>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getSupportActionBar();
actionBar.setTitle("Redeemed Songs");
title = new String[]{"This is the lyrics content example of the song1, This is the lyrics content example of the song2, This is the lyrics content example of the song3, This is the lyrics content example of the song4, This is the lyrics content example of the song5",};
description = new String[]{"MORNING", "MORNING", "MORNING", "MORNING", "MORNING", "MORNING",};
icon = new int[]{ R.drawable.song, R.drawable.song, R.drawable.song, R.drawable.song,R.drawable.song,R.drawable.song,};
listView = findViewById(R.id.list);
for (int i =0; i<title.length; i++){
Model model =new Model(title[i], description[i], icon[i]);
//bind all strings in an array
arrayList.add(model);
}
//pass result to listview class
adapter = new ListViewAdapter(this, arrayList);
//bind the adapter to the listview class
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
MenuItem myActionMenuItem = menu.findItem(R.id.action_search);
SearchView searchView = (SearchView)myActionMenuItem.getActionView();
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String s) {
return false;
}
@Override
public boolean onQueryTextChange(String s) {
if (TextUtils.isEmpty(s)){
adapter.filter("");
listView.clearTextFilter();
}
else {
adapter.filter(s);
}
return true;
}
});
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id==R.id.action_settings){
Toast.makeText(this, "Settings", Toast.LENGTH_SHORT).show();
startActivity(new Intent(this, Main2Activity.class));
return true;
//do your funtionality here
}
else if (id==R.id.action_howtouse){
Toast.makeText(this, "manual", Toast.LENGTH_SHORT).show();
startActivity(new Intent(this, Main3Activity.class));
return true;
//do your funtionality here
}
else if (id==R.id.action_developers){
Toast.makeText(this, "Favorites", Toast.LENGTH_SHORT).show();
startActivity(new Intent(this, Main4Activity.class));
return true;
//do your funtionality here
}
return super.onOptionsItemSelected(item);
}
@Override
public boolean onQueryTextSubmit(String query) {
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
return false;
}
}
Это Model.java Класс
public class Model {
String title;
String desc;
int icon;
int fav_icon;
public Model(int fav_icon) {
this.fav_icon = fav_icon;
}
public int getFav_icon() {
return fav_icon;
}
//constructor
public Model(String title, String desc, int icon) {
this.title = title;
this.desc = desc;
this.icon = icon;
}
//getters
public String getTitle() {
return title;
}
public String getDesc() {
return desc;
}
public int getIcon() {
return icon;
}
}
Это row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:padding="10dp">
<ImageView
android:id="@+id/mainIcon"
android:src="@drawable/song"
android:layout_width="30dp"
android:layout_height="40dp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center"
android:layout_marginLeft="5dp"
android:layout_marginStart="5dp">
<TextView
android:id="@+id/mainTitle"
android:textStyle="bold"
android:textColor="#740303"
android:text="Title"
android:textSize="15sp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/mainDesc"
android:text="Description"
android:textColor="#262626"
android:textSize="12sp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="@+id/list_fav_icon"
android:layout_width="0dp"
android:layout_height="match_parent"
android:src="@drawable/ic_favorite_active"
android:layout_gravity="right"
android:layout_margin="5dp"
android:layout_weight="1"/>
</LinearLayout>
</LinearLayout>
Это класс ListViewAdapter.java
public class ListViewAdapter extends BaseAdapter{
//Variables
Context mContext;
LayoutInflater inflater;
List<Model> modellist;
ArrayList<Model> arrayList;
private Model model;
CheckBox checkFavoriteItem;
SharedPreference sharedPreference;
//Constructor
public ListViewAdapter(Context context, List<Model> modellist) {
mContext = context;
this.modellist = modellist;
inflater = LayoutInflater.from(mContext);
this.arrayList = new ArrayList<Model>();
this.arrayList.addAll(modellist);
}
public class ViewHolder{
TextView mTitleTv, mDescTv;
ImageView mIconTv, favIcon;
}
@Override
public int getCount() {
return modellist.size();
}
@Override
public Object getItem(int i) {
return modellist.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(final int i, View view, ViewGroup parent) {
final ViewHolder holder;
if (view==null){
holder = new ViewHolder();
view = inflater.inflate(R.layout.row, null);
//locate the views in row.xml
holder.mTitleTv = (TextView) view.findViewById(R.id.mainTitle);
holder.mDescTv = (TextView) view.findViewById(R.id.mainDesc);
holder.mIconTv = view.findViewById(R.id.mainIcon);
holder.favIcon = view.findViewById(R.id.list_fav_icon);
view.setTag(holder);
}
else {
holder = (ViewHolder)view.getTag();
}
//set the result into textview
Model model = (Model) getItem(i);
holder.mTitleTv.setText(modellist.get(i).getTitle());
holder.mDescTv.setText(modellist.get(i).getDesc());
//Set the result in imagview
holder.mIconTv.setImageResource(modellist.get(i).getIcon());
holder.favIcon.setImageResource(modellist.get(i).getFav_icon());
if (checkFavoriteItem(model)) {
holder.favIcon.setImageResource(R.drawable.ic_favorite_active);
holder.favIcon.setTag("yes");
} else {
holder.favIcon.setImageResource(R.drawable.ic_favorite_default);
holder.favIcon.setTag("no");
}
//listview item clicks
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//code later
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song1")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 001");
intent.putExtra("contentTv", "This is the lyrics content example of the song2");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song1")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 002");
intent.putExtra("contentTv", "This is the lyrics content example of the song2");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song3")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 003");
intent.putExtra("contentTv", "This is the lyrics content example of the song3");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song4")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 004");
intent.putExtra("contentTv", "This is the lyrics content example of the song4");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song5")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 005");
intent.putExtra("contentTv", "This is the lyrics content example of the song5");
mContext.startActivity(intent);
}
}
});
final ImageView favoritesbutton = (ImageView) view.findViewById(R.id.list_fav_icon);
favoritesbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String tag = favoritesbutton.getTag().toString();
if (tag.equalsIgnoreCase("no")){
sharedPreference.addFavorite(mContext, modellist.get(i));
Toast.makeText(mContext, R.string.add_favr, Toast.LENGTH_SHORT).show();
favoritesbutton.setTag("yes");
favoritesbutton.setImageResource(R.drawable.ic_favorite_active);
}else{
sharedPreference.removeFavorite(mContext, modellist.get(i));
favoritesbutton.setTag("no");
favoritesbutton.setImageResource(R.drawable.ic_favorite_default);
Toast.makeText(mContext, R.string.favorites_remove_msg, Toast.LENGTH_SHORT).show();
}
}
});
return view;
}
//Checks whether a particular product exists in SharedPreferences*/
public boolean checkFavoriteItem(Model checkCode) {
boolean check = false;
List<Model> favorites = sharedPreference.getFavorites(mContext);
if (favorites != null) {
for (Model model : favorites) {
if (model.equals(checkCode)) {
check = true;
break;
}
}
}
return check;
}
public void add(Model model) {
modellist.add(model);
notifyDataSetChanged();
}
public void remove(Model model) {
modellist.remove(model);
notifyDataSetChanged();
}
//filter
public void filter(String charText){
charText = charText.toLowerCase(Locale.getDefault());
modellist.clear();
if (charText.length()==0){
modellist.addAll(arrayList);
}
else {
for (Model model : arrayList){
if (model.getTitle().toLowerCase(Locale.getDefault()).contains(charText)){
modellist.add(model);
}
}
}
notifyDataSetChanged();
}
}
Это класс SharedPreference.java для сохраненного значения
public class SharedPreference {
public static final String PREFS_NAME = "REDEEMED_APP";
public static final String FAVORITES = "code_Favorite";
public SharedPreference() {
super();
}
// This four methods are used for maintaining favorites.
public void saveFavorites(Context context, List<Model> favorites) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
editor = settings.edit();
Gson gson = new Gson();
String jsonFavorites = gson.toJson(favorites);
editor.putString(FAVORITES, jsonFavorites);
editor.commit();
}
public void addFavorite(Context context, Model product) {
List<Model> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<Model>();
favorites.add(product);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, Model model) {
ArrayList<Model> favorites = getFavorites(context);
if (favorites != null) {
favorites.remove(model);
saveFavorites(context, favorites);
}
}
public ArrayList<Model> getFavorites(Context context) {
SharedPreferences settings;
List<Model> favorites;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
Model[] favoriteItems = gson.fromJson(jsonFavorites,
Model[].class);
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<Model>(favorites);
} else
return null;
return (ArrayList<Model>) favorites;
}
}
Thisкласс MyFavoriteActivity.java, предназначенный для отображения сохраненного списка
public class MyFavoriteActivity extends AppCompatActivity {
SharedPreference sharedPreference;
List<Model> favorites;
FavouritesAdapter favouritesAdapter;
Context context = this.context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_favorite);
sharedPreference = new SharedPreference();
favorites = sharedPreference.getFavorites(MyFavoriteActivity.this);
if (favorites == null){
Dialog dialog = new Dialog(MyFavoriteActivity.this);
dialog.setTitle(R.string.no_favorites_items);
dialog.show();
}else {
if (favorites.size() ==0){
Dialog dialog = new Dialog(MyFavoriteActivity.this);
dialog.setTitle(R.string.no_favorites_items);
dialog.show();
}
ListView favList = (ListView) findViewById(R.id.FavoriteLayoutListView);
if(favorites != null){
favouritesAdapter = new FavouritesAdapter(MyFavoriteActivity.this, favorites);
favList.setAdapter(favouritesAdapter);
favList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View arg1,
int position, long arg3) {
}
});
favList.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
ImageView button = (ImageView) view
.findViewById(R.id.list_fav_icon);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("no")) {
sharedPreference.addFavorite(MyFavoriteActivity.this,
favorites.get(position));
Toast.makeText(
MyFavoriteActivity.this,
R.string.add_favr,
Toast.LENGTH_SHORT).show();
button.setTag("yes");
button.setImageResource(R.drawable.ic_favorite_active);
} else {
sharedPreference.removeFavorite(MyFavoriteActivity.this,
favorites.get(position));
button.setTag("no");
button.setImageResource(R.drawable.ic_favorite_default);
Toast.makeText(
MyFavoriteActivity.this,
R.string.remove_favr,
Toast.LENGTH_SHORT).show();
}
return true;
}
});
}
}
}
}
Это FavoriteListAdapter.java.class
public class FavouritesAdapter extends BaseAdapter{
//Variables
Context mContext;
LayoutInflater inflater;
List<Model> modellist;
ArrayList<Model> arrayList;
private Model model;
//Constructor
public FavouritesAdapter(Context context, List<Model> modellist) {
mContext = context;
this.modellist = modellist;
inflater = LayoutInflater.from(mContext);
this.arrayList = new ArrayList<Model>();
this.arrayList.addAll(modellist);
}
public class ViewHolder{
TextView mTitleTv, mDescTv;
ImageView mIconTv, favIcon;
}
@Override
public int getCount() {
return modellist.size();
}
@Override
public Object getItem(int i) {
return modellist.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(final int i, View view, ViewGroup parent) {
final ViewHolder holder;
if (view==null){
holder = new ViewHolder();
view = inflater.inflate(R.layout.row, null);
//locate the views in row.xml
holder.mTitleTv = (TextView) view.findViewById(R.id.mainTitle);
holder.mDescTv = (TextView) view.findViewById(R.id.mainDesc);
holder.mIconTv = view.findViewById(R.id.mainIcon);
view.setTag(holder);
}
else {
holder = (ViewHolder)view.getTag();
}
//set the result into textview
holder.mTitleTv.setText(modellist.get(i).getTitle());
holder.mDescTv.setText(modellist.get(i).getDesc());
//Set the result in imagview
holder.mIconTv.setImageResource(modellist.get(i).getIcon());
//listview item clicks
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//code later
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song1")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 001");
intent.putExtra("contentTv", "This is the lyrics content example of the song2");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song1")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 002");
intent.putExtra("contentTv", "This is the lyrics content example of the song2");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song3")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 003");
intent.putExtra("contentTv", "This is the lyrics content example of the song3");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song4")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 004");
intent.putExtra("contentTv", "This is the lyrics content example of the song4");
mContext.startActivity(intent);
}
if (modellist.get(i).getTitle().equals("This is the lyrics content example of the song5")){
//start NewActivity with title for actionbar and text for textview
Intent intent = new Intent(mContext, NewActivity.class);
intent.putExtra("actionBarTitle", "Song 005");
intent.putExtra("contentTv", "This is the lyrics content example of the song5");
mContext.startActivity(intent);
}
}
});
return view;
}
//filter
public void filter(String charText){
charText = charText.toLowerCase(Locale.getDefault());
modellist.clear();
if (charText.length()==0){
modellist.addAll(arrayList);
}
else {
for (Model model : arrayList){
if (model.getTitle().toLowerCase(Locale.getDefault()).contains(charText)){
modellist.add(model);
}
}
}
notifyDataSetChanged();
}
}
Это LogCat
--------- beginning of crash
2019-10-22 02:02:39.715 11214-11214/com.gritchen.redeemedsongs E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.gritchen.redeemedsongs, PID: 11214
java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.ArrayList com.gritchen.redeemedsongs.SharedPreference.getFavorites(android.content.Context)' on a null object reference
at com.gritchen.redeemedsongs.ListViewAdapter.checkFavoriteItem(ListViewAdapter.java:372)
at com.gritchen.redeemedsongs.ListViewAdapter.getView(ListViewAdapter.java:86)
at android.widget.AbsListView.obtainView(AbsListView.java:2365)
at android.widget.ListView.makeAndAddView(ListView.java:2052)
at android.widget.ListView.fillDown(ListView.java:786)
at android.widget.ListView.fillFromTop(ListView.java:847)
at android.widget.ListView.layoutChildren(ListView.java:1826)
at android.widget.AbsListView.onLayout(AbsListView.java:2164)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1083)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:443)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:764)
at android.view.View.layout(View.java:20323)
at android.view.ViewGroup.layout(ViewGroup.java:6199)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2612)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2317)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1453)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7047)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:924)
at android.view.Choreographer.doCallbacks(Choreographer.java:732)
at android.view.Choreographer.doFrame(Choreographer.java:664)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:910)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6524)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:888)
2019-10-22 02:02:39.737 11214-11253/com.gritchen.redeemedsongs D/NetworkSecurityConfig: No Network Security Config specified, using platform default
2019-10-22 02:02:39.899 11214-11253/com.gritchen.redeemedsongs D/libc-netbsd: getaddrinfo: get result from proxy gai_error = 0
2019-10-22 02:02:39.918 11214-11253/com.gritchen.redeemedsongs I/System.out: port:443
2019-10-22 02:02:41.595 11214-11239/com.gritchen.redeemedsongs