samples/training/multiscreen/newsreader/src/com/example/android/newsreader/NewsReaderActivity.java - platform/development - Git at Google

 /*
  * Copyright (C) 2011 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.example.android.newsreader;

 import android.app.AlertDialog;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.v4.app.FragmentActivity;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.SpinnerAdapter;

 /**
  * Main activity: shows headlines list and articles, if layout permits.
  *
  * This is the main activity of the application. It can have several different layouts depending
  * on the SDK version, screen size and orientation. The configurations are divided in two large
  * groups: single-pane layouts and dual-pane layouts.
  *
  * In single-pane mode, this activity shows a list of headlines using a {@link HeadlinesFragment}.
  * When the user clicks on a headline, a separate activity (a {@link ArticleActivity}) is launched
  * to show the news article.
  *
  * In dual-pane mode, this activity shows a {@HeadlinesFragment} on the left side and an
  * {@ArticleFragment} on the right side. When the user selects a headline on the left, the
  * corresponding article is shown on the right.
  *
  * If an Action Bar is available (large enough screen and SDK version 11 or up), navigation
  * controls are shown in the Action Bar (whether to show tabs or a list depends on the layout).
  * If an Action Bar is not available, a regular image and button are shown in the top area of
  * the screen, emulating an Action Bar.
  */
 public class NewsReaderActivity extends FragmentActivity
         implements HeadlinesFragment.OnHeadlineSelectedListener,
                    CompatActionBarNavListener,
                    OnClickListener  {

     // Whether or not we are in dual-pane mode
     boolean mIsDualPane = false;

     // The fragment where the headlines are displayed
     HeadlinesFragment mHeadlinesFragment;

     // The fragment where the article is displayed (null if absent)
     ArticleFragment mArticleFragment;

     // The news category and article index currently being displayed
     int mCatIndex = 0;
     int mArtIndex = 0;
     NewsCategory mCurrentCat;

     // List of category titles
     final String CATEGORIES[] = { "Top Stories", "Politics", "Economy", "Technology" };

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main_layout);

         // find our fragments
         mHeadlinesFragment = (HeadlinesFragment) getSupportFragmentManager().findFragmentById(
                 R.id.headlines);
         mArticleFragment = (ArticleFragment) getSupportFragmentManager().findFragmentById(
                 R.id.article);

         // Determine whether we are in single-pane or dual-pane mode by testing the visibility
         // of the article view.
         View articleView = findViewById(R.id.article);
         mIsDualPane = articleView != null && articleView.getVisibility() == View.VISIBLE;

         // Register ourselves as the listener for the headlines fragment events.
         mHeadlinesFragment.setOnHeadlineSelectedListener(this);

         // Set up the Action Bar (or not, if one is not available)
         int catIndex = savedInstanceState == null ? 0 : savedInstanceState.getInt("catIndex", 0);
         setUpActionBar(mIsDualPane, catIndex);

         // Set up headlines fragment
         mHeadlinesFragment.setSelectable(mIsDualPane);
         restoreSelection(savedInstanceState);

         // Set up the category button (shown if an Action Bar is not available)
         Button catButton = (Button) findViewById(R.id.categorybutton);
         if (catButton != null) {
             catButton.setOnClickListener(this);
         }
     }

     /** Restore category/article selection from saved state. */
     void restoreSelection(Bundle savedInstanceState) {
         if (savedInstanceState != null) {
             setNewsCategory(savedInstanceState.getInt("catIndex", 0));
             if (mIsDualPane) {
                 int artIndex = savedInstanceState.getInt("artIndex", 0);
                 mHeadlinesFragment.setSelection(artIndex);
                 onHeadlineSelected(artIndex);
             }
         }
     }

     @Override
     public void onRestoreInstanceState(Bundle savedInstanceState) {
         restoreSelection(savedInstanceState);
     }

     /** Sets up Action Bar (if present).
      *
      * @param showTabs whether to show tabs (if false, will show list).
      * @param selTab the selected tab or list item.
      */
     public void setUpActionBar(boolean showTabs, int selTab) {
         if (Build.VERSION.SDK_INT < 11) {
             // No action bar for you!
             // But do not despair. In this case the layout includes a bar across the
             // top that looks and feels like an action bar, but is made up of regular views.
             return;
         }

         android.app.ActionBar actionBar = getActionBar();
         actionBar.setDisplayShowTitleEnabled(false);

         // Set up a CompatActionBarNavHandler to deliver us the Action Bar nagivation events
         CompatActionBarNavHandler handler = new CompatActionBarNavHandler(this);
         if (showTabs) {
             actionBar.setNavigationMode(android.app.ActionBar.NAVIGATION_MODE_TABS);
             int i;
             for (i = 0; i < CATEGORIES.length; i++) {
                 actionBar.addTab(actionBar.newTab().setText(CATEGORIES[i]).setTabListener(handler));
             }
             actionBar.setSelectedNavigationItem(selTab);
         }
         else {
             actionBar.setNavigationMode(android.app.ActionBar.NAVIGATION_MODE_LIST);
             SpinnerAdapter adap = new ArrayAdapter<String>(this, R.layout.actionbar_list_item,
                     CATEGORIES);
             actionBar.setListNavigationCallbacks(adap, handler);
         }

         // Show logo instead of icon+title.
         actionBar.setDisplayUseLogoEnabled(true);
     }

     @Override
     public void onStart() {
         super.onStart();
         setNewsCategory(0);
     }

     /** Sets the displayed news category.
      *
      * This causes the headlines fragment to be repopulated with the appropriate headlines.
      */
     void setNewsCategory(int categoryIndex) {
         mCatIndex = categoryIndex;
         mCurrentCat = NewsSource.getInstance().getCategory(categoryIndex);
         mHeadlinesFragment.loadCategory(categoryIndex);

         // If we are displaying the article on the right, we have to update that too
         if (mIsDualPane) {
             mArticleFragment.displayArticle(mCurrentCat.getArticle(0));
         }

         // If we are displaying a "category" button (on the ActionBar-less UI), we have to update
         // its text to reflect the current category.
         Button catButton = (Button) findViewById(R.id.categorybutton);
         if (catButton != null) {
             catButton.setText(CATEGORIES[mCatIndex]);
         }
     }

     /** Called when a headline is selected.
      *
      * This is called by the HeadlinesFragment (via its listener interface) to notify us that a
      * headline was selected in the Action Bar. The way we react depends on whether we are in
      * single or dual-pane mode. In single-pane mode, we launch a new activity to display the
      * selected article; in dual-pane mode we simply display it on the article fragment.
      *
      * @param index the index of the selected headline.
      */
     @Override
     public void onHeadlineSelected(int index) {
         mArtIndex = index;
         if (mIsDualPane) {
             // display it on the article fragment
             mArticleFragment.displayArticle(mCurrentCat.getArticle(index));
         }
         else {
             // use separate activity
             Intent i = new Intent(this, ArticleActivity.class);
             i.putExtra("catIndex", mCatIndex);
             i.putExtra("artIndex", index);
             startActivity(i);
         }
     }

     /** Called when a news category is selected.
      *
      * This is called by our CompatActionBarNavHandler in response to the user selecting a
      * news category in the Action Bar. We react by loading and displaying the headlines for
      * that category.
      *
      * @param catIndex the index of the selected news category.
      */
     @Override
     public void onCategorySelected(int catIndex) {
         setNewsCategory(catIndex);
     }

     /** Save instance state. Saves current category/article index. */
     @Override
     protected void onSaveInstanceState(Bundle outState) {
         outState.putInt("catIndex", mCatIndex);
         outState.putInt("artIndex", mArtIndex);
         super.onSaveInstanceState(outState);
     }

     /** Called when news category button is clicked.
      *
      * This is the button that we display on UIs that don't have an action bar. This button
      * calls up a list of news categories and switches to the given category.
      */
     @Override
     public void onClick(View v) {
         AlertDialog.Builder builder = new AlertDialog.Builder(this);
         builder.setTitle("Select a Category");
         builder.setItems(CATEGORIES, new DialogInterface.OnClickListener() {
             @Override
             public void onClick(DialogInterface dialog, int which) {
                 setNewsCategory(which);
             }
         });
         AlertDialog d = builder.create();
         d.show();
     }
 }
	/*
	* Copyright (C) 2011 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.example.android.newsreader;

	import android.app.AlertDialog;
	import android.content.DialogInterface;
	import android.content.Intent;
	import android.os.Build;
	import android.os.Bundle;
	import android.support.v4.app.FragmentActivity;
	import android.view.View;
	import android.view.View.OnClickListener;
	import android.widget.ArrayAdapter;
	import android.widget.Button;
	import android.widget.SpinnerAdapter;

	/**
	* Main activity: shows headlines list and articles, if layout permits.
	*
	* This is the main activity of the application. It can have several different layouts depending
	* on the SDK version, screen size and orientation. The configurations are divided in two large
	* groups: single-pane layouts and dual-pane layouts.
	*
	* In single-pane mode, this activity shows a list of headlines using a {@link HeadlinesFragment}.
	* When the user clicks on a headline, a separate activity (a {@link ArticleActivity}) is launched
	* to show the news article.
	*
	* In dual-pane mode, this activity shows a {@HeadlinesFragment} on the left side and an
	* {@ArticleFragment} on the right side. When the user selects a headline on the left, the
	* corresponding article is shown on the right.
	*
	* If an Action Bar is available (large enough screen and SDK version 11 or up), navigation
	* controls are shown in the Action Bar (whether to show tabs or a list depends on the layout).
	* If an Action Bar is not available, a regular image and button are shown in the top area of
	* the screen, emulating an Action Bar.
	*/
	public class NewsReaderActivity extends FragmentActivity
	implements HeadlinesFragment.OnHeadlineSelectedListener,
	CompatActionBarNavListener,
	OnClickListener {

	// Whether or not we are in dual-pane mode
	boolean mIsDualPane = false;

	// The fragment where the headlines are displayed
	HeadlinesFragment mHeadlinesFragment;

	// The fragment where the article is displayed (null if absent)
	ArticleFragment mArticleFragment;

	// The news category and article index currently being displayed
	int mCatIndex = 0;
	int mArtIndex = 0;
	NewsCategory mCurrentCat;

	// List of category titles
	final String CATEGORIES[] = { "Top Stories", "Politics", "Economy", "Technology" };

	@Override
	public void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.main_layout);

	// find our fragments
	mHeadlinesFragment = (HeadlinesFragment) getSupportFragmentManager().findFragmentById(
	R.id.headlines);
	mArticleFragment = (ArticleFragment) getSupportFragmentManager().findFragmentById(
	R.id.article);

	// Determine whether we are in single-pane or dual-pane mode by testing the visibility
	// of the article view.
	View articleView = findViewById(R.id.article);
	mIsDualPane = articleView != null && articleView.getVisibility() == View.VISIBLE;

	// Register ourselves as the listener for the headlines fragment events.
	mHeadlinesFragment.setOnHeadlineSelectedListener(this);

	// Set up the Action Bar (or not, if one is not available)
	int catIndex = savedInstanceState == null ? 0 : savedInstanceState.getInt("catIndex", 0);
	setUpActionBar(mIsDualPane, catIndex);

	// Set up headlines fragment
	mHeadlinesFragment.setSelectable(mIsDualPane);
	restoreSelection(savedInstanceState);

	// Set up the category button (shown if an Action Bar is not available)
	Button catButton = (Button) findViewById(R.id.categorybutton);
	if (catButton != null) {
	catButton.setOnClickListener(this);
	}
	}

	/** Restore category/article selection from saved state. */
	void restoreSelection(Bundle savedInstanceState) {
	if (savedInstanceState != null) {
	setNewsCategory(savedInstanceState.getInt("catIndex", 0));
	if (mIsDualPane) {
	int artIndex = savedInstanceState.getInt("artIndex", 0);
	mHeadlinesFragment.setSelection(artIndex);
	onHeadlineSelected(artIndex);
	}
	}
	}

	@Override
	public void onRestoreInstanceState(Bundle savedInstanceState) {
	restoreSelection(savedInstanceState);
	}

	/** Sets up Action Bar (if present).
	*
	* @param showTabs whether to show tabs (if false, will show list).
	* @param selTab the selected tab or list item.
	*/
	public void setUpActionBar(boolean showTabs, int selTab) {
	if (Build.VERSION.SDK_INT < 11) {
	// No action bar for you!
	// But do not despair. In this case the layout includes a bar across the
	// top that looks and feels like an action bar, but is made up of regular views.
	return;
	}

	android.app.ActionBar actionBar = getActionBar();
	actionBar.setDisplayShowTitleEnabled(false);

	// Set up a CompatActionBarNavHandler to deliver us the Action Bar nagivation events
	CompatActionBarNavHandler handler = new CompatActionBarNavHandler(this);
	if (showTabs) {
	actionBar.setNavigationMode(android.app.ActionBar.NAVIGATION_MODE_TABS);
	int i;
	for (i = 0; i < CATEGORIES.length; i++) {
	actionBar.addTab(actionBar.newTab().setText(CATEGORIES[i]).setTabListener(handler));
	}
	actionBar.setSelectedNavigationItem(selTab);
	}
	else {
	actionBar.setNavigationMode(android.app.ActionBar.NAVIGATION_MODE_LIST);
	SpinnerAdapter adap = new ArrayAdapter<String>(this, R.layout.actionbar_list_item,
	CATEGORIES);
	actionBar.setListNavigationCallbacks(adap, handler);
	}

	// Show logo instead of icon+title.
	actionBar.setDisplayUseLogoEnabled(true);
	}

	@Override
	public void onStart() {
	super.onStart();
	setNewsCategory(0);
	}

	/** Sets the displayed news category.
	*
	* This causes the headlines fragment to be repopulated with the appropriate headlines.
	*/
	void setNewsCategory(int categoryIndex) {
	mCatIndex = categoryIndex;
	mCurrentCat = NewsSource.getInstance().getCategory(categoryIndex);
	mHeadlinesFragment.loadCategory(categoryIndex);

	// If we are displaying the article on the right, we have to update that too
	if (mIsDualPane) {
	mArticleFragment.displayArticle(mCurrentCat.getArticle(0));
	}

	// If we are displaying a "category" button (on the ActionBar-less UI), we have to update
	// its text to reflect the current category.
	Button catButton = (Button) findViewById(R.id.categorybutton);
	if (catButton != null) {
	catButton.setText(CATEGORIES[mCatIndex]);
	}
	}

	/** Called when a headline is selected.
	*
	* This is called by the HeadlinesFragment (via its listener interface) to notify us that a
	* headline was selected in the Action Bar. The way we react depends on whether we are in
	* single or dual-pane mode. In single-pane mode, we launch a new activity to display the
	* selected article; in dual-pane mode we simply display it on the article fragment.
	*
	* @param index the index of the selected headline.
	*/
	@Override
	public void onHeadlineSelected(int index) {
	mArtIndex = index;
	if (mIsDualPane) {
	// display it on the article fragment
	mArticleFragment.displayArticle(mCurrentCat.getArticle(index));
	}
	else {
	// use separate activity
	Intent i = new Intent(this, ArticleActivity.class);
	i.putExtra("catIndex", mCatIndex);
	i.putExtra("artIndex", index);
	startActivity(i);
	}
	}

	/** Called when a news category is selected.
	*
	* This is called by our CompatActionBarNavHandler in response to the user selecting a
	* news category in the Action Bar. We react by loading and displaying the headlines for
	* that category.
	*
	* @param catIndex the index of the selected news category.
	*/
	@Override
	public void onCategorySelected(int catIndex) {
	setNewsCategory(catIndex);
	}

	/** Save instance state. Saves current category/article index. */
	@Override
	protected void onSaveInstanceState(Bundle outState) {
	outState.putInt("catIndex", mCatIndex);
	outState.putInt("artIndex", mArtIndex);
	super.onSaveInstanceState(outState);
	}

	/** Called when news category button is clicked.
	*
	* This is the button that we display on UIs that don't have an action bar. This button
	* calls up a list of news categories and switches to the given category.
	*/
	@Override
	public void onClick(View v) {
	AlertDialog.Builder builder = new AlertDialog.Builder(this);
	builder.setTitle("Select a Category");
	builder.setItems(CATEGORIES, new DialogInterface.OnClickListener() {
	@Override
	public void onClick(DialogInterface dialog, int which) {
	setNewsCategory(which);
	}
	});
	AlertDialog d = builder.create();
	d.show();
	}
	}