Java tutorial
/* * Copyright (C) 2007 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.android.settings; import android.app.Activity; import android.app.LoaderManager; import android.content.ActivityNotFoundException; import android.content.ContentResolver; import android.content.Context; import android.content.Intent; import android.content.Loader; import android.net.Uri; import android.os.Bundle; import android.os.StrictMode; import android.os.SystemProperties; import android.support.annotation.VisibleForTesting; import android.support.v4.content.FileProvider; import android.text.TextUtils; import android.util.Log; import android.widget.Toast; import com.android.settings.users.RestrictedProfileSettings; import java.io.File; import java.util.ArrayList; import java.util.List; /** * The "dialog" that shows from "License" in the Settings app. */ public class SettingsLicenseActivity extends Activity implements LoaderManager.LoaderCallbacks<File> { private static final String TAG = "SettingsLicenseActivity"; private static final String DEFAULT_LICENSE_PATH = "/system/etc/NOTICE.html.gz"; private static final String PROPERTY_LICENSE_PATH = "ro.config.license_path"; private static final int LOADER_ID_LICENSE_HTML_LOADER = 0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); final String licenseHtmlPath = SystemProperties.get(PROPERTY_LICENSE_PATH, DEFAULT_LICENSE_PATH); if (isFilePathValid(licenseHtmlPath)) { showSelectedFile(licenseHtmlPath); } else { showHtmlFromDefaultXmlFiles(); } } @Override public Loader<File> onCreateLoader(int id, Bundle args) { return new LicenseHtmlLoader(this); } @Override public void onLoadFinished(Loader<File> loader, File generatedHtmlFile) { showGeneratedHtmlFile(generatedHtmlFile); } @Override public void onLoaderReset(Loader<File> loader) { } private void showHtmlFromDefaultXmlFiles() { getLoaderManager().initLoader(LOADER_ID_LICENSE_HTML_LOADER, Bundle.EMPTY, this); } @VisibleForTesting Uri getUriFromGeneratedHtmlFile(File generatedHtmlFile) { return FileProvider.getUriForFile(this, RestrictedProfileSettings.FILE_PROVIDER_AUTHORITY, generatedHtmlFile); } private void showGeneratedHtmlFile(File generatedHtmlFile) { if (generatedHtmlFile != null) { showHtmlFromUri(getUriFromGeneratedHtmlFile(generatedHtmlFile)); } else { Log.e(TAG, "Failed to generate."); showErrorAndFinish(); } } private void showSelectedFile(final String path) { if (TextUtils.isEmpty(path)) { Log.e(TAG, "The system property for the license file is empty"); showErrorAndFinish(); return; } final File file = new File(path); if (!isFileValid(file)) { Log.e(TAG, "License file " + path + " does not exist"); showErrorAndFinish(); return; } showHtmlFromUri(Uri.fromFile(file)); } private void showHtmlFromUri(Uri uri) { // Kick off external viewer due to WebView security restrictions; we // carefully point it at HTMLViewer, since it offers to decompress // before viewing. final Intent intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(uri, "text/html"); intent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_license_activity_title)); if (ContentResolver.SCHEME_CONTENT.equals(uri.getScheme())) { intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); } intent.addCategory(Intent.CATEGORY_DEFAULT); intent.setPackage("com.android.htmlviewer"); try { startActivity(intent); finish(); } catch (ActivityNotFoundException e) { Log.e(TAG, "Failed to find viewer", e); showErrorAndFinish(); } } private void showErrorAndFinish() { Toast.makeText(this, R.string.settings_license_activity_unavailable, Toast.LENGTH_LONG).show(); finish(); } private boolean isFilePathValid(final String path) { return !TextUtils.isEmpty(path) && isFileValid(new File(path)); } @VisibleForTesting boolean isFileValid(final File file) { return file.exists() && file.length() != 0; } }