如何在 Android 分页库中为列表、过滤器和搜索维护相同的数据源
How to maintain same DataSource for List,Filter and Search in Android Paging Library
我有 activity 显示项目列表以及过滤器和搜索选项。我正在使用 android 分页库显示项目。第一次加载项目列表时,当我滚动到下一组加载项目的底部时,它的工作正常。但我也想过滤项目并搜索项目。在过滤或搜索项目时,我正在使现有的 source.if 无效,我不会使过滤器和搜索的数据源无效 api 不是 firing.I 想要根据我的过滤器和搜索加载新项目列表使用数据源的密钥。
executor = Executors.newFixedThreadPool(5);
celebrityDataFactory = new CelebrityDataFactory(apicallInterface, mFansismParam);
networkState = Transformations.switchMap(celebrityDataFactory.getCelebrityData(),
dataSource -> dataSource.getNetworkState());
PagedList.Config pagedListConfig =
(new PagedList.Config.Builder())
.setEnablePlaceholders(false)
.setPrefetchDistance(8)
.setInitialLoadSizeHint(10)
.setPageSize(20).build();
if (!mFansismParam.getCategoryId().isEmpty()) {
celebrityDetails = new LivePagedListBuilder(celebrityDataFactory, pagedListConfig)
.setFetchExecutor(executor)
.build();
} else(!mFansismParam.getProfessionId().isEmpty()) {
celebrityDetails = new LivePagedListBuilder(celebrityDataFactory, pagedListConfig)
.setFetchExecutor(executor)
.build();
}
创建数据源的数据工厂
@Override
public DataSource create() {
celebrityDataSource = new CelebrityDataSource(apicallInterface, params);
celebrityData.postValue(celebrityDataSource);
return celebrityDataSource;
}
改造API调用:
Call<CelebrityList> getCelebrityList(@Query("categoryId") String categoryId,
@Query("professionId") String professionId,
@Query("page") String pageNumber,
@Query("name") String searchKey);
数据源Api回调:
apicallInterface.getCelebrityList(requestParams.getCategoryId(), "", "1", "").enqueue(new Callback<CelebrityList>() {
@Override
public void onResponse(Call<CelebrityList> call, Response<CelebrityList> response) {
if (response.isSuccessful()) {
initialLoading.postValue(NetworkState.LOADED);
networkState.postValue(NetworkState.LOADED);
if (!response.body().getData().isEmpty()) {
callback.onResult(response.body().getData(), null, "2");
} else {
networkState.postValue(new NetworkState(NetworkState.Status.SUCCESS, "No more results"));
}
} else {
initialLoading.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
networkState.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
}
}
您需要将搜索关键字保留在实时数据中,以便分页列表可以在更改时更改。所以在你的视图模型中,定义:
public MutableLiveData<String> filterTextAll = new MutableLiveData<>();
由于页面列表也被定义为 LiveData,这可以借助转换来完成。转换 class 为您提供了可以更改 LiveData 对象中的值的函数。 swithMap 函数 returns 一个新的 LiveData 对象而不是一个值,在您的情况下,通过在引擎盖下创建新的数据源,切换搜索键以获取与搜索键对应的 pagedList 对象。
pagedListLiveData = Transformations.switchMap(filterTextAll, input -> {
MyDataSourceFactory myDataSourceFactory = new MyDataSourceFactory(executor,input);
myDataSource = myDataSourceFactory.getMyDataSourceMutableLiveData();
networkState = Transformations.switchMap(myDataSource,
dataSource -> dataSource.getNetworkState());
return (new LivePagedListBuilder(myDataSourceFactory, pagedListConfig))
.setFetchExecutor(executor)
.build();
});
您可以更改 DataSourceFactory 和 DataSource 构造函数以添加 searchKey 参数:
public class MyDataSourceFactory extends DataSource.Factory {
MutableLiveData<MyDataSource> myDataSourceMutableLiveData;
private MyDataSource myDataSource;
private Executor executor;
private String searchKey;
public MyDataSourceFactory(Executor executor , String searchKey) {
this.executor= executor;
this.searchKey= searchKey;
this.myDataSourceMutableLiveData= new MutableLiveData<>();
}
@Override
public DataSource create() {
//*notice: It's important that everytime a DataSource factory create() is invoked a new DataSource instance is created
myDataSource= new MyDataSource(executor, searchKey);
myDataSourceMutableLiveData.postValue(myDataSource);
return myDataSource;
}
public MutableLiveData<MyDataSource> getMyDataSourceMutableLiveData() {
return myDataSourceMutableLiveData;
}
public MyDataSource getMyDataSource() {
return myDataSource;
}
}
对 DataSource 构造函数执行与上面相同的操作,以传递 searchKey 以在 api 调用中使用。
还有一件事仍然存在,在你的 Activity/Fragment (lifeCycleOwner) 中设置 filterTextAll mutableLiveData 的值,每当搜索键更改被触发时,比如触发 searchview onQueryTextChange 或你喜欢的任何事件。
private void performSearch(String searchKey) {
// TODO: Perform the search and update the UI to display the results.
myViewModel.filterTextAll.setValue(searchKey);
myViewModel.pagedListLiveData.observe(owner, new Observer<PagedList<MyItem>>() {
@Override
public void onChanged(PagedList<MyItem> myItems) {
myAdapter.submitList(myItems);
}
});
myViewModel.networkState.observe(owner, new Observer<NetworkState>() {
@Override
public void onChanged(NetworkState networkState) {
myAdapter.setNetworkState(networkState);
}
});
myRecyclerView.setAdapter(myAdapter);
}
我有 activity 显示项目列表以及过滤器和搜索选项。我正在使用 android 分页库显示项目。第一次加载项目列表时,当我滚动到下一组加载项目的底部时,它的工作正常。但我也想过滤项目并搜索项目。在过滤或搜索项目时,我正在使现有的 source.if 无效,我不会使过滤器和搜索的数据源无效 api 不是 firing.I 想要根据我的过滤器和搜索加载新项目列表使用数据源的密钥。
executor = Executors.newFixedThreadPool(5);
celebrityDataFactory = new CelebrityDataFactory(apicallInterface, mFansismParam);
networkState = Transformations.switchMap(celebrityDataFactory.getCelebrityData(),
dataSource -> dataSource.getNetworkState());
PagedList.Config pagedListConfig =
(new PagedList.Config.Builder())
.setEnablePlaceholders(false)
.setPrefetchDistance(8)
.setInitialLoadSizeHint(10)
.setPageSize(20).build();
if (!mFansismParam.getCategoryId().isEmpty()) {
celebrityDetails = new LivePagedListBuilder(celebrityDataFactory, pagedListConfig)
.setFetchExecutor(executor)
.build();
} else(!mFansismParam.getProfessionId().isEmpty()) {
celebrityDetails = new LivePagedListBuilder(celebrityDataFactory, pagedListConfig)
.setFetchExecutor(executor)
.build();
}
创建数据源的数据工厂
@Override
public DataSource create() {
celebrityDataSource = new CelebrityDataSource(apicallInterface, params);
celebrityData.postValue(celebrityDataSource);
return celebrityDataSource;
}
改造API调用:
Call<CelebrityList> getCelebrityList(@Query("categoryId") String categoryId,
@Query("professionId") String professionId,
@Query("page") String pageNumber,
@Query("name") String searchKey);
数据源Api回调:
apicallInterface.getCelebrityList(requestParams.getCategoryId(), "", "1", "").enqueue(new Callback<CelebrityList>() {
@Override
public void onResponse(Call<CelebrityList> call, Response<CelebrityList> response) {
if (response.isSuccessful()) {
initialLoading.postValue(NetworkState.LOADED);
networkState.postValue(NetworkState.LOADED);
if (!response.body().getData().isEmpty()) {
callback.onResult(response.body().getData(), null, "2");
} else {
networkState.postValue(new NetworkState(NetworkState.Status.SUCCESS, "No more results"));
}
} else {
initialLoading.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
networkState.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
}
}
您需要将搜索关键字保留在实时数据中,以便分页列表可以在更改时更改。所以在你的视图模型中,定义:
public MutableLiveData<String> filterTextAll = new MutableLiveData<>();
由于页面列表也被定义为 LiveData,这可以借助转换来完成。转换 class 为您提供了可以更改 LiveData 对象中的值的函数。 swithMap 函数 returns 一个新的 LiveData 对象而不是一个值,在您的情况下,通过在引擎盖下创建新的数据源,切换搜索键以获取与搜索键对应的 pagedList 对象。
pagedListLiveData = Transformations.switchMap(filterTextAll, input -> {
MyDataSourceFactory myDataSourceFactory = new MyDataSourceFactory(executor,input);
myDataSource = myDataSourceFactory.getMyDataSourceMutableLiveData();
networkState = Transformations.switchMap(myDataSource,
dataSource -> dataSource.getNetworkState());
return (new LivePagedListBuilder(myDataSourceFactory, pagedListConfig))
.setFetchExecutor(executor)
.build();
});
您可以更改 DataSourceFactory 和 DataSource 构造函数以添加 searchKey 参数:
public class MyDataSourceFactory extends DataSource.Factory {
MutableLiveData<MyDataSource> myDataSourceMutableLiveData;
private MyDataSource myDataSource;
private Executor executor;
private String searchKey;
public MyDataSourceFactory(Executor executor , String searchKey) {
this.executor= executor;
this.searchKey= searchKey;
this.myDataSourceMutableLiveData= new MutableLiveData<>();
}
@Override
public DataSource create() {
//*notice: It's important that everytime a DataSource factory create() is invoked a new DataSource instance is created
myDataSource= new MyDataSource(executor, searchKey);
myDataSourceMutableLiveData.postValue(myDataSource);
return myDataSource;
}
public MutableLiveData<MyDataSource> getMyDataSourceMutableLiveData() {
return myDataSourceMutableLiveData;
}
public MyDataSource getMyDataSource() {
return myDataSource;
}
}
对 DataSource 构造函数执行与上面相同的操作,以传递 searchKey 以在 api 调用中使用。 还有一件事仍然存在,在你的 Activity/Fragment (lifeCycleOwner) 中设置 filterTextAll mutableLiveData 的值,每当搜索键更改被触发时,比如触发 searchview onQueryTextChange 或你喜欢的任何事件。
private void performSearch(String searchKey) {
// TODO: Perform the search and update the UI to display the results.
myViewModel.filterTextAll.setValue(searchKey);
myViewModel.pagedListLiveData.observe(owner, new Observer<PagedList<MyItem>>() {
@Override
public void onChanged(PagedList<MyItem> myItems) {
myAdapter.submitList(myItems);
}
});
myViewModel.networkState.observe(owner, new Observer<NetworkState>() {
@Override
public void onChanged(NetworkState networkState) {
myAdapter.setNetworkState(networkState);
}
});
myRecyclerView.setAdapter(myAdapter);
}