com.amalbit.BottomFragment.java Source code

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Here is the source code for com.amalbit.BottomFragment.java

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/*
 * Copyright 2012 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.amalbit;

import java.util.ArrayList;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.animation.TranslateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.amalbit.twitterlistview.R;
import com.amalbit.view.PullToRefreshListView;
import com.amalbit.view.PullToRefreshListView.OnRefreshListener;

public class BottomFragment extends ListFragment {

    private PullToRefreshListView mListView;
    private LinearLayout mQuickReturnView;
    private int mQuickReturnHeight;

    private static final int STATE_ONSCREEN = 0;
    private static final int STATE_OFFSCREEN = 1;
    private static final int STATE_RETURNING = 2;
    private int mState = STATE_ONSCREEN;
    private int mScrollY;
    private int mMinRawY = 0;

    private TranslateAnimation anim;

    ArrayList<String> alTweets;
    ListAdapter adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.footer_fragment, null);
        mQuickReturnView = (LinearLayout) view.findViewById(R.id.footer);
        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        mListView = (PullToRefreshListView) getListView();
        alTweets = new ArrayList<String>();
        for (int i = 0; i < 50; i++)
            alTweets.add("Tweet Number " + i);

        adapter = new ListAdapter();
        mListView.setAdapter(adapter);
        ((PullToRefreshListView) getListView()).setOnRefreshListener(new OnRefreshListener() {
            @Override
            public void onRefresh() {
                // Do work to refresh the list here.
                new GetDataTask().execute();
            }
        });

        mListView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                mQuickReturnHeight = mQuickReturnView.getHeight();
                mListView.computeScrollY();
            }
        });

        mListView.setOnScrollListener(new OnScrollListener() {
            @SuppressLint("NewApi")
            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

                mScrollY = 0;
                int translationY = 0;

                if (mListView.scrollYIsComputed()) {
                    mScrollY = mListView.getComputedScrollY();
                }

                int rawY = mScrollY;

                switch (mState) {
                case STATE_OFFSCREEN:
                    if (rawY >= mMinRawY) {
                        mMinRawY = rawY;
                    } else {
                        mState = STATE_RETURNING;
                    }
                    translationY = rawY;
                    break;

                case STATE_ONSCREEN:
                    if (rawY > mQuickReturnHeight) {
                        mState = STATE_OFFSCREEN;
                        mMinRawY = rawY;
                    }
                    translationY = rawY;
                    break;

                case STATE_RETURNING:

                    translationY = (rawY - mMinRawY) + mQuickReturnHeight;

                    System.out.println(translationY);
                    if (translationY < 0) {
                        translationY = 0;
                        mMinRawY = rawY + mQuickReturnHeight;
                    }

                    if (rawY == 0) {
                        mState = STATE_ONSCREEN;
                        translationY = 0;
                    }

                    if (translationY > mQuickReturnHeight) {
                        mState = STATE_OFFSCREEN;
                        mMinRawY = rawY;
                    }
                    break;
                }

                /** this can be used if the build is below honeycomb **/
                if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.HONEYCOMB) {
                    anim = new TranslateAnimation(0, 0, translationY, translationY);
                    anim.setFillAfter(true);
                    anim.setDuration(0);
                    mQuickReturnView.startAnimation(anim);
                } else {
                    mQuickReturnView.setTranslationY(translationY);
                }

            }

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }
        });
    }

    private class GetDataTask extends AsyncTask<Void, Void, String[]> {

        @Override
        protected String[] doInBackground(Void... params) {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                ;
            }
            return null;
        }

        @Override
        protected void onPostExecute(String[] result) {
            alTweets.add(0, "New Tweet Added");
            if (alTweets.size() > 50)
                alTweets.remove(alTweets.size() - 1);

            // Call onRefreshComplete when the list has been refreshed.
            mListView.onRefreshComplete();

            super.onPostExecute(result);
        }
    }

    public class ListAdapter extends BaseAdapter {

        @Override
        public int getCount() {
            return alTweets.size();
        }

        @Override
        public Object getItem(int position) {
            return alTweets.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View row = convertView;

            LayoutInflater inflater = (LayoutInflater) getActivity()
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.tweet_cell, parent, false);

            ((TextView) row.findViewById(R.id.tv_tweet)).setText(alTweets.get(position));

            return row;
        }

    }
}