Java 如何在android中使用SharedReference向ListView活动添加收藏夹列表活动
这就是我试图创建的listView类型：当用户单击列表时，它会将用户带到newActivity，用户将在其中找到listView的完整内容。并在长按时将列表项添加到favoritesList 在学习了有关如何使用BaseAdapter在Listview中添加favoritesActivity的教程之后，我遇到了一个错误。就是,；我的应用程序在启动时强制关闭。我知道我遗漏了一些行，或者可能在不知不觉中添加了可能导致应用程序崩溃的非格式化对象。我已经为您提供了logCat报告，以帮助我修复导致崩溃的问题。我是编程新手，我想学习使用这个程序。我是一名学生，我需要你的帮助，以便完成我的项目 我的所有尝试和错误都包含在显示的代码中。请你帮我解决问题。谢谢 这是MainActivity.javaJava 如何在android中使用SharedReference向ListView活动添加收藏夹列表活动,java,android,xml,Java,Android,Xml,这就是我试图创建的listView类型：当用户单击列表时，它会将用户带到newActivity，用户将在其中找到listView的完整内容。并在长按时将列表项添加到favoritesList 在学习了有关如何使用BaseAdapter在Listview中添加favoritesActivity的教程之后，我遇到了一个错误。就是,；我的应用程序在启动时强制关闭。我知道我遗漏了一些行，或者可能在不知不觉中添加了可能导致应用程序崩溃的非格式化对象。我已经为您提供了logCat报告，以帮助我修复导致崩溃的
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;
}
}
<?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>
List<Model> favorites = sharedPreference.getFavorites(mContext);
List favorites=SharedReference.getFavorites（mContext）；
//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);
this.sharedPreference = new SharedPreference();
}
//构造函数
公共ListViewAdapter（上下文上下文，列表模型列表）{
mContext=上下文；
this.modellist=modellist；
充气器=从（mContext）开始的充气器；
this.arrayList=新的arrayList（）；
this.arrayList.addAll（modellist）；
this.SharedReference=新的SharedReference（）；
}
List<Model> favorites = sharedPreference.getFavorites(mContext);
List favorites=SharedReference.getFavorites（mContext）；
//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);
this.sharedPreference = new SharedPreference();
}
//构造函数
公共ListViewAdapter（上下文上下文，列表模型列表）{
mContext=上下文；
this.modellist=modellist；
充气器=从（mContext）开始的充气器；
this.arrayList=新的arrayList（）；
this.arrayList.addAll（modellist）；
this.SharedReference=新的SharedReference（）；
}
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();
}
}
--------- 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
List<Model> favorites = sharedPreference.getFavorites(mContext);
//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);
this.sharedPreference = new SharedPreference();
}