在Android分页库中,可以通过自定义DataSource的方式来释放缓存数据。以下是一个示例代码:
首先,创建一个自定义的DataSource类,继承自PageKeyedDataSource:
public class CustomDataSource extends PageKeyedDataSource {
private static final int PAGE_SIZE = 10;
@Override
public void loadInitial(@NonNull LoadInitialParams params, @NonNull LoadInitialCallback callback) {
// 加载初始数据
List data = fetchData(0, PAGE_SIZE);
callback.onResult(data, null, 1);
}
@Override
public void loadBefore(@NonNull LoadParams params, @NonNull LoadCallback callback) {
// 加载前一页数据
List data = fetchData(params.key, PAGE_SIZE);
Integer adjacentKey = (params.key > 1) ? params.key - 1 : null;
callback.onResult(data, adjacentKey);
}
@Override
public void loadAfter(@NonNull LoadParams params, @NonNull LoadCallback callback) {
// 加载下一页数据
List data = fetchData(params.key, PAGE_SIZE);
Integer adjacentKey = params.key + 1;
callback.onResult(data, adjacentKey);
}
private List fetchData(int page, int pageSize) {
// 从网络或本地数据库中获取数据
// ...
}
}
然后,在Activity或Fragment中,使用PagedList和PagingDataSourceFactory来创建一个PagingDataAdapter,并设置数据:
public class MainActivity extends AppCompatActivity {
private CustomDataSource.Factory dataSourceFactory;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dataSourceFactory = new CustomDataSource.Factory();
PagedList.Config config = new PagedList.Config.Builder()
.setEnablePlaceholders(false)
.setPageSize(CustomDataSource.PAGE_SIZE)
.build();
LiveData> pagedListLiveData = new LivePagedListBuilder<>(dataSourceFactory, config)
.build();
RecyclerView recyclerView = findViewById(R.id.recyclerView);
final DataAdapter adapter = new DataAdapter();
recyclerView.setAdapter(adapter);
pagedListLiveData.observe(this, new Observer>() {
@Override
public void onChanged(PagedList dataItems) {
adapter.submitList(dataItems);
}
});
}
// 在需要释放缓存数据的时候调用
private void invalidateDataSource() {
if (dataSourceFactory != null) {
dataSourceFactory.invalidateDataSource();
}
}
}
最后,在需要释放缓存数据的时候,调用invalidateDataSource()方法来释放缓存数据。这样就可以实现释放缓存数据的功能了。