ListView - มาทำ Load More ตอน scroll เพื่อโหลดข้อมูลกันเถอะ

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package com.devahoy.android.scrolltoloadlistview;
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import android.app.ListActivity;
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import android.os.Bundle;
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public class MyActivity extends ListActivity {
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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    }
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}

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package com.devahoy.android.scrolltoloadlistview;
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import android.app.ListActivity;
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import android.os.Bundle;
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import android.widget.ArrayAdapter;
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import android.widget.Toast;
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import java.util.ArrayList;
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import java.util.List;
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public class MyActivity extends ListActivity {
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    private List<String> mTotalData = new ArrayList<String>();
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    private List<String> mCurrentData = new ArrayList<String>();
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    private int mCurrentPage = 1;
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    private int mItemPerRow = 20;
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        for (int i = 1; i <= 300; i++) {
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            mTotalData.add("Item #" + i);
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        }
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        // init first 20 items
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        getData();
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        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
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                android.R.layout.simple_list_item_1, mCurrentData);
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        setListAdapter(adapter);
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    }
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    private void getData() {
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        if (mItemPerRow * mCurrentPage >= mTotalData.size()) {
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            Toast.makeText(this, "No Data", Toast.LENGTH_SHORT).show();
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            return;
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        }
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        for (int i = 0; i < mItemPerRow; i++) {
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            mCurrentData.add(mTotalData.get(i + (( mCurrentPage - 1) * mItemPerRow)) );
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        }
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        mCurrentPage += 1;
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    }
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}

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public class MyAct extends ListActivity {
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    ...
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    private boolean isLoadMore = false;
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    private Handler mHandler = new Handler();
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        ...
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        setListAdapter(adapter);
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        getListView().setOnScrollListener(new AbsListView.OnScrollListener() {
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            @Override
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            public void onScrollStateChanged(AbsListView view, int scrollState) {
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            }
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            @Override
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            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
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                int lastInScreen = firstVisibleItem + visibleItemCount;
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                if ((lastInScreen == totalItemCount) && !isLoadMore) {
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                    isLoadMore = true;
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                    mHandler.postDelayed(new Runnable() {
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                        @Override
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                        public void run() {
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                            getData();
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                            adapter.notifyDataSetChanged();
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                            isLoadMore = false;
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                        }
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                    }, 1500);
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                }
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            }
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        });
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    }
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    private void getData() {
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        ...
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    }
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}

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int lastInScreen = firstVisibleItem + visibleItemCount;

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package com.devahoy.android.scrolltoloadlistview;
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import android.app.ListActivity;
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import android.app.ProgressDialog;
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import android.os.Bundle;
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import android.os.Handler;
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import android.widget.AbsListView;
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import android.widget.ArrayAdapter;
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import android.widget.Toast;
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import java.util.ArrayList;
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import java.util.List;
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public class MyAct extends ListActivity {
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    ...
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    private ProgressDialog mLoading;
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        ...
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        mLoading = new ProgressDialog(this);
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        mLoading.setProgressStyle(ProgressDialog.STYLE_SPINNER);
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        mLoading.setMessage("Loading....");
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        ...
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            if ((lastInScreen == totalItemCount) && !isLoadMore) {
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                isLoadMore = true;
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                mLoading.show();
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                mHandler.postDelayed(new Runnable() {
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                    @Override
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                    public void run() {
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                        getData();
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                        adapter.notifyDataSetChanged();
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                        isLoadMore = false;
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                        mLoading.dismiss();
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                    }
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                }, 1500);
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            }
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    }
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    private void getData() {
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        ...
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    }
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}

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mCurrentData.clear();
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getListView().smoothScrollToPosition(0);

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package com.devahoy.android.scrolltoloadlistview;
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import android.app.ListActivity;
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import android.app.ProgressDialog;
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import android.os.Bundle;
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import android.os.Handler;
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import android.util.Log;
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import android.widget.AbsListView;
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import android.widget.ArrayAdapter;
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import android.widget.Toast;
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import java.util.ArrayList;
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import java.util.List;
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public class MyActivity extends ListActivity {
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    private List<String> mTotalData = new ArrayList<String>();
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    private List<String> mCurrentData = new ArrayList<String>();
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    private int mCurrentPage = 1;
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    private int mItemPerRow = 20;
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    private boolean isLoadMore = false;
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    private Handler mHandler = new Handler();
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    private ProgressDialog mLoading;
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        mLoading = new ProgressDialog(this);
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        mLoading.setProgressStyle(ProgressDialog.STYLE_SPINNER);
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        mLoading.setMessage("Loading....");
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        for (int i = 1; i <= 300; i++) {
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            mTotalData.add("Item #" + i);
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        }
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        // init first 20 items
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        getData();
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        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
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                android.R.layout.simple_list_item_1, mCurrentData);
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        setListAdapter(adapter);
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        getListView().setOnScrollListener(new AbsListView.OnScrollListener() {
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            @Override
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            public void onScrollStateChanged(AbsListView view, int scrollState) {
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            }
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            @Override
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            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
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                int lastInScreen = firstVisibleItem + visibleItemCount;
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                Log.d("TEST", "first : " + firstVisibleItem);
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                Log.d("TEST", "visible : " + visibleItemCount);
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                Log.d("TEST", "total : " + totalItemCount);
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                if ((lastInScreen == totalItemCount) && !isLoadMore && (firstVisibleItem != 0)) {
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                    isLoadMore = true;
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                    mLoading.show();
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                    mHandler.postDelayed(new Runnable() {
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                        @Override
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                        public void run() {
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                            getData();
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                            adapter.notifyDataSetChanged();
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                            isLoadMore = false;
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                            mLoading.dismiss();
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                        }
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                    }, 1500);
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                }
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            }
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        });
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    }
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    private void getData() {
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        if (mItemPerRow * mCurrentPage >= mTotalData.size()) {
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            Toast.makeText(this, "No Data", Toast.LENGTH_SHORT).show();
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            return;
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        }
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        for (int i = 0; i < mItemPerRow; i++) {
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            mCurrentData.add(mTotalData.get(i + (( mCurrentPage - 1) * mItemPerRow)) );
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        }
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        mCurrentPage += 1;
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    }
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}