Java tutorial
/* * @copyright 2013 Philip Warner * @license GNU General Public License * * This file is part of Book Catalogue. * * Book Catalogue is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Book Catalogue 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 Book Catalogue. If not, see <http://www.gnu.org/licenses/>. */ package com.eleybourn.bookcatalogue.filechooser; import java.io.File; import java.util.ArrayList; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.Toast; import com.eleybourn.bookcatalogue.R; import com.eleybourn.bookcatalogue.compat.BookCatalogueActivity; import com.eleybourn.bookcatalogue.filechooser.FileChooserFragment.FileDetails; import com.eleybourn.bookcatalogue.filechooser.FileChooserFragment.PathChangedListener; import com.eleybourn.bookcatalogue.filechooser.FileLister.FileListerListener; import com.eleybourn.bookcatalogue.utils.SimpleTaskQueueProgressFragment; /** * Base class for an Activity to perform file browsing functions consistent with * an Open/Save-As chooser. * * @author pjw */ public abstract class FileChooser extends BookCatalogueActivity implements SimpleTaskQueueProgressFragment.OnAllTasksFinishedListener, SimpleTaskQueueProgressFragment.OnTaskFinishedListener, FileLister.FileListerListener, PathChangedListener { /** Flag indicating nature of this activity */ private boolean mIsSaveDialog = false; /** * Key for member of EXTRAS that specifies the mode of operation of this * dialog */ public static final String EXTRA_MODE = "mode"; /** * Value for member of EXTRAS that specifies the mode of operation of this * dialog */ public static final String EXTRA_MODE_SAVE_AS = "saveAs"; /** * Value for member of EXTRAS that specifies the mode of operation of this * dialog */ public static final String EXTRA_MODE_OPEN = "open"; /** File name for fragment we display */ public static final String EXTRA_FILE_NAME = "fileName"; /** * Accessor * * @return */ public boolean isSaveDialog() { return mIsSaveDialog; } /** Create the fragment we display */ protected abstract FileChooserFragment getChooserFragment(); /** * Initialize this activity */ public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.setContentView(R.layout.file_chooser_base); // Determine the dialog type Bundle extras = getIntent().getExtras(); if (extras == null) { mIsSaveDialog = false; } else { String mode = extras.getString(EXTRA_MODE); if (mode == null) mIsSaveDialog = false; else mIsSaveDialog = mode.equals(EXTRA_MODE_SAVE_AS); } // Get and display the fragment FragmentManager fragmentManager = getSupportFragmentManager(); if (findViewById(R.id.browser_fragment) != null && fragmentManager.findFragmentById(R.id.browser_fragment) == null) { // Create the browser FileChooserFragment frag = getChooserFragment(); // frag.setArguments(getIntent().getExtras()); getSupportFragmentManager().beginTransaction().replace(R.id.browser_fragment, frag).commit(); } // Handle 'Cancel' button findViewById(R.id.cancel).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { finish(); } }); // Handle Open/Save button Button confirm = (Button) findViewById(R.id.confirm); if (mIsSaveDialog) { confirm.setText(R.string.save); confirm.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { handleSave(); } }); } else { confirm.setText(R.string.open); confirm.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { handleOpen(); } }); } } /** * Implemented by subclass to handle a click on the 'Open' button * * @param file * Selected file */ protected abstract void onOpen(File file); /** * Implemented by subclass to handle a click on the 'Save' button * * @param file * Selected file */ protected abstract void onSave(File file); /** * Local handler for 'Open'. Perform basic validation, and pass on. */ private void handleOpen() { Fragment frag = getSupportFragmentManager().findFragmentById(R.id.browser_fragment); if (frag instanceof FileChooserFragment) { FileChooserFragment bf = (FileChooserFragment) frag; File file = bf.getSelectedFile(); if (file == null || !file.exists() || !file.isFile()) { Toast.makeText(this, R.string.please_select_an_existing_file, Toast.LENGTH_LONG).show(); return; } onOpen(file); } } /** * Local handler for 'Save'. Perform basic validation, and pass on. */ private void handleSave() { Fragment frag = getSupportFragmentManager().findFragmentById(R.id.browser_fragment); if (frag instanceof FileChooserFragment) { FileChooserFragment bf = (FileChooserFragment) frag; File file = bf.getSelectedFile(); if (file == null || (file.exists() && !file.isFile())) { Toast.makeText(this, R.string.please_select_a_non_directory, Toast.LENGTH_LONG).show(); return; } onSave(file); } } /** * Called by lister fragment to pass on the list of files. */ @Override public void onGotFileList(File root, ArrayList<FileDetails> list) { FragmentManager fragmentManager = getSupportFragmentManager(); Fragment frag = fragmentManager.findFragmentById(R.id.browser_fragment); if (frag != null && frag instanceof FileListerListener) { ((FileListerListener) frag).onGotFileList(root, list); } } /** * Get an object for building an list of files in background. * @param root * @return */ public abstract FileLister getFileLister(File root); /** * Rebuild the file list in background; gather whatever data is necessary to * ensure fast building of views in the UI thread. * * @param root */ public void onPathChanged(File root) { if (root == null || !root.isDirectory()) return; // Create the background task FileLister lister = getFileLister(root); // Start the task SimpleTaskQueueProgressFragment.runTaskWithProgress(this, R.string.searching_directory_ellipsis, lister, true, 0); } }