Android
Paginierung in RecyclerView
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Einführung
Paginierung ist ein häufiges Problem bei vielen mobilen Apps, die mit Datenlisten umgehen müssen. Die meisten mobilen Apps nutzen nun das "Endlos-Seiten" -Modell, bei dem das Scrollen automatisch in neuen Inhalt geladen wird. CWAC Endless Adapter macht es sehr einfach, dieses Muster in Android-Anwendungen zu verwenden
MainActivity.java
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private Toolbar toolbar;
private TextView tvEmptyView;
private RecyclerView mRecyclerView;
private DataAdapter mAdapter;
private LinearLayoutManager mLayoutManager;
private int mStart=0,mEnd=20;
private List<Student> studentList;
private List<Student> mTempCheck;
public static int pageNumber;
public int total_size=0;
protected Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pageNumber = 1;
toolbar = (Toolbar) findViewById(R.id.toolbar);
tvEmptyView = (TextView) findViewById(R.id.empty_view);
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
studentList = new ArrayList<>();
mTempCheck=new ArrayList<>();
handler = new Handler();
if (toolbar != null) {
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Android Students");
}
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new DataAdapter(studentList, mRecyclerView);
mRecyclerView.setAdapter(mAdapter);
GetGroupData("" + mStart, "" + mEnd);
mAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
@Override
public void onLoadMore() {
if( mTempCheck.size()> 0) {
studentList.add(null);
mAdapter.notifyItemInserted(studentList.size() - 1);
int start = pageNumber * 20;
start = start + 1;
++ pageNumber;
mTempCheck.clear();
GetData("" + start,""+ mEnd);
}
}
});
}
public void GetData(final String LimitStart, final String LimitEnd) {
Map<String, String> params = new HashMap<>();
params.put("LimitStart", LimitStart);
params.put("Limit", LimitEnd);
Custom_Volly_Request jsonObjReq = new Custom_Volly_Request(Request.Method.POST,
"Your php file link", params,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d("ResponseSuccess",response.toString());
// handle the data from the servoce
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("ResponseErrorVolly: " + error.getMessage());
}});
}
// load initial data
private void loadData(int start,int end,boolean notifyadapter) {
for (int i = start; i <= end; i++) {
studentList.add(new Student("Student " + i, "androidstudent" + i + "@gmail.com"));
if(notifyadapter)
mAdapter.notifyItemInserted(studentList.size());
}
}
}
OnLoadMoreListener.java
öffentliche Schnittstelle OnLoadMoreListener {void onLoadMore (); }
DataAdapter.java
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
public class DataAdapter extends RecyclerView.Adapter {
private final int VIEW_ITEM = 1;
private final int VIEW_PROG = 0;
private List<Student> studentList;
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
private boolean loading;
private OnLoadMoreListener onLoadMoreListener;
public DataAdapter(List<Student> students, RecyclerView recyclerView) {
studentList = students;
if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (! loading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (onLoadMoreListener != null) {
onLoadMoreListener.onLoadMore();
}
loading = true;
}
}
});
}
}
@Override
public int getItemViewType(int position) {
return studentList.get(position) != null ? VIEW_ITEM : VIEW_PROG;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder vh;
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_row, parent, false);
vh = new StudentViewHolder(v);
} else {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.progress_item, parent, false);
vh = new ProgressViewHolder(v);
}
return vh;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof StudentViewHolder) {
Student singleStudent=studentList.get(position);
((StudentViewHolder) holder).tvName.setText(singleStudent.getName());
((StudentViewHolder) holder).tvEmailId.setText(singleStudent.getEmailId());
((StudentViewHolder) holder).student= singleStudent;
} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
}
}
public void setLoaded(boolean state) {
loading = state;
}
@Override
public int getItemCount() {
return studentList.size();
}
public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
this.onLoadMoreListener = onLoadMoreListener;
}
//
public static class StudentViewHolder extends RecyclerView.ViewHolder {
public TextView tvName;
public TextView tvEmailId;
public Student student;
public StudentViewHolder(View v) {
super(v);
tvName = (TextView) v.findViewById(R.id.tvName);
tvEmailId = (TextView) v.findViewById(R.id.tvEmailId);
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;
public ProgressViewHolder(View v) {
super(v);
progressBar = (ProgressBar) v.findViewById(R.id.progressBar1);
}
}
}
Modified text is an extract of the original Stack Overflow Documentation
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