Android RecyclerView不显示项目
我有问题为什么RecyclerView不显示项目我不知道为什么不显示项目 json urlAndroid RecyclerView不显示项目,android,android-recyclerview,retrofit,Android,Android Recyclerview,Retrofit,我有问题为什么RecyclerView不显示项目我不知道为什么不显示项目 json url [ { "id": 1, "title": "English", "photo": "en.png", "shortcut": "en" }, { "id": 2, "title": "Spanish", "photo": "es.png", "shortcut": "es" }, { "id": 3, "
[
{
"id": 1,
"title": "English",
"photo": "en.png",
"shortcut": "en"
},
{
"id": 2,
"title": "Spanish",
"photo": "es.png",
"shortcut": "es"
},
{
"id": 3,
"title": "Arabic",
"photo": "ar.png",
"shortcut": "ar"
},
{
"id": 4,
"title": "Russian",
"photo": "ru.png",
"shortcut": "ru"
},
{
"id": 5,
"title": "Portuguese",
"photo": "pt.png",
"shortcut": "pt"
},
{
"id": 6,
"title": "French",
"photo": "fr.png",
"shortcut": "fr"
},
{
"id": 7,
"title": "Turkish",
"photo": "tr.png",
"shortcut": "tr"
}
]
活动
public class CategoriesActivity extends AppCompatActivity {
//mapping
@BindView(R.id.rv_categories)
RecyclerView rv_categories;
CategoriesAdapter categoriesAdapter;
List<CategoriesModel> categoriesModels = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_categories);
ButterKnife.bind(CategoriesActivity.this);
//set data
setData();
}
private void setData() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("***Stackoverflow")
.addConverterFactory(GsonConverterFactory.create())
.build();
RetrofitService retrofitService = retrofit.create(RetrofitService.class);
Call<List<CategoriesModel>> call = retrofitService.get_categories();
call.enqueue(new Callback<List<CategoriesModel>>() {
@Override
public void onResponse(Call<List<CategoriesModel>> call, Response<List<CategoriesModel>> response) {
List<CategoriesModel> list = response.body();
for (CategoriesModel data : list) {
categoriesModels.add(new CategoriesModel(data.id, data.title, data.photo, data.shortcut));
}
rv_categories.setLayoutManager(new GridLayoutManager(CategoriesActivity.this, 2));
categoriesAdapter = new CategoriesAdapter(CategoriesActivity.this, categoriesModels);
rv_categories.setAdapter(categoriesAdapter);
}
@Override
public void onFailure(Call<List<CategoriesModel>> call, Throwable t) {
}
});
}
}
接口
public interface RetrofitService {
//Categories
@GET("Categories/get_categories.php")
Call<List<CategoriesModel>> get_categories();
}
公共接口服务{
//类别
@GET(“Categories/GET_Categories.php”)
调用get_categories();
}
适配器
public class CategoriesAdapter extends RecyclerView.Adapter<CategoriesAdapter.ViewHolder> {
Context context;
List<CategoriesModel> categoriesModels;
public CategoriesAdapter(Context context, List<CategoriesModel> categoriesModels) {
this.context = context;
this.categoriesModels = categoriesModels;
}
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.row_categories, viewGroup, false);
ViewHolder adapterHolder = new ViewHolder(view);
return adapterHolder;
}
@Override
public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {
CategoriesModel categoriesModel = categoriesModels.get(i);
//set photo
Picasso.get().load(viewHolder.url + categoriesModel.photo).into(viewHolder.img_background);
}
@Override
public int getItemCount() {
return categoriesModels.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
//mapping
@BindView(R.id.img_background)
ImageView img_background;
@BindString(R.string.categories)
String url;
public ViewHolder(View view) {
super(view);
ButterKnife.bind(context, view);
}
}
}
公共类CategoriesAdapter扩展了RecyclerView.Adapter{
语境;
列出分类模型;
公共类别适配器(上下文、列表类别模型){
this.context=上下文;
this.categoriesModels=categoriesModels;
}
@凌驾
public ViewHolder onCreateViewHolder(@NonNull ViewGroup ViewGroup,int i){
View View=LayoutInflater.from(viewGroup.getContext()).flate(R.layout.row_类别,viewGroup,false);
ViewHolder adapterHolder=新的ViewHolder(视图);
返回适配器文件夹;
}
@凌驾
public void onBindViewHolder(@NonNull ViewHolder ViewHolder,int i){
CategoriesModel CategoriesModel=categoriesModels.get(i);
//定影
Picasso.get().load(viewHolder.url+categoriesModel.photo).into(viewHolder.img_background);
}
@凌驾
public int getItemCount(){
返回categoriesModels.size();
}
公共类ViewHolder扩展了RecyclerView.ViewHolder{
//映射
@BindView(R.id.img_背景)
图像视图img_背景;
@BindString(R.string.categories)
字符串url;
公共视图持有者(视图){
超级(视图);
绑定(上下文、视图);
}
}
}
行类别
<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/img_background"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5dp">
</ImageView>
activity_categories.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".CategoriesActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_categories"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
从昨天开始,我试图找出问题所在,但没有找到问题,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,我希望能帮助我,非常感谢你,你可以避免这段代码
for (CategoriesModel data : list) {
categoriesModels.add(new CategoriesModel(data.id, data.title, data.photo, data.shortcut));
}
并执行类似于categoriesModels.addAll(list)的操作代码>
在您的ViewHolder中
不需要此选项
@BindString(R.string.categories)
String url;
因为您的R.layout.row\u类别
只包含一个ImageView
尝试将您的行\u categories.xml
更改为以下内容:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="50dp"
android:layout_height="50dp">
<ImageView
android:id="@+id/img_background"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5dp">
</ImageView>
</LinearLayout>
如果不起作用,请尝试将您的onCreate()
更改为以下内容:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_categories);
ButterKnife.bind(CategoriesActivity.this);
rv_categories.setHasFixedSize(true);
rv_categories.setLayoutManager(new GridLayoutManager(CategoriesActivity.this, 2));
setData();
}
编辑
我认为问题就在这里
public class CategoriesModel {
@SerializedName("id")
public String id;
@SerializedName("title")
public String title;
@SerializedName("photo")
public String photo;
@SerializedName("shortcut")
public String shortcut;
public CategoriesModel(String id, String title, String photo, String shortcut) {
this.id = id;
this.title = title;
this.photo = photo;
this.shortcut = shortcut;
}
}
问题就在这里
Picasso.get().load(viewHolder.url + categoriesModel.photo).into(viewHolder.img_background);
你必须把它改成
Picasso.get().load(URL_BASE+"Forvo/Categories/Images/" + categoriesModel.getPhoto()).into(viewHolder.img_background);
您必须为所有这些属性添加Setter
和Getter
我建议您在解析POJO类时使用。请确保预定义图像视图大小。因为加载的图像大小与它相当,除非您声明其他内容
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="50dp"
android:layout_height="50dp">
<ImageView
android:id="@+id/img_background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp">
</ImageView>
然后从谷歌或其他网站上选择一个图像url,该url只在您点击链接时显示图像,以确定您的url参数是否错误。您好,欢迎来到StackOverflow!您从服务器得到什么响应?是否确定已成功获取数据?List=response.body();我想问题就在这里。伙计们,我可以通过Toast打印数据,但不显示在列表中:(RecyclerView在屏幕上有空间吗?添加背景色并在屏幕上查看。)layout@MarcosVasconcelos我有ImageView我编辑了我的帖子我尝试在onBindViewHolder中打印Toast,但没有任何消息您是否尝试打印例如categoriesModel.getSomething()?你想让我给你url JSON以便在你的计算机中进行检查吗?不,按照我的步骤进行操作,它会工作的,按照编辑的步骤进行操作如果它不工作,我会尝试自己进行操作。它正在工作。非常感谢你:D,谢谢你的时间。最好的答案
Picasso.get().load(URL_BASE+"Forvo/Categories/Images/" + categoriesModel.getPhoto()).into(viewHolder.img_background);
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="50dp"
android:layout_height="50dp">
<ImageView
android:id="@+id/img_background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="5dp">
</ImageView>