Java tutorial
/* * Copyright (C) 2013 AChep@xda <artemchep@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 com.ekuater.labelchat.ui.fragment.userInfo; import android.app.Activity; import android.os.Bundle; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.FrameLayout; import android.widget.LinearLayout; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.RelativeLayout; import android.widget.ScrollView; import android.widget.Space; import com.ekuater.labelchat.R; /** * Little header fragment. * <p/> * <b>Important</b>: Use {@link android.R.id#background} to specify background view and * {@link android.R.id#title} to specify view on top of the header * (for example: a shadow for {@code ActionBar}). * <p/> * Created by AChep@xda <artemchep@gmail.com> */ public abstract class HeaderFragment extends Fragment { private static final String TAG = "HeaderFragment"; public static final int HEADER_BACKGROUND_SCROLL_NORMAL = 0; public static final int HEADER_BACKGROUND_SCROLL_PARALLAX = 1; public static final int HEADER_BACKGROUND_SCROLL_STATIC = 2; private FrameLayout mFrameLayout; // header private View mHeader; private View mHeaderHeader; private View mHeaderBackground; private View mCover; private int mHeaderHeight; private int mHeaderScroll; private int mHeaderBackgroundScrollMode = HEADER_BACKGROUND_SCROLL_NORMAL; private Space mFakeHeader; private boolean isListViewEmpty; // listeners private AbsListView.OnScrollListener mOnScrollListener; private OnHeaderScrollChangedListener mOnHeaderScrollChangedListener; public interface OnHeaderScrollChangedListener { public void onHeaderScrollChanged(float progress, int height, int scroll); } public void setOnHeaderScrollChangedListener(OnHeaderScrollChangedListener listener) { mOnHeaderScrollChangedListener = listener; } public void setHeaderBackgroundScrollMode(int scrollMode) { mHeaderBackgroundScrollMode = scrollMode; } public View getmCover() { return mCover; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { final Activity activity = getActivity(); assert activity != null; mFrameLayout = new FrameLayout(activity); mCover = onCoverView(inflater, mFrameLayout); mHeader = onCreateHeaderView(inflater, mFrameLayout); mHeaderHeader = mHeader.findViewById(android.R.id.title); mHeaderBackground = mHeader.findViewById(android.R.id.background); assert mHeader.getLayoutParams() != null; mHeaderHeight = mHeader.getLayoutParams().height; mFakeHeader = new Space(activity); mFakeHeader.setLayoutParams(new ListView.LayoutParams(0, mHeaderHeight)); View content = onCreateContentView(inflater, mFrameLayout); if (content instanceof RelativeLayout) { isListViewEmpty = true; final ListView listView = (ListView) content.findViewById(R.id.list); listView.addHeaderView(mFakeHeader); listView.setOnScrollListener(new AbsListView.OnScrollListener() { @Override public void onScrollStateChanged(AbsListView absListView, int scrollState) { if (mOnScrollListener != null) { mOnScrollListener.onScrollStateChanged(absListView, scrollState); } } @Override public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalItemCount) { if (mOnScrollListener != null) { mOnScrollListener.onScroll(absListView, firstVisibleItem, visibleItemCount, totalItemCount); } if (isListViewEmpty) { scrollHeaderTo(0); } else { final View child = absListView.getChildAt(0); assert child != null; scrollHeaderTo(child == mFakeHeader ? child.getTop() : -mHeaderHeight); } } }); } else { // Merge fake header view and content view. final LinearLayout view = new LinearLayout(activity); view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); view.setOrientation(LinearLayout.VERTICAL); view.addView(mFakeHeader); view.addView(content); // Put merged content to ScrollView final NotifyingScrollView scrollView = new NotifyingScrollView(activity); scrollView.addView(view); scrollView.setOnScrollChangedListener(new NotifyingScrollView.OnScrollChangedListener() { @Override public void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt) { scrollHeaderTo(-t); } }); content = scrollView; } mFrameLayout.addView(content); mFrameLayout.addView(mHeader); if (mCover != null) { mFrameLayout.addView(mCover); } // Post initial scroll mFrameLayout.post(new Runnable() { @Override public void run() { scrollHeaderTo(0, true); } }); return mFrameLayout; } private void scrollHeaderTo(int scrollTo) { scrollHeaderTo(scrollTo, false); } private void scrollHeaderTo(int scrollTo, boolean forceChange) { scrollTo = Math.min(Math.max(scrollTo, -mHeaderHeight), 0); if (mHeaderScroll == (mHeaderScroll = scrollTo) & !forceChange) return; setViewTranslationY(mHeader, scrollTo); setViewTranslationY(mHeaderHeader, -scrollTo); switch (mHeaderBackgroundScrollMode) { case HEADER_BACKGROUND_SCROLL_NORMAL: setViewTranslationY(mHeaderBackground, 0); break; case HEADER_BACKGROUND_SCROLL_PARALLAX: setViewTranslationY(mHeaderBackground, -scrollTo / 1.6f); break; case HEADER_BACKGROUND_SCROLL_STATIC: setViewTranslationY(mHeaderBackground, -scrollTo); break; } notifyOnHeaderScrollChangeListener((float) -scrollTo / mHeaderHeight, mHeaderHeight, -scrollTo); } private void setViewTranslationY(View view, float translationY) { if (view != null) view.setTranslationY(translationY); } private void notifyOnHeaderScrollChangeListener(float progress, int height, int scroll) { if (mOnHeaderScrollChangedListener != null) { mOnHeaderScrollChangedListener.onHeaderScrollChanged(progress, height, scroll); } } public abstract View onCreateHeaderView(LayoutInflater inflater, ViewGroup container); public abstract View onCreateContentView(LayoutInflater inflater, ViewGroup container); public abstract View onCoverView(LayoutInflater inflater, ViewGroup container); public void setListViewAdapter(ListView listView, ListAdapter adapter) { isListViewEmpty = adapter == null; listView.setAdapter(null); listView.removeHeaderView(mFakeHeader); listView.addHeaderView(mFakeHeader); listView.setAdapter(adapter); } /** * {@inheritDoc AbsListView#setOnScrollChangedListener} */ public void setListViewOnScrollChangedListener(AbsListView.OnScrollListener listener) { mOnScrollListener = listener; } public View getHeaderView() { return mHeader; } public View getHeaderHeaderView() { return mHeaderHeader; } public View getHeaderBackgroundView() { return mHeaderBackground; } public int getHeaderBackgroundScrollMode() { return mHeaderBackgroundScrollMode; } }