Question

int i = 0; //used for getting item position
for (Iterator<CustomObject> iterator = mAdapter.getItemsData().iterator(); iterator.hasNext();) {

    if (mAdapter.getItemsData().get(i).getPriceTier() != 1) { //if statement throws error
        // Remove the current element from the iterator and the list.
        iterator.remove();
        mAdapter.removeFromItemsData(i);
    }
    i++;
}

使用this stackoverflow答案，我遍历我的CustomObject的arraylist。自定义对象只是一个带有setter和getter的POJO类。 setter和getter有不同的数据类型，例如int，String，double等。

mAdapter.getItemsData从适配器类返回araylist。

//method just notifies the RecyclerView that an item was removed.
public void removeFromItemsData(int position){

    notifyItemRemoved(position);
}

这是例外

java.lang.IndexOutOfBoundsException：索引18无效，大小为18 at java.util.ArrayList.throwIndexOutOfBoundsException（ArrayList.java:255）在java.util.ArrayList.get（ArrayList.java:308）at com.test.TestActivity $ 5.onClick（TestActivity.java:280）at android.view.View.performClick（View.java:4780）at android.view.View $ PerformClick.run（View.java:19866）at android.os.Handler.handleCallback（Handler.java:739）at android.os.Handler.dispatchMessage（Handler.java:95）at android.os.Looper.loop（Looper.java:135）at android.app.ActivityThread.main（ActivityThread.java:5254）at java.lang.reflect.Method.invoke（Native Method）at java.lang.reflect.Method.invoke（Method.java:372）at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:903）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:698）

CustomObject类

public class CustomObject{
    private String name;
    private int distance;
    private String category;
    private String id;
    private double rating;
    private String ratingColor;
    private String prefix;
    private String suffix;
    private int priceTier;
    private String currency;
    private String phone;
    private String twitter;
    private String url;
    private String menu;
    String address;
    String city;
    String state;
    String postalCode;
    double lat;
    double lng;
    String review;
    int reviewCount;
    String firstName;
    String lastName;
    String userIconPrefix;
    String userIconSuffix;
    String secondsReview;

    public CustomObject() {
        this.name = "";
        this.distance = 0;
        this.setCategory("");
        this.id = "";
        this.rating = 0;
        this.ratingColor = "";
        this.prefix = "";
        this.suffix = "";
        this.priceTier = 0;
        this.currency = "";
        this.phone = "";
        this.twitter = "";
        this.url = "";
        this.menu = "";
        this.address = "";
        this.city = "";
        this.state = "";
        this.postalCode = "";
        this.lat = 0;
        this.lng = 0;
        this.review = "";
        this.reviewCount = 0;
        this.firstName = "";
        this.lastName = "";
        this.userIconPrefix = "";
        this.userIconSuffix = "";
        this.secondsReview = "";
    }

    public void setSecondsReview(String secondsReview){
        this.secondsReview = secondsReview;
    }

    public String getSecondsReview(){
        return secondsReview;
    }

    public void setUserIconSuffix(String userIconSuffix){
        this.userIconSuffix = userIconSuffix;
    }

    public String getUserIconSuffix(){
        return userIconSuffix;
    }

    public void setUserIconPrefix(String userIconPrefix){
        this.userIconPrefix = userIconPrefix;
    }

    public String getUserIconPrefix(){
        return userIconPrefix;
    }

    public void setFirstName(String firstName){
        this.firstName = firstName;
    }

    public String getFirstName(){
        return firstName;
        //todo if String firstNAme == null, then return "a foursquare user"
    }

    public void setLastName(String lastName){
        this.lastName = lastName;
    }

    public String getLastName(){
        return lastName;
    }

    public void setReviewCount(int reviewCount){
        this.reviewCount = reviewCount;
    }

    public int getReviewCount(){
        return reviewCount;
    }

    public void setReview(String review){
        this.review = review;
    }

    public String getReview(){
        return review;
    }

    public void setLng(double lng){
        this.lng = lng;
    }

    public double getLng(){
        return lng;
    }

    public void setLat(double lat){
        this.lat = lat;
    }

    public double getLat(){
        return lat;
    }

    public void setPostalCode(String postalCode){
        this.postalCode = postalCode;
    }

    public String getPostalCode(){
        return postalCode;
    }

    public void setState(String state){
        this.state = state;
    }

    public String getState(){
        return state;
    }

    public void setCity(String city){
        this.city = city;
    }

    public String getCity(){
        return city;
    }

    public void setAddress(String address){
        this.address = address;
    }

    public String getAddress(){
        return address;
    }

    public void setMenuUrl(String menu){
        this.menu = menu;
    }

    public String getMenuUrl(){
        return menu;
    }

    public void setUrl(String url){
        this.url = url;
    }

    public String getUrl(){
        return url;
    }

    public void setTwitter(String twitter){
        this.twitter = twitter;
    }

    public String getTwitter(){
        return twitter;
    }

    public void setPhone(String phone){
        this.phone = phone;
    }

    public String getPhone(){
        return phone;
    }

    public String getCurrency(){
        return currency;
    }

    public void setCurrency(String currency){
        this.currency = currency;
    }

    public int getPriceTier(){
        return priceTier;
    }

    public void setPriceTier(int priceTier){
        this.priceTier = priceTier;
    }

    public String getSuffix(){
        return suffix;
    }

    public void setSuffix(String suffix){
        this.suffix = suffix;
    }

    public  String getPrefix(){
        return prefix;
    }

    public void setPrefix(String prefix){
        this.prefix = prefix;
    }

    public double getRating(){
        if(rating > 0){
            return rating;
        }
        return 0; //TODO display symbol if rating not found
    }

    public void setRating(double rating){
        this.rating = rating;
    }

    public Integer getDistance() {
        if (distance >= 0) {
            return distance;
        }
        return 0; //TODO display symbol if distance not found, like N/A
    }

    public void setDistance(int distance) {
            this.distance = distance;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }

}

如何添加数据

在onCreate of activity中，我实例化Recyclerview。 RecyclerView需要一个arraylist，所以我通过一个空的。

List listTitle = new ArrayList(); //empty arraylist
mAdapter = new Fragment1Adapter(listTitle);

RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mRecyclerView.setAdapter(mAdapter);

稍后在AsyncTask中，我将项目添加到适配器。

for (int i = 0; i < jsonArray.length(); i++) { 
    CustomObject poi = new CustomObject ();

    if (jsonArray.getJSONObject(i).has("venue")) {
        poi.setName(jsonArray.getJSONObject(i).getJSONObject("venue").getString("name"));
        poi.setId(jsonArray.getJSONObject(i).getJSONObject("venue").getString("id"));
    }
    mAdapter.addItem(poi);
}

这是addItem类

在适配器类private final List<FoursquareVenue> itemsData;

的顶部声明

public void addItem(FoursquareVenue data) {
        itemsData.add(data);
        notifyItemInserted(itemsData.size() - 1);
    }

Answer 1

修改

由于您的聊天和编辑：

您需要向ArrayList添加和删除项目，并通知适配器更改。

CustomObject poi = new CustomObject (); if (jsonArray.getJSONObject(i).has("venue")) { poi.setName(jsonArray.getJSONObject(i).getJSONObject("venue").getString("name")); poi.setId(jsonArray.getJSONObject(i).getJSONObject("venue").getString("id")); } listTitle.addItem(poi);// Add to ListArray

然后遍历您的ArrayList以删除项目。

您只是在尝试访问数据时遇到了一些麻烦。

存在一个问题，即您正在创建CustomObjects的迭代器，并将其解析为mAdapter.getItemsData()的数据类型。

从迭代器中删除元素应该从列表中删除它。

for (Iterator<CustomObject> iterator = mAdapter.iterator(); iterator.hasNext();) { CustomObject itemsData = iterator.next(); if (itemsData.getItemsData().get(i).getPriceTier() != 1) { //if statement throws error // Remove the current element from the iterator and the list. iterator.remove(); } i++; } CustomObject itemsData = iterator.next();

如果有帮助，请告诉我。

java.lang.IndexOutOfBoundsException：索引18无效，大小为18

1 个答案: