Java tutorial
/* ownCloud Android client application * Copyright (C) 2012-2014 ownCloud Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * */ package com.digitalarx.android.ui.preview; import java.lang.ref.WeakReference; import android.accounts.Account; import android.annotation.SuppressLint; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.BitmapFactory.Options; import android.graphics.Point; import android.os.AsyncTask; import android.os.Bundle; import android.support.v4.app.FragmentStatePagerAdapter; import android.view.Display; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnTouchListener; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.ProgressBar; import android.widget.TextView; import com.actionbarsherlock.view.Menu; import com.actionbarsherlock.view.MenuInflater; import com.actionbarsherlock.view.MenuItem; import com.digitalarx.android.R; import com.digitalarx.android.datamodel.OCFile; import com.digitalarx.android.files.FileMenuFilter; import com.digitalarx.android.ui.dialog.ConfirmationDialogFragment; import com.digitalarx.android.ui.dialog.RemoveFileDialogFragment; import com.digitalarx.android.ui.fragment.FileFragment; import com.digitalarx.android.utils.Log_OC; /** * This fragment shows a preview of a downloaded image. * * Trying to get an instance with NULL {@link OCFile} or ownCloud {@link Account} values will produce an {@link IllegalStateException}. * * If the {@link OCFile} passed is not downloaded, an {@link IllegalStateException} is generated on instantiation too. * * @author David A. Velasco */ public class PreviewImageFragment extends FileFragment { public static final String EXTRA_FILE = "FILE"; public static final String EXTRA_ACCOUNT = "ACCOUNT"; private View mView; private Account mAccount; private ImageView mImageView; private TextView mMessageView; private ProgressBar mProgressWheel; public Bitmap mBitmap = null; private static final String TAG = PreviewImageFragment.class.getSimpleName(); private boolean mIgnoreFirstSavedState; /** * Creates a fragment to preview an image. * * When 'imageFile' or 'ocAccount' are null * * @param imageFile An {@link OCFile} to preview as an image in the fragment * @param ocAccount An ownCloud account; needed to start downloads * @param ignoreFirstSavedState Flag to work around an unexpected behaviour of {@link FragmentStatePagerAdapter}; TODO better solution */ public PreviewImageFragment(OCFile fileToDetail, Account ocAccount, boolean ignoreFirstSavedState) { super(fileToDetail); mAccount = ocAccount; mIgnoreFirstSavedState = ignoreFirstSavedState; } /** * Creates an empty fragment for image previews. * * MUST BE KEPT: the system uses it when tries to reinstantiate a fragment automatically (for instance, when the device is turned a aside). * * DO NOT CALL IT: an {@link OCFile} and {@link Account} must be provided for a successful construction */ public PreviewImageFragment() { super(); mAccount = null; mIgnoreFirstSavedState = false; } /** * {@inheritDoc} */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setHasOptionsMenu(true); } /** * {@inheritDoc} */ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { super.onCreateView(inflater, container, savedInstanceState); mView = inflater.inflate(R.layout.preview_image_fragment, container, false); mImageView = (ImageView) mView.findViewById(R.id.image); mImageView.setVisibility(View.GONE); mView.setOnTouchListener((OnTouchListener) getActivity()); mMessageView = (TextView) mView.findViewById(R.id.message); mMessageView.setVisibility(View.GONE); mProgressWheel = (ProgressBar) mView.findViewById(R.id.progressWheel); mProgressWheel.setVisibility(View.VISIBLE); return mView; } /** * {@inheritDoc} */ @Override public void onAttach(Activity activity) { super.onAttach(activity); if (!(activity instanceof OnTouchListener)) { throw new ClassCastException( activity.toString() + " must implement " + OnTouchListener.class.getSimpleName()); } } /** * {@inheritDoc} */ @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); if (savedInstanceState != null) { if (!mIgnoreFirstSavedState) { OCFile file = (OCFile) savedInstanceState.getParcelable(PreviewImageFragment.EXTRA_FILE); setFile(file); mAccount = savedInstanceState.getParcelable(PreviewImageFragment.EXTRA_ACCOUNT); } else { mIgnoreFirstSavedState = false; } } if (getFile() == null) { throw new IllegalStateException("Instanced with a NULL OCFile"); } if (mAccount == null) { throw new IllegalStateException("Instanced with a NULL ownCloud Account"); } if (!getFile().isDown()) { throw new IllegalStateException("There is no local file to preview"); } } /** * {@inheritDoc} */ @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putParcelable(PreviewImageFragment.EXTRA_FILE, getFile()); outState.putParcelable(PreviewImageFragment.EXTRA_ACCOUNT, mAccount); } @Override public void onStart() { super.onStart(); if (getFile() != null) { BitmapLoader bl = new BitmapLoader(mImageView, mMessageView, mProgressWheel); bl.execute(new String[] { getFile().getStoragePath() }); } } /** * {@inheritDoc} */ @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { super.onCreateOptionsMenu(menu, inflater); inflater.inflate(R.menu.file_actions_menu, menu); } /** * {@inheritDoc} */ @Override public void onPrepareOptionsMenu(Menu menu) { super.onPrepareOptionsMenu(menu); if (mContainerActivity.getStorageManager() != null) { // Update the file setFile(mContainerActivity.getStorageManager().getFileById(getFile().getFileId())); FileMenuFilter mf = new FileMenuFilter(getFile(), mContainerActivity.getStorageManager().getAccount(), mContainerActivity, getSherlockActivity()); mf.filter(menu); } // additional restriction for this fragment // TODO allow renaming in PreviewImageFragment MenuItem item = menu.findItem(R.id.action_rename_file); if (item != null) { item.setVisible(false); item.setEnabled(false); } // additional restriction for this fragment // TODO allow refresh file in PreviewImageFragment item = menu.findItem(R.id.action_sync_file); if (item != null) { item.setVisible(false); item.setEnabled(false); } } /** * {@inheritDoc} */ @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_share_file: { mContainerActivity.getFileOperationsHelper().shareFileWithLink(getFile()); return true; } case R.id.action_unshare_file: { mContainerActivity.getFileOperationsHelper().unshareFileWithLink(getFile()); return true; } case R.id.action_open_file_with: { openFile(); return true; } case R.id.action_remove_file: { RemoveFileDialogFragment dialog = RemoveFileDialogFragment.newInstance(getFile()); dialog.show(getFragmentManager(), ConfirmationDialogFragment.FTAG_CONFIRMATION); return true; } case R.id.action_see_details: { seeDetails(); return true; } case R.id.action_send_file: { mContainerActivity.getFileOperationsHelper().sendDownloadedFile(getFile()); return true; } case R.id.action_sync_file: { mContainerActivity.getFileOperationsHelper().syncFile(getFile()); return true; } default: return false; } } private void seeDetails() { mContainerActivity.showDetails(getFile()); } @Override public void onResume() { super.onResume(); } @Override public void onPause() { super.onPause(); } @Override public void onDestroy() { if (mBitmap != null) { mBitmap.recycle(); } super.onDestroy(); } /** * Opens the previewed image with an external application. */ private void openFile() { mContainerActivity.getFileOperationsHelper().openFile(getFile()); finish(); } private class BitmapLoader extends AsyncTask<String, Void, Bitmap> { /** * Weak reference to the target {@link ImageView} where the bitmap will be loaded into. * * Using a weak reference will avoid memory leaks if the target ImageView is retired from memory before the load finishes. */ private final WeakReference<ImageView> mImageViewRef; /** * Weak reference to the target {@link TextView} where error messages will be written. * * Using a weak reference will avoid memory leaks if the target ImageView is retired from memory before the load finishes. */ private final WeakReference<TextView> mMessageViewRef; /** * Weak reference to the target {@link Progressbar} shown while the load is in progress. * * Using a weak reference will avoid memory leaks if the target ImageView is retired from memory before the load finishes. */ private final WeakReference<ProgressBar> mProgressWheelRef; /** * Error message to show when a load fails */ private int mErrorMessageId; /** * Constructor. * * @param imageView Target {@link ImageView} where the bitmap will be loaded into. */ public BitmapLoader(ImageView imageView, TextView messageView, ProgressBar progressWheel) { mImageViewRef = new WeakReference<ImageView>(imageView); mMessageViewRef = new WeakReference<TextView>(messageView); mProgressWheelRef = new WeakReference<ProgressBar>(progressWheel); } @SuppressWarnings("deprecation") @SuppressLint({ "NewApi", "NewApi", "NewApi" }) // to avoid Lint errors since Android SDK r20 @Override protected Bitmap doInBackground(String... params) { Bitmap result = null; if (params.length != 1) return result; String storagePath = params[0]; try { // set desired options that will affect the size of the bitmap BitmapFactory.Options options = new Options(); options.inScaled = true; options.inPurgeable = true; if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1) { options.inPreferQualityOverSpeed = false; } if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) { options.inMutable = false; } // make a false load of the bitmap - just to be able to read outWidth, outHeight and outMimeType options.inJustDecodeBounds = true; BitmapFactory.decodeFile(storagePath, options); int width = options.outWidth; int height = options.outHeight; int scale = 1; Display display = getActivity().getWindowManager().getDefaultDisplay(); Point size = new Point(); int screenWidth; int screenHeight; if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB_MR2) { display.getSize(size); screenWidth = size.x; screenHeight = size.y; } else { screenWidth = display.getWidth(); screenHeight = display.getHeight(); } if (width > screenWidth) { // second try to scale down the image , this time depending upon the screen size scale = (int) Math.floor((float) width / screenWidth); } if (height > screenHeight) { scale = Math.max(scale, (int) Math.floor((float) height / screenHeight)); } options.inSampleSize = scale; // really load the bitmap options.inJustDecodeBounds = false; // the next decodeFile call will be real result = BitmapFactory.decodeFile(storagePath, options); //Log_OC.d(TAG, "Image loaded - width: " + options.outWidth + ", loaded height: " + options.outHeight); if (result == null) { mErrorMessageId = R.string.preview_image_error_unknown_format; Log_OC.e(TAG, "File could not be loaded as a bitmap: " + storagePath); } } catch (OutOfMemoryError e) { mErrorMessageId = R.string.preview_image_error_unknown_format; Log_OC.e(TAG, "Out of memory occured for file " + storagePath, e); } catch (NoSuchFieldError e) { mErrorMessageId = R.string.common_error_unknown; Log_OC.e(TAG, "Error from access to unexisting field despite protection; file " + storagePath, e); } catch (Throwable t) { mErrorMessageId = R.string.common_error_unknown; Log_OC.e(TAG, "Unexpected error loading " + getFile().getStoragePath(), t); } return result; } @Override protected void onPostExecute(Bitmap result) { hideProgressWheel(); if (result != null) { showLoadedImage(result); } else { showErrorMessage(); } } private void showLoadedImage(Bitmap result) { if (mImageViewRef != null) { final ImageView imageView = mImageViewRef.get(); if (imageView != null) { imageView.setImageBitmap(result); imageView.setVisibility(View.VISIBLE); mBitmap = result; } // else , silently finish, the fragment was destroyed } if (mMessageViewRef != null) { final TextView messageView = mMessageViewRef.get(); if (messageView != null) { messageView.setVisibility(View.GONE); } // else , silently finish, the fragment was destroyed } } private void showErrorMessage() { if (mImageViewRef != null) { final ImageView imageView = mImageViewRef.get(); if (imageView != null) { // shows the default error icon imageView.setVisibility(View.VISIBLE); } // else , silently finish, the fragment was destroyed } if (mMessageViewRef != null) { final TextView messageView = mMessageViewRef.get(); if (messageView != null) { messageView.setText(mErrorMessageId); messageView.setVisibility(View.VISIBLE); } // else , silently finish, the fragment was destroyed } } private void hideProgressWheel() { if (mProgressWheelRef != null) { final ProgressBar progressWheel = mProgressWheelRef.get(); if (progressWheel != null) { progressWheel.setVisibility(View.GONE); } } } } /** * Helper method to test if an {@link OCFile} can be passed to a {@link PreviewImageFragment} to be previewed. * * @param file File to test if can be previewed. * @return 'True' if the file can be handled by the fragment. */ public static boolean canBePreviewed(OCFile file) { return (file != null && file.isImage()); } /** * Finishes the preview */ private void finish() { Activity container = getActivity(); container.finish(); } }