Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * * 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.huewu.pla.lib; import android.content.Context; 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.AdapterView; import android.widget.FrameLayout; import android.widget.LinearLayout; import android.widget.ListAdapter; import android.widget.ProgressBar; import android.widget.TextView; /** * Static library support version of the framework's * {@link android.app.ListFragment}. Used to write apps that run on platforms * prior to Android 3.0. When running on Android 3.0 or above, this * implementation is still used; it does not try to switch to the framework's * implementation. See the framework SDK documentation for a class overview. */ public class MultiColumnListFragment extends Fragment { static final int INTERNAL_EMPTY_ID = 0x00ff0001; static final int INTERNAL_PROGRESS_CONTAINER_ID = 0x00ff0002; static final int INTERNAL_LIST_CONTAINER_ID = 0x00ff0003; final private Handler mHandler = new Handler(); final private Runnable mRequestFocus = new Runnable() { @Override public void run() { mList.focusableViewAvailable(mList); } }; final private AdapterView.OnItemClickListener mOnClickListener = new AdapterView.OnItemClickListener() { @Override public void onItemClick(final AdapterView<?> parent, final View v, final int position, final long id) { onListItemClick((MultiColumnListView) parent, v, position, id); } }; ListAdapter mAdapter; MultiColumnListView mList; View mEmptyView; TextView mStandardEmptyView; View mProgressContainer; View mListContainer; CharSequence mEmptyText; boolean mListShown; public MultiColumnListFragment() { } /** * Get the ListAdapter associated with this activity's ListView. */ public ListAdapter getListAdapter() { return mAdapter; } /** * Get the activity's list view widget. */ public MultiColumnListView getListView() { ensureList(); return mList; } /** * Get the cursor row ID of the currently selected list item. */ public long getSelectedItemId() { ensureList(); return mList.getSelectedItemId(); } /** * Get the position of the currently selected list item. */ public int getSelectedItemPosition() { ensureList(); return mList.getSelectedItemPosition(); } /** * 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(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 MultiColumnListView lv = createMultiColumnListView(context, inflater); 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; } /** * Detach from list view. */ @Override public void onDestroyView() { mHandler.removeCallbacks(mRequestFocus); mList = null; mListShown = false; mEmptyView = mProgressContainer = mListContainer = null; mStandardEmptyView = 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(final MultiColumnListView l, final View v, final int position, final long id) { } /** * Attach to list view once the view hierarchy has been created. */ @Override public void onViewCreated(final View view, final Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); ensureList(); } /** * 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(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; } /** * Provide the cursor for the list view. */ public void setListAdapter(final ListAdapter 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); } } } /** * 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); } /** * Set the currently selected list item to the specified position with the * adapter's data * * @param position */ public void setSelection(final int position) { ensureList(); mList.setSelection(position); } protected MultiColumnListView createMultiColumnListView(final Context context, final LayoutInflater inflater) { return new MultiColumnListView(context); } 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 MultiColumnListView) { mList = (MultiColumnListView) 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); final View rawListView = root.findViewById(android.R.id.list); if (!(rawListView instanceof MultiColumnListView)) { if (rawListView == null) throw new RuntimeException("Your content must have a MultiColumnListView 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 MultiColumnListView class"); } mList = (MultiColumnListView) rawListView; if (mEmptyView != null) { mList.setEmptyView(mEmptyView); } else if (mEmptyText != null) { mStandardEmptyView.setText(mEmptyText); mList.setEmptyView(mStandardEmptyView); } } mListShown = true; mList.setOnItemClickListener(mOnClickListener); if (mAdapter != null) { final ListAdapter 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); } /** * 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); } } }