Java tutorial
/* * Copyright 2013 wada811<at.wada811@gmail.com> * * 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 at.wada811.app.fragment; import android.content.Context; import android.os.Build; 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.ViewGroup; import android.view.animation.AnimationUtils; import android.widget.ExpandableListAdapter; import android.widget.ExpandableListView; import android.widget.FrameLayout; import android.widget.LinearLayout; import android.widget.ListAdapter; import android.widget.ProgressBar; import android.widget.TextView; import at.wada811.android.library.R; /** * An fragment that displays an expandable list of items by binding to a data * source implementing the ExpandableListAdapter, and exposes event handlers * when the user selects an item. */ public class ExpandableListFragment extends Fragment implements ExpandableListView.OnGroupCollapseListener, ExpandableListView.OnGroupExpandListener, ExpandableListView.OnGroupClickListener, ExpandableListView.OnChildClickListener { private static final int INTERNAL_EMPTY_ID = R.id.INTERNAL_EMPTY_ID; private static final int INTERNAL_PROGRESS_CONTAINER_ID = R.id.INTERNAL_PROGRESS_CONTAINER_ID; private static final int INTERNAL_LIST_CONTAINER_ID = R.id.INTERNAL_LIST_CONTAINER_ID; private final Handler mHandler = new Handler(); private final Runnable mRequestFocus = new Runnable() { @Override public void run() { mList.focusableViewAvailable(mList); } }; ExpandableListAdapter mAdapter; ExpandableListView mList; View mEmptyView; TextView mStandardEmptyView; View mProgressContainer; View mListContainer; CharSequence mEmptyText; boolean mListShown; public ExpandableListFragment() { } /** * Provide default implementation to return a expandable list view. Subclasses * can override to replace with their own layout. If doing so, the returned * view hierarchy <em>must</em> have a ExpandableListView 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 ExpandableListFragment. In particular, * this is currently the only way to have the built-in indeterminant progress state be shown. * * @param inflater The LayoutInflater object that can be used to inflate any views in the * fragment, * @param container If non-null, this is the parent view that the fragment's UI should be * attached to. The fragment should not add the view itself, but this can be used to * generate the LayoutParams of the view. * @param savedInstanceState If non-null, this fragment is being re-constructed from a previous * saved state as given here. * @return Return the View for the fragment's UI, or null. */ @Override public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) { final Context context = getActivity(); final FrameLayout root = new FrameLayout(context); // ------------------------------------------------------------------ final LinearLayout pframe = new LinearLayout(context); pframe.setId(INTERNAL_PROGRESS_CONTAINER_ID); pframe.setOrientation(LinearLayout.VERTICAL); pframe.setVisibility(View.GONE); pframe.setGravity(Gravity.CENTER); final ProgressBar progress = new ProgressBar(context, null, android.R.attr.progressBarStyleLarge); pframe.addView(progress, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); root.addView(pframe, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); // ------------------------------------------------------------------ final FrameLayout lframe = new FrameLayout(context); lframe.setId(INTERNAL_LIST_CONTAINER_ID); final TextView tv = new TextView(getActivity()); tv.setId(INTERNAL_EMPTY_ID); tv.setGravity(Gravity.CENTER); lframe.addView(tv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); final ExpandableListView lv = new ExpandableListView(getActivity()); lv.setId(android.R.id.list); lv.setDrawSelectorOnTop(false); lframe.addView(lv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); root.addView(lframe, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); // ------------------------------------------------------------------ root.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); return root; } /** * Attach to expandable list view once the view hierarchy has been created. * * @param view The View returned by {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}. * @param savedInstanceState If non-null, this fragment is being re-constructed from a previous * saved state as given here. */ @Override public void onViewCreated(final View view, final Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); ensureList(); } /** * Detach from expandable list view. */ @Override public void onDestroyView() { mHandler.removeCallbacks(mRequestFocus); mList = null; mListShown = false; mEmptyView = mProgressContainer = mListContainer = null; mStandardEmptyView = null; super.onDestroyView(); } @Override public boolean onGroupClick(final ExpandableListView parent, final View v, final int groupPosition, final long id) { return false; } /** * Override this for receiving callbacks when a group has been expanded. * * @param groupPosition The group position that was expanded */ @Override public void onGroupExpand(final int groupPosition) { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.FROYO) { mList.setSelectedGroup(groupPosition); } } /** * Override this for receiving callbacks when a group has been collapsed. * * @param groupPosition The group position that was collapsed */ @Override public void onGroupCollapse(final int groupPosition) { } /** * Override this for receiving callbacks when a child has been clicked. * Callback method to be invoked when a child in this expandable list has been clicked. * * @param parent The ExpandableListView where the click happened * @param v The view within the expandable list/ListView that was clicked * @param groupPosition The group position that contains the child that was clicked * @param childPosition The child position within the group * @param id The row id of the child that was clicked */ @Override public boolean onChildClick(final ExpandableListView parent, final View v, final int groupPosition, final int childPosition, final long id) { return false; } /** * Provide the adapter for the expandable list. */ public void setListAdapter(final ExpandableListAdapter adapter) { final 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); } } } /** * Sets the selection to the specified group. * * @param groupPosition The position of the group that should be selected. */ public void setSelectedGroup(final int groupPosition) { ensureList(); mList.setSelectedGroup(groupPosition); } /** * 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(final int groupPosition, final int childPosition, final boolean shouldExpandGroup) { ensureList(); return mList.setSelectedChild(groupPosition, childPosition, shouldExpandGroup); } /** * Gets the position (in packed position representation) of the currently selected group or * child. * Use getPackedPositionType(long), getPackedPositionGroup(long), and * getPackedPositionChild(long) to unpack the returned packed position. * * @return A packed position representation containing the currently selected group or child's * position and type. */ public long getSelectedPosition() { ensureList(); return mList.getSelectedPosition(); } /** * Gets the ID of the currently selected group or child. * * @return The ID of the currently selected group or child. */ public long getSelectedId() { ensureList(); return mList.getSelectedId(); } /** * Get the activity's expandable list view widget. */ public ExpandableListView getExpandableListView() { ensureList(); return mList; } /** * The default content for a ExpandableListFragment 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(final CharSequence text) { ensureList(); if (mStandardEmptyView == null) { throw new IllegalStateException("Can't be used with a custom content view"); } mStandardEmptyView.setText(text); if (mEmptyText == null) { mList.setEmptyView(mStandardEmptyView); } mEmptyText = text; } /** * 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(final boolean shown) { setListShown(shown, true); } /** * Like {@link #setListShown(boolean)}, but no animation is used when transitioning from the * previous state. */ public void setListShownNoAnimation(final 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(final boolean shown, final boolean animate) { ensureList(); if (mProgressContainer == null) { throw new IllegalStateException("Can't be used with a custom content view"); } if (mListShown == shown) { return; } mListShown = shown; if (shown) { if (animate) { mProgressContainer .startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out)); mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in)); } else { mProgressContainer.clearAnimation(); mListContainer.clearAnimation(); } mProgressContainer.setVisibility(View.GONE); mListContainer.setVisibility(View.VISIBLE); } else { if (animate) { mProgressContainer .startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in)); mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out)); } else { mProgressContainer.clearAnimation(); mListContainer.clearAnimation(); } mProgressContainer.setVisibility(View.VISIBLE); mListContainer.setVisibility(View.GONE); } } /** * Get the ExpandableListAdapter associated with this activity's ExpandableListView. */ public ExpandableListAdapter getExpandableListAdapter() { return mAdapter; } private void ensureList() { if (mList != null) { return; } final 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); } else { mStandardEmptyView.setVisibility(View.GONE); } mProgressContainer = root.findViewById(INTERNAL_PROGRESS_CONTAINER_ID); mListContainer = root.findViewById(INTERNAL_LIST_CONTAINER_ID); 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); } else if (mEmptyText != null) { mStandardEmptyView.setText(mEmptyText); mList.setEmptyView(mStandardEmptyView); } } mListShown = true; // mList.setOnCreateContextMenuListener(this); mList.setOnChildClickListener(this); mList.setOnGroupCollapseListener(this); mList.setOnGroupExpandListener(this); mList.setOnGroupClickListener(this); if (mAdapter != null) { final ExpandableListAdapter adapter = mAdapter; mAdapter = null; setListAdapter(adapter); } else { // We are starting without an adapter, so assume we won't // have our data right away and start with the progress indicator. if (mProgressContainer != null) { setListShown(false, false); } } mHandler.post(mRequestFocus); } }