Java 循环查看特定位置的设置适配器
我使用Java 循环查看特定位置的设置适配器,java,android,android-recyclerview,android-asynctask,jsonhttpclient,Java,Android,Android Recyclerview,Android Asynctask,Jsonhttpclient,我使用Recycleview创建了一个“水平列表视图” 由于我的程序中有async任务,我无法从fetchbook类中检索图书结果,因此我需要在类中设置适配器 我的代码如下所示: @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate( savedInstanceState ); setContentView( R.layout.activity_main ); Arr
Recycleview
创建了一个“水平列表视图”
由于我的程序中有async
任务,我无法从fetchbook类中检索图书结果,因此我需要在类中设置适配器
我的代码如下所示:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
ArrayList<String> names = new ArrayList<>();
names.add("szF_pLGmJTQC");
names.add("QTKD3-mMZFYC");
for (int i = 0; i<names.size(); i++){
fetchBooks(names.get( i ));
}
}
private void fetchBooks(String query) {
client = new MyBookClient();
final ArrayList<String> authors = new ArrayList<>( );
final ArrayList<String> titles = new ArrayList<>( );
final ArrayList<String> image = new ArrayList<>( );
MyBook books = new MyBook();
client.getBooks( query, new JsonHttpResponseHandler(){
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response){
if(response!=null){
MyBook books = MyBook.fromJson(response);
authors.add(books.getAuthor());
titles.add(books.getTitle());
image.add(books.getCoverUrl());
RecyclerView recyclerView = findViewById(R.id.rvAnimals);
LinearLayoutManager horizontalLayoutManager
= new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(horizontalLayoutManager);
adapter = new MyRecyclerViewAdapter(MainActivity.this, authors, titles,image);
adapter.setClickListener(MainActivity.this);
recyclerView.setAdapter(adapter);
Toast.makeText(MainActivity.this, "You clicked " + books.getAuthor(), Toast.LENGTH_SHORT).show();
}
}
});
}
其中,第二个参数i
是适配器内部的位置,因此我可以在位置i=0处获得第一个结果,然后在i=1处获得第二个结果
或者有没有一种方法可以让我从fetchBooks
类返回书籍
多谢各位
但是,它会导致适配器清理上一个视图并在其上添加当前视图
据我所知,您正试图将查询结果添加到RecyclerView列表中,但问题是,在添加新的查询结果时,它会从列表中删除旧的/以前的查询结果。你需要保留所有的结果。如果那是错的,请纠正我
这种行为可能是由于每次在onsuces()
方法中获得新的查询结果时,都会实例化新的适配器。因此,您可以通过将这部分代码转换为onCreate()
方法来避免这种情况;然后,对于每个onSuccess()调用,您只需调用adapter.notifyDataSetChanged()
即可通知适配器其数据源已更改,因此请自行更新
这还要求我们不要用新数据实例化适配器,而只需向适配器添加新方法,以使用.addAll()
方法更新列表
因此,改变:
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
ArrayList<String> names = new ArrayList<>();
names.add("szF_pLGmJTQC");
names.add("QTKD3-mMZFYC");
RecyclerView recyclerView = findViewById(R.id.rvAnimals);
LinearLayoutManager horizontalLayoutManager
= new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(horizontalLayoutManager);
adapter = new MyRecyclerViewAdapter(MainActivity.this, new ArrayList<>(), new ArrayList<>(), new ArrayList<>());
adapter.setClickListener(MainActivity.this);
recyclerView.setAdapter(adapter);
for (int i = 0; i<names.size(); i++){
fetchBooks(names.get( i ));
}
}
private void fetchBooks(String query) {
client = new MyBookClient();
MyBook books = new MyBook();
client.getBooks( query, new JsonHttpResponseHandler(){
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response){
if(response!=null){
MyBook books = MyBook.fromJson(response);
adapter.addBooks(books.getAuthor(), books.getTitle(), books.getCoverUrl());
Toast.makeText(MainActivity.this, "You clicked " + books.getAuthor(), Toast.LENGTH_SHORT).show();
}
}
});
}
如果您需要进一步的帮助,我非常欢迎如果可能,请发布您的适配器代码。非常感谢您的回答。你完全理解我。一件事是类型不兼容,因为books.getAuthor是一个字符串,而在addbooks中它需要列表。还加了我的书。@Ben对不起,是我的错。。您可以用add()替换适配器中的addAll(),请告诉我结果;我更新了答案,不过为了进一步澄清,对不起,伙计,没有错误,但是适配器不会显示任何结果。它是空的。:(让我检查一下,againI已经在一个简单的示例中测试过了,它可以工作;我不确定这里出了什么问题;但是作为一个建议,为什么不将标题、作者和图像添加到一个模型/POJO类中,您只需在适配器中添加一个列表就可以了?
public class MyBook implements Serializable {
private String author;
private String title;
private String bookid;
private String rating;
public String getTitle() {
return title;
}
public String getAuthor() {
return author;
}
public String getId() {
return bookid;
}
public String getRating(){
return rating;
}
public static MyBook fromJson(JSONObject jsonObject) {
MyBook book = new MyBook();
try {
JSONObject volumeInfo = jsonObject.getJSONObject( "volumeInfo" );
book.title = volumeInfo.has("title") ? volumeInfo.getString("title") : "";
book.author = getAuthor(volumeInfo);
book.bookid = jsonObject.has("id") ? jsonObject.getString("id") : "";
book.rating = volumeInfo.has("averageRating") ? String.valueOf(volumeInfo.getDouble("averageRating")) : "0";
} catch (JSONException e) {
e.printStackTrace();
return null;
}
return book;
}
private static String getAuthor(final JSONObject jsonObject) {
try {
final JSONArray authors = jsonObject.getJSONArray("authors");
int numAuthors = authors.length();
final String[] authorStrings = new String[numAuthors];
for (int i = 0; i < numAuthors; ++i) {
authorStrings[i] = authors.getString(i);
}
return TextUtils.join(", ", authorStrings);
} catch (JSONException e) {
return "";
}
}
}
fetchBooks(names.get( i ), i);
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
ArrayList<String> names = new ArrayList<>();
names.add("szF_pLGmJTQC");
names.add("QTKD3-mMZFYC");
RecyclerView recyclerView = findViewById(R.id.rvAnimals);
LinearLayoutManager horizontalLayoutManager
= new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(horizontalLayoutManager);
adapter = new MyRecyclerViewAdapter(MainActivity.this, new ArrayList<>(), new ArrayList<>(), new ArrayList<>());
adapter.setClickListener(MainActivity.this);
recyclerView.setAdapter(adapter);
for (int i = 0; i<names.size(); i++){
fetchBooks(names.get( i ));
}
}
private void fetchBooks(String query) {
client = new MyBookClient();
MyBook books = new MyBook();
client.getBooks( query, new JsonHttpResponseHandler(){
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response){
if(response!=null){
MyBook books = MyBook.fromJson(response);
adapter.addBooks(books.getAuthor(), books.getTitle(), books.getCoverUrl());
Toast.makeText(MainActivity.this, "You clicked " + books.getAuthor(), Toast.LENGTH_SHORT).show();
}
}
});
}
public void addBook(String author, String title, String image) {
this.mViewAuthor.add(author);
this.mTitles.add(title);
this.mimages.add(image);
this.notifyDataSetChanged();
}