Best Practices for Interaction and Engagement 官方开发手册 -Android&Java 技术笔记集册

Designing Effective Navigation

Planning Screens and Their Relationships
- 实体关系图（Entity-relationship diagram），数据、用户之间的关系、操作
- 详尽的用例场景
- 界面关系图
Planning for Multiple Touchscreen Sizes
- 界面组合技术，在平板电脑、电视上，屏幕很大，可以把列表界面和详情界面左右排布一起显示
Providing Descendant and Lateral Navigation
- Descendant，父界面前往子界面
- Lateral，兄弟界面之间的跳转
- list和section
Providing Ancestral and Temporal Navigation
- Temporal（时间性），按下返回键，应该回到上一界面
- Ancestral（父子性），ActionBar/ToolBar上的返回按钮，返回父界面（通常是上一界面，但并不全是，容纳WebView的Activity就是很好的例子），需要注意的是，一定要清除backstack
...

Implementing Effective Navigation

Creating Swipe Views with Tabs
- ViewPager，PagerTitleStrip，FragmentPagerAdapter，FragmentStatePagerAdapter
Creating a Navigation Drawer
- drawer layout里面可以显式一个菜单列表
- ActionBarDrawerToggle（appcompat-v7中）可以监听drawer的开启与关闭事件，也可以用代码控制drawer的开启与关闭
- 完整样例

Providing Up Navigation

首先在manifest里面为activity声明其parent activity，用于up navigation
然后在onOptionsItemSelected回调中处理up navigation：

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
      switch (item.getItemId()) {
      // Respond to the action bar's Up/Home button
      case android.R.id.home:
          Intent upIntent = NavUtils.getParentActivityIntent(this);
          if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
              // This activity is NOT part of this app's task, so create a new task
              // when navigating up, with a synthesized back stack.
              TaskStackBuilder.create(this)
                      // Add all of this activity's parents to the back stack
                      .addNextIntentWithParentStack(upIntent)
                      // Navigate up to the closest parent
                      .startActivities();
          } else {
              // This activity is part of this app's task, so simply
              // navigate up to the logical parent activity.
              NavUtils.navigateUpTo(this, upIntent);
          }
          return true;
      }
      return super.onOptionsItemSelected(item);
  }

Providing Proper Back Navigation

安卓系统都有一个物理返回键，所以不应该在UI上额外添加一个返回键
安卓系统的back stack通常情况下都可以应对back navigation

但是以下情况需要特殊考虑

从通知栏消息、widget、navigation drawer直接进入一个深层次的activity

    // Intent for the activity to open when user selects the notification
    Intent detailsIntent = new Intent(this, DetailsActivity.class);

    // Use TaskStackBuilder to build the back stack and get the PendingIntent
    PendingIntent pendingIntent =
            TaskStackBuilder.create(this)
                            // add all of DetailsActivity's parents to the stack,
                            // followed by DetailsActivity itself
                            .addNextIntentWithParentStack(upIntent)
                            .getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

    NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
    builder.setContentIntent(pendingIntent);

fragment之间的导航

    // Works with either the framework FragmentManager or the
    // support package FragmentManager (getSupportFragmentManager).
    getSupportFragmentManager().beginTransaction()
                            .add(detailFragment, "detail")
                            // Add this transaction to the back stack
                            .addToBackStack()
                            .commit();

需要注意的是，当fragment是在ViewPager中水平切换时，不应该把transaction 加入到 backstack中。

WebView

    @Override
    public void onBackPressed() {
        if (mWebView.canGoBack()) {
            mWebView.goBack();
            return;
        }

        // Otherwise defer to system default behavior.
        super.onBackPressed();
    }

Implementing Descendant Navigation
- 通常都是Intent加上startActivity(intent)，或者FragmentTransaction来完成向子界面的导航
- 需要注意的是，如果app将打开其他app的界面，为了防止用户中途离开，再次从launcher打开app时，却是其他app的界面，可以为intent设置FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET flag
```
  Intent externalActivityIntent = new Intent(Intent.ACTION_PICK);
  externalActivityIntent.setType("image/*");
  externalActivityIntent.addFlags(
          Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
  startActivity(externalActivityIntent);
```

Notifying the User

Building a Notification
- 使用NotificationCompat.Builder创建通知栏消息
- 响应用户对通知栏消息的点击，启动相应Activity，同时要考虑是否提供返回的导航设计
Preserving Navigation when Starting an Activity
- 点击通知栏消息，可能会启动两种类型的Activity：正常使用流程会启动的Activity；仅仅是把通知栏消息展开的Activity；
- 前者通常需要提供back导航支持，在manifest中声明Activity父子关系，同时构造PendingIntent时构造back stack，使用stackBuilder.getPendingIntent创建PendingIntent
- 后者通常不需要加入到back stack中，无需手动构造back stack，使用PendingIntent.getActivity创建PendingIntent，同时在manifest中设置以下选项：
```
  <activity
      android:name=".ResultActivity"
  ...
      android:launchMode="singleTask"
      android:taskAffinity=""
      android:excludeFromRecents="true">
  </activity>
```

完整示例：

Intent resultIntent = new Intent(this, ResultActivity.class);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
// Adds the back stack
stackBuilder.addParentStack(ResultActivity.class);
// Adds the Intent to the top of the stack
stackBuilder.addNextIntent(resultIntent);
// Gets a PendingIntent containing the entire back stack
PendingIntent resultPendingIntent =
        stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this)
    .setSmallIcon(R.drawable.notification_icon)
    .setContentTitle("My notification")
    .setContentText("Hello World!")
    .setContentIntent(resultPendingIntent);

// Sets an ID for the notification
int mNotificationId = 001;
// Gets an instance of the NotificationManager service
NotificationManager mNotifyMgr = 
        (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// Builds the notification and issues it.
mNotifyMgr.notify(mNotificationId, mBuilder.build());

Updating Notifications
- 创建通知栏消息时，如果指定了id，以后可以通过id对已经显示的消息进行修改/更新、移除操作；
- 修改/更新只需以相同的id，新的Notification对象，调用mNotifyMgr.notify即可；
- 如果消息支持被移除，则用户可以手动移除（单个或者所有），setAutoCancel()会让消息在用户点击时自动消失；cancel(id)和cancelAll()可以代码移除通知栏消息；

Using Big View Styles

Android 4.1之后，通知栏消息引入了action的支持，方便用户快捷操作

// Sets up the Snooze and Dismiss action buttons that will appear in the
// big view of the notification.
Intent dismissIntent = new Intent(this, PingService.class);
dismissIntent.setAction(CommonConstants.ACTION_DISMISS);
PendingIntent piDismiss = PendingIntent.getService(this, 0, dismissIntent, 0);

Intent snoozeIntent = new Intent(this, PingService.class);
snoozeIntent.setAction(CommonConstants.ACTION_SNOOZE);
PendingIntent piSnooze = PendingIntent.getService(this, 0, snoozeIntent, 0);

// Constructs the Builder object.
NotificationCompat.Builder builder =
        new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.ic_stat_notification)
        .setContentTitle(getString(R.string.notification))
        .setContentText(getString(R.string.ping))
        .setDefaults(Notification.DEFAULT_ALL) // requires VIBRATE permission
        /*
        * Sets the big view "big text" style and supplies the
        * text (the user's reminder message) that will be displayed
        * in the detail area of the expanded notification.
        * These calls are ignored by the support library for
        * pre-4.1 devices.
        */
        .setStyle(new NotificationCompat.BigTextStyle()
                .bigText(msg))
        .addAction (R.drawable.ic_stat_dismiss,
                getString(R.string.dismiss), piDismiss)
        .addAction (R.drawable.ic_stat_snooze,
                getString(R.string.snooze), piSnooze);

Displaying Progress in a Notification
- setProgress (int max, int progress, boolean indeterminate)可以为通知栏消息设置进度条，支持实时进度、持续模式

Supporting Swipe-to-Refresh
- 官方有SwipeRefreshLayout
- 民间有Ultra Pull To Refresh
- 滑到底部触发加载更多可以使用Mugen

Adding Search Functionality

在App Bar中添加SearchView，注意它有support版本

res/menu/options_menu.xml：

    <?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:android="http://schemas.android.com/apk/res/android">
        <item android:id="@+id/search"
            android:title="@string/search_title"
            android:icon="@drawable/ic_search"
            android:showAsAction="collapseActionView|ifRoom"
            android:actionViewClass="android.widget.SearchView" />
    </menu>

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.options_menu, menu);

        return true;
    }

创建可搜索的配置

res/xml/searchable.xml，配置SearchView的label，hint

    <?xml version="1.0" encoding="utf-8"?>
    <searchable xmlns:android="http://schemas.android.com/apk/res/android"
            android:label="@string/app_name"
            android:hint="@string/search_hint" />

manifest

    <activity ... >
        ...
        <meta-data android:name="android.app.searchable"
                android:resource="@xml/searchable" />

    </activity>

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.options_menu, menu);

        // Associate searchable configuration with the SearchView
        SearchManager searchManager =
            (SearchManager) getSystemService(Context.SEARCH_SERVICE);
        SearchView searchView =
                (SearchView) menu.findItem(R.id.search).getActionView();
        searchView.setSearchableInfo(
                searchManager.getSearchableInfo(getComponentName()));

        return true;
    }

当用户提交一个query时，SearchView会发出一个ACTION_SEARCH intent，需要在manifest文件中声明响应此intent

Making Your App Content Searchable by Google
- Google对如何优化对app内的内容、网站的搜索，提供了相应的建议
- Deep Links，通过在manifest中声明感兴趣的Intent，可以在用户在其他app内触发此intent时启动自己的app，intent可以设置action, category, scheme来进行过滤
优化app的assistant内容
app link，让自己的app成为自己网站uri的默认打开方式

Best Practices for Interaction and Engagement

在这篇文章中：

Designing Effective Navigation

Implementing Effective Navigation

目录