Java tutorial
/* * Copyright 2016 Niklas Schelten * * 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.raspi.chatapp.ui.image; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.os.Build; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v7.app.ActionBar; import android.support.v7.app.AppCompatActivity; import android.util.DisplayMetrics; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.view.animation.Animation; import android.view.animation.AnimationUtils; import android.widget.ImageView; import android.widget.TextView; import com.ortiz.touch.TouchImageView; import com.raspi.chatapp.R; import com.raspi.chatapp.ui.util.image.AsyncDrawable; import com.raspi.chatapp.ui.util.message_array.ImageMessage; /** * A simple {@link Fragment} subclass. * Activities that contain this fragment must implement the * {@link SingleImageFragment.OnFragmentInteractionListener} interface * to handle interaction events. * Use the {@link SingleImageFragment#newInstance} factory method to * create an instance of this fragment. */ public class SingleImageFragment extends Fragment { private static final String VIEW_PAGE_ITEM = "com.raspi.chatapp.ui.util" + ".image.SingleImageFragment.currentItem"; private int viewPagerPosition = -1; private boolean init = true; private boolean overlayActive = true; private ViewPager viewPager; private OnFragmentInteractionListener mListener; /** * Use this factory method to create a new instance of * this fragment using the provided parameters. * * @return A new instance of fragment SingleImageFragment. */ public static SingleImageFragment newInstance() { SingleImageFragment fragment = new SingleImageFragment(); fragment.setArguments(new Bundle()); return fragment; } public SingleImageFragment() { // Required empty public constructor } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (savedInstanceState != null) { viewPagerPosition = savedInstanceState.getInt(VIEW_PAGE_ITEM, 0); } ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar(); actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true); } @Override public void onResume() { super.onResume(); if (init) initUI(); else if (viewPagerPosition != -1) viewPager.setCurrentItem(viewPagerPosition); init = false; } @Override public void onPause() { viewPagerPosition = viewPager.getCurrentItem(); super.onPause(); } private void initUI() { // set the actionBars background to transparent ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar(); actionBar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.action_bar_transparent))); // set the statusBar color if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) getActivity().getWindow().setStatusBarColor(getResources().getColor(R.color.action_bar_transparent)); TextView chatName = (TextView) getActivity().findViewById(R.id.chat_name); chatName.setText(mListener.getChatName()); // get the imageView and load the image in the background viewPager = ((ViewPager) getActivity().findViewById(R.id.image)); viewPager.setAdapter(new ImagePagerAdapter()); viewPager.setPageTransformer(true, new DepthPageTransformer()); if (viewPagerPosition == -1) viewPager.setCurrentItem(mListener.getCurrent()); else viewPager.setCurrentItem(viewPagerPosition); viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { updateInfo(position); } @Override public void onPageScrollStateChanged(int state) { } }); showOverlay(true); updateInfo(viewPager.getCurrentItem()); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: if (getActivity().getSupportFragmentManager().getBackStackEntryCount() == 0) getActivity().finish(); else getActivity().getSupportFragmentManager().popBackStack(); return true; } return super.onOptionsItemSelected(item); } private void updateInfo(int pos) { // set the correct title ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar(); actionBar.setTitle(String.format(getResources().getString(R.string.single_image_view_title), pos + 1, mListener.getCount())); // set the description TextView description = (TextView) getActivity().findViewById(R.id.description); description.setText(mListener.getImageAtIndex(pos).description); // make it gone if there is none for the layout to be smaller, and, // therefore, the transparent background if (description.getText() == null || description.getText().toString().isEmpty()) description.setVisibility(View.GONE); else description.setVisibility(View.VISIBLE); // update the time of the message TextView dateTime = (TextView) getActivity().findViewById(R.id.date); dateTime.setText(String.format(getResources().getString(R.string.date_and_time), mListener.getImageAtIndex(mListener.getCurrent()).time)); } private void showOverlay(boolean active) { final View imageInfo = getActivity().findViewById(R.id.image_info); Animation anim; if (active) { View decorView = getActivity().getWindow().getDecorView(); int uiOptions = View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_STABLE; decorView.setSystemUiVisibility(uiOptions); anim = AnimationUtils.loadAnimation(getContext(), R.anim.bottom_in); anim.setDuration(300); imageInfo.setVisibility(View.VISIBLE); imageInfo.startAnimation(anim); } else { View decorView = getActivity().getWindow().getDecorView(); int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_STABLE; decorView.setSystemUiVisibility(uiOptions); anim = AnimationUtils.loadAnimation(getContext(), R.anim.bottom_out); anim.setDuration(300); anim.setAnimationListener(new Animation.AnimationListener() { @Override public void onAnimationStart(Animation animation) { } @Override public void onAnimationEnd(Animation animation) { imageInfo.setVisibility(View.GONE); } @Override public void onAnimationRepeat(Animation animation) { } }); imageInfo.startAnimation(anim); } overlayActive = active; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // set the status bar color if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { getActivity().getWindow().setStatusBarColor(Color.BLACK); } setHasOptionsMenu(true); // Inflate the layout for this fragment return inflater.inflate(R.layout.fragment_single_image, container, false); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { menu.clear(); inflater.inflate(R.menu.menu_single_image, menu); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(VIEW_PAGE_ITEM, viewPager.getCurrentItem()); } @Override public void onAttach(Context context) { super.onAttach(context); if (context instanceof OnFragmentInteractionListener) { mListener = (OnFragmentInteractionListener) context; } else { throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener"); } } @Override public void onDetach() { super.onDetach(); mListener = null; } private class DepthPageTransformer implements ViewPager.PageTransformer { private static final float MIN_SCALE = 0.5f; @Override public void transformPage(View page, float position) { int width = page.getWidth(); // offscreen to the left if (position < -1) page.setAlpha(0); else if (position <= 0) {// moving to the left page.setAlpha(1); page.setTranslationX(0); page.setScaleX(1); page.setScaleY(1); } else if (position <= 1) {// moving to the right page.setAlpha(1 - position); page.setTranslationX(width * -position); float scale = MIN_SCALE + (1 - MIN_SCALE) * (1 - Math.abs(position)); page.setScaleX(scale); page.setScaleY(scale); } else// offscreen to the right page.setAlpha(0); } } private class ImagePagerAdapter extends PagerAdapter { @Override public int getCount() { return mListener.getCount(); } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public Object instantiateItem(ViewGroup container, int position) { TouchImageView imageView = new TouchImageView(getContext()); imageView.setScaleType(ImageView.ScaleType.FIT_CENTER); // decode the file into a bitmap and show it afterwards ImageMessage msg = mListener.getImageAtIndex(position); final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(msg.file, options); DisplayMetrics metrics = new DisplayMetrics(); getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics); // Calculate inSampleSize options.inSampleSize = AsyncDrawable.calculateInSampleSize(options, metrics.widthPixels, metrics.heightPixels, true); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; Bitmap bitmap = BitmapFactory.decodeFile(msg.file, options); imageView.setImageBitmap(bitmap); imageView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { showOverlay(!overlayActive); } }); container.addView(imageView, 0); return imageView; } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((ImageView) object); } } /** * This interface must be implemented by activities that contain this * fragment to allow an interaction in this fragment to be communicated * to the activity and potentially other fragments contained in that * activity. * <p/> * See the Android Training lesson <a href= * "http://developer.android.com/training/basics/fragments/communicating.html" * >Communicating with Other Fragments</a> for more information. */ public interface OnFragmentInteractionListener { int getCount(); ImageMessage getImageAtIndex(int index); int getCurrent(); String getChatName(); } }