Java tutorial
/** * Copyright (c) 2012 Todoroo Inc * * See the file "LICENSE" for the full license governing this code. */ package com.todoroo.astrid.activity; import android.os.Bundle; import android.os.Handler; import android.support.v4.app.Fragment; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnCreateContextMenuListener; import android.view.ViewGroup; import android.view.animation.AnimationUtils; import android.widget.AdapterView; import android.widget.ExpandableListAdapter; import android.widget.ExpandableListView; import android.widget.FrameLayout; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.TextView; @SuppressWarnings("nls") public class ExpandableListFragment extends Fragment implements OnCreateContextMenuListener, ExpandableListView.OnChildClickListener, ExpandableListView.OnGroupCollapseListener, ExpandableListView.OnGroupExpandListener { static final int INTERNAL_EMPTY_ID = 0x00ff0001; final private Handler mHandler = new Handler(); final private Runnable mRequestFocus = new Runnable() { public void run() { mList.focusableViewAvailable(mList); } }; final private AdapterView.OnItemClickListener mOnClickListener = new AdapterView.OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { onListItemClick((ListView) parent, v, position, id); } }; ExpandableListAdapter mAdapter; ExpandableListView mList; View mEmptyView; TextView mStandardEmptyView; boolean mSetEmptyText; boolean mListShown; boolean mFinishedStart = false; /** * Provide default implementation to return a simple list view. Subclasses * can override to replace with their own layout. If doing so, the * returned view hierarchy <em>must</em> have a ListView whose id * is {@link android.R.id#list android.R.id.list} and can optionally * have a sibling view id {@link android.R.id#empty android.R.id.empty} * that is to be shown when the list is empty. * * <p>If you are overriding this method with your own custom content, * consider including the standard layout {@link android.R.layout#list_content} * in your layout file, so that you continue to retain all of the standard * behavior of ListFragment. In particular, this is currently the only * way to have the built-in indeterminant progress state be shown. */ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { FrameLayout root = new FrameLayout(getActivity()); TextView tv = new TextView(getActivity()); tv.setId(INTERNAL_EMPTY_ID); tv.setGravity(Gravity.CENTER); root.addView(tv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); ExpandableListView lv = new ExpandableListView(getActivity()); lv.setId(android.R.id.list); lv.setDrawSelectorOnTop(false); root.addView(lv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); ListView.LayoutParams lp = new ListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT); root.setLayoutParams(lp); return root; } /** * Attach to list view once Fragment is ready to run. */ @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); ensureList(); } /** * Detach from list view. */ @Override public void onDestroyView() { mHandler.removeCallbacks(mRequestFocus); mList = null; super.onDestroyView(); } /** * This method will be called when an item in the list is selected. * Subclasses should override. Subclasses can call * getListView().getItemAtPosition(position) if they need to access the * data associated with the selected item. * * @param l The ListView where the click happened * @param v The view that was clicked within the ListView * @param position The position of the view in the list * @param id The row id of the item that was clicked */ public void onListItemClick(ListView l, View v, int position, long id) { // override me } /** * Provide the cursor for the list view. */ public void setListAdapter(ExpandableListAdapter adapter) { boolean hadAdapter = mAdapter != null; mAdapter = adapter; if (mList != null) { mList.setAdapter(adapter); if (!mListShown && !hadAdapter) { // The list was hidden, and previously didn't have an // adapter. It is now time to show it. setListShown(true, getView().getWindowToken() != null); } } } /** * Set the currently selected list item to the specified * position with the adapter's data * * @param position */ public void setSelection(int position) { ensureList(); mList.setSelection(position); } public long getSelectedPosition() { ensureList(); return mList.getSelectedPosition(); } /** * Sets the selection to the specified child. If the child is in a collapsed * group, the group will only be expanded and child subsequently selected if * shouldExpandGroup is set to true, otherwise the method will return false. * * @param groupPosition The position of the group that contains the child. * @param childPosition The position of the child within the group. * @param shouldExpandGroup Whether the child's group should be expanded if * it is collapsed. * @return Whether the selection was successfully set on the child. */ public boolean setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) { ensureList(); return mList.setSelectedChild(groupPosition, childPosition, shouldExpandGroup); } public void setItemChecked(int position, boolean value) { ensureList(); mList.setItemChecked(position, value); } /** * Sets the selection to the specified group. * @param groupPosition The position of the group that should be selected. */ public void setSelectedGroup(int groupPosition) { mList.setSelectedGroup(groupPosition); } public long getSelectedId() { ensureList(); return mList.getSelectedId(); } public ExpandableListView getExpandableListView() { ensureList(); return mList; } /** * The default content for a ListFragment has a TextView that can * be shown when the list is empty. If you would like to have it * shown, call this method to supply the text it should use. */ public void setEmptyText(CharSequence text) { ensureList(); if (mStandardEmptyView == null) { throw new IllegalStateException("Can't be used with a custom content view"); } mStandardEmptyView.setText(text); if (!mSetEmptyText) { mList.setEmptyView(mStandardEmptyView); mSetEmptyText = true; } } /** * Control whether the list is being displayed. You can make it not * displayed if you are waiting for the initial data to show in it. During * this time an indeterminant progress indicator will be shown instead. * * <p>Applications do not normally need to use this themselves. The default * behavior of ListFragment is to start with the list not being shown, only * showing it once an adapter is given with {@link #setListAdapter(ListAdapter)}. * If the list at that point had not been shown, when it does get shown * it will be do without the user ever seeing the hidden state. * * @param shown If true, the list view is shown; if false, the progress * indicator. The initial value is true. */ public void setListShown(boolean shown) { setListShown(shown, true); } /** * Like {@link #setListShown(boolean)}, but no animation is used when * transitioning from the previous state. */ public void setListShownNoAnimation(boolean shown) { setListShown(shown, false); } /** * Control whether the list is being displayed. You can make it not * displayed if you are waiting for the initial data to show in it. During * this time an indeterminant progress indicator will be shown instead. * * @param shown If true, the list view is shown; if false, the progress * indicator. The initial value is true. * @param animate If true, an animation will be used to transition to the * new state. */ private void setListShown(boolean shown, boolean animate) { ensureList(); if (mListShown == shown) { return; } mListShown = shown; if (shown) { if (animate) { mList.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in)); } mList.setVisibility(View.VISIBLE); } else { if (animate) { mList.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out)); } mList.setVisibility(View.GONE); } } /** * Get the ListAdapter associated with this activity's ListView. */ public ExpandableListAdapter getExpandableListAdapter() { return mAdapter; } private void ensureList() { if (mList != null) { return; } View root = getView(); if (root == null) { throw new IllegalStateException("Content view not yet created"); } if (root instanceof ExpandableListView) { mList = (ExpandableListView) root; } else { mStandardEmptyView = (TextView) root.findViewById(INTERNAL_EMPTY_ID); if (mStandardEmptyView == null) { mEmptyView = root.findViewById(android.R.id.empty); } View rawListView = root.findViewById(android.R.id.list); if (!(rawListView instanceof ExpandableListView)) { if (rawListView == null) { throw new RuntimeException("Your content must have a ExpandableListView whose id attribute is " + "'android.R.id.list'"); } throw new RuntimeException("Content has view with id attribute 'android.R.id.list' " + "that is not a ExpandableListView class"); } mList = (ExpandableListView) rawListView; if (mEmptyView != null) { mList.setEmptyView(mEmptyView); } } mListShown = true; mList.setOnItemClickListener(mOnClickListener); if (mAdapter != null) { setListAdapter(mAdapter); } else { // We are starting without an adapter, so assume we won't // have our data right away and start with the progress indicator. setListShown(false, false); } mHandler.post(mRequestFocus); } public void onContentChanged() { View emptyView = getView().findViewById(android.R.id.empty); mList = (ExpandableListView) getView().findViewById(android.R.id.list); if (mList == null) { throw new RuntimeException( "Your content must have a ExpandableListView whose id attribute is " + "'android.R.id.list'"); } if (emptyView != null) { mList.setEmptyView(emptyView); } mList.setOnChildClickListener(this); mList.setOnGroupExpandListener(this); mList.setOnGroupCollapseListener(this); if (mFinishedStart) { setListAdapter(mAdapter); } mFinishedStart = true; } @Override public void onGroupExpand(int groupPosition) { // override me } @Override public void onGroupCollapse(int groupPosition) { // override me } @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { return false; } }