Java tutorial
/*- * Copyright (C) 2009 Google Inc. * * 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.google.android.demos.jamendo.app; import com.google.android.demos.jamendo.R; import com.google.android.demos.jamendo.net.QueryBuilder; import com.google.android.demos.jamendo.provider.JamendoContract; import com.google.android.demos.jamendo.provider.JamendoContract.Artists; import com.google.android.demos.jamendo.widget.ArtistGalleryAdapter; import com.google.android.demos.jamendo.widget.CompositeOnItemSelectedListener; import com.google.android.demos.jamendo.widget.GalleryDecorator; import com.google.android.demos.jamendo.widget.GalleryScrollListener; import com.google.android.demos.jamendo.widget.StatusViewManager; import com.google.android.demos.jamendo.widget.Loadable; import android.content.ContentUris; import android.content.Intent; import android.content.res.Resources; import android.database.Cursor; import android.database.DataSetObserver; import android.net.Uri; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.Window; import android.widget.AdapterView; import android.widget.Gallery; import android.widget.TextView; public class ArtistGalleryActivity extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor>, AdapterView.OnItemClickListener, View.OnClickListener { private static final int LOADER_ARTISTS = 1; private Gallery mGallery; private TextView mTextArtistName; private TextView mTextArtistGenre; private ArtistGalleryAdapter mAdapter; private Loadable mArtists; private int mImageSize; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); setContentView(R.layout.jamendo_gallery); mGallery = (Gallery) findViewById(android.R.id.list); mTextArtistName = (TextView) findViewById(R.id.text1); mTextArtistGenre = (TextView) findViewById(R.id.text2); Resources resources = getResources(); mImageSize = resources.getDimensionPixelSize(R.dimen.gallery_size); ArtistDetailsObserver artistDetailsObserver = new ArtistDetailsObserver(); mAdapter = new ArtistGalleryAdapter(this); mAdapter.registerDataSetObserver(artistDetailsObserver); mArtists = new Loadable(getSupportLoaderManager(), LOADER_ARTISTS, new StatusViewManager(this, LOADER_ARTISTS, this, this)); mGallery.setAdapter(new GalleryDecorator(mAdapter, this)); mGallery.setOnItemClickListener(this); mGallery.setOnItemSelectedListener(new CompositeOnItemSelectedListener(artistDetailsObserver, mAdapter, new GalleryScrollListener(mArtists))); mArtists.init(); } /** {@inheritDoc} */ public Loader<Cursor> onCreateLoader(int loaderId, Bundle args) { Intent intent = getIntent(); Uri uri = Artists.CONTENT_URI; String selectionExtra = intent.getStringExtra(JamendoContract.EXTRA_SELECTION); QueryBuilder builder = new QueryBuilder(selectionExtra); builder.append(JamendoContract.PARAM_IMAGE_SIZE, String.valueOf(mImageSize)); String[] projection = ArtistGalleryAdapter.PROJECTION; String selection = builder.build(); String[] selectionArgs = intent.getStringArrayExtra(JamendoContract.EXTRA_SELECTION_ARGS); String sortOrder = intent.getStringExtra(JamendoContract.EXTRA_SORT_ORDER); return new CursorLoader(this, uri, projection, selection, selectionArgs, sortOrder); } /** {@inheritDoc} */ public void onLoadFinished(Loader<Cursor> loader, Cursor data) { mAdapter.swapCursor(data); } /** {@inheritDoc} */ public void onLoaderReset(Loader<Cursor> loader) { mAdapter.swapCursor(null); } /** * {@inheritDoc} */ public void onItemClick(AdapterView<?> parent, View view, int position, long id) { if (position == parent.getSelectedItemPosition()) { Uri uri = ContentUris.withAppendedId(Artists.CONTENT_URI, id); Intent intent = new Intent(Intent.ACTION_VIEW, uri); startActivity(intent); } } private void setArtistDetails(Object item) { String artistName = mAdapter.getArtistName(item); String artistGenre = mAdapter.getArtistGenre(item); mTextArtistName.setText(artistName); mTextArtistGenre.setText(artistGenre); } private void clearArtistDetails() { mTextArtistName.setText(""); mTextArtistGenre.setText(""); } @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.list_options_menu, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.menu_refresh: mArtists.refresh(); return true; default: return super.onOptionsItemSelected(item); } } /** {@inheritDoc} */ public void onClick(View v) { switch (v.getId()) { case R.id.retry: mArtists.retry(); break; } } private final class ArtistDetailsObserver extends DataSetObserver implements AdapterView.OnItemSelectedListener { @Override public void onChanged() { Object item = mGallery.getSelectedItem(); setArtistDetails(item); } /** * {@inheritDoc} */ public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { Object item = parent.getItemAtPosition(position); setArtistDetails(item); } /** * {@inheritDoc} */ public void onNothingSelected(AdapterView<?> parent) { clearArtistDetails(); } } }