Android开发之学习官方文档Navigation Drawer记录
Creating a Navigation Drawer
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This lesson teaches you to:
Create a Drawer Layout
Initialize the Drawer List
Handle Navigation Click Events
Listen for Open and Close Events
Open and Close with the App Icon
The navigation drawer is a panel that displays the app’s main navigation options on the left edge of the screen. It is hidden most of the time, but is revealed when the user swipes a finger from the left edge of the screen or, while at the top level of the app, the user touches the app icon in the action bar.
导航抽屉式一个显示应用程序的主要导航选项的面板，它显示在屏幕的左边。在大部分时间内它是隐藏状态的，当用户用一直手指从屏幕的左边缘滑动时，导航抽屉就会显示出来。或者在栈顶的应用程序，用户在操作栏触摸应用程序的图标时，它也会显示出来。
This lesson describes how to implement a navigation drawer using the DrawerLayout APIs available in the Support Library.
本段描述如何使用支持库中的DrawerLayout 的APIS 去实现一个导航抽屉
Navigation Drawer Design
Before you decide to use a navigation drawer in your app, you should understand the use cases and design principles defined in the Navigation Drawer design guide.
在你决定在你的应用程序中使用一个导航抽屉前，你应该了解在Navigation Drawer 设计指导中的使用案例和设计规则。
Create a Drawer Layout
创建一个抽屉布局
To add a navigation drawer, declare your user interface with aDrawerLayout object as the root view of your layout. Inside theDrawerLayout, add one view that contains the main content for the screen (your primary layout when the drawer is hidden) and another view that contains the contents of the navigation drawer.
添加一个导航抽屉，你需要将你的用户界面用一个DrawerLayout 对象作为你布局文件的根视图。DrawerLayout添加一个包含主要文本的视图，该文本视图为在屏幕中主要去显示文本内容。在抽屉隐藏时，该视图也是你的主要布局。另外一个视图包含了导航抽屉里的内容视图
For example, the following layout uses a DrawerLayout with two child views: a FrameLayout to contain the main content (populated by a Fragment at runtime), and a ListView for the navigation drawer.
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- The main content view -->
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- The navigation drawer -->
<ListView android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
This layout demonstrates some important layout characteristics:
上面的布局示范了一些重要的布局特征
The main content view (the FrameLayout above) must be the first child in the DrawerLayout because the XML order implies z-ordering and the drawer must be on top of the content.
在DrawerLayout中，主文本视图必须是第一个字视图。因为xml的执行顺序意味着Z轴和抽屉必须在文本的顶部
The main content view is set to match the parent view's width and height, because it represents the entire UI when the navigation drawer is hidden.
主文本视图的宽高设置为匹配父窗体。因为在抽屉处于隐藏状态下进入UI界面时作为主要的视图。
The drawer view (the ListView) must specify its horizontal gravity with the android:layout_gravityattribute. To support right-to-left (RTL) languages, specify the value with "start" instead of "left" (so the drawer appears on the right when the layout is RTL).
抽屉视图必须制定是水平方向的listView。制定start代替left
The drawer view specifies its width in dp units and the height matches the parent view. The drawer width should be no more than 320dp so the user can always see a portion of the main content.
抽屉视图制定的宽是按dp为代码计算高匹配父窗体。抽屉的宽应该不超过320dp一边用户可以一直看到主文本的一部分
Initialize the Drawer List
In your activity, one of the first things to do is initialize the navigation drawer's list of items. How you do so depends on the content of your app, but a navigation drawer often consists of a ListView, so the list should be populated by an Adapter (such as ArrayAdapter or SimpleCursorAdapter).
在你的activity中，第一件事情应该是初始化这个导航抽屉的列表项。如何去实现取决于你的应用程序的内容。但是一个导航抽屉通常由一个listView构成，所以如果你使用listView的话应该给它填充一个适配器
For example, here's how you can initialize the navigation list with a string array:
public class MainActivity extends Activity {
private String[] mPlanetTitles;
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
...
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mPlanetTitles = getResources().getStringArray(R.array.planets_array);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// Set the adapter for the list view
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
// Set the list's click listener
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
...
}
}
This code also calls setOnItemClickListener() to receive click events in the navigation drawer's list. The next section shows how to implement this interface and change the content view when the user selects an item.
Handle Navigation Click Events
When the user selects an item in the drawer's list, the system calls , android.view.View, int, long)">onItemClick() on theOnItemClickListener given to setOnItemClickListener().
当用户在抽屉列表中选择一个项时，系统在OnItemClickListener的onItemClick方法
What you do in the , android.view.View, int, long)">onItemClick() method depends on how you've implemented your app structure. In the following example, selecting each item in the list inserts a different Fragment into the main content view (theFrameLayout element identified by the R.id.content_frame ID):
在onItemClick方法中做什么取决于你如何实现你的应用程序结构。下面的例子演示选择每一个项都插入一个不同的Fragment到这个主要的文本视图。
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
selectItem(position);
}
}
/** Swaps fragments in the main content view */
private void selectItem(int position) {
// Create a new fragment and specify the planet to show based on position
Fragment fragment = new PlanetFragment();
Bundle args = new Bundle();
args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);
fragment.setArguments(args);
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment)
.commit();
// Highlight the selected item, update the title, and close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mPlanetTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
Listen for Open and Close Events
监听打开或者关闭事件
To listen for drawer open and close events, call setDrawerListener() on your DrawerLayout and pass it an implementation of DrawerLayout.DrawerListener. This interface provides callbacks for drawer events such asonDrawerOpened() and onDrawerClosed().
在你的DrawerLayout中调用setDrawerListener去监听抽屉的打开或者关闭事件。你可以实现DrawerLayout.DrawerListener.去达到以上操作的目的。该接口提供了抽屉事件的回调方法。
However, rather than implementing the DrawerLayout.DrawerListener, if your activity includes the action bar, you can instead extend the ActionBarDrawerToggle class. The ActionBarDrawerToggle implementsDrawerLayout.DrawerListener so you can still override those callbacks, but it also facilitates the proper interaction behavior between the action bar icon and the navigation drawer (discussed further in the next section).
然而，如果你的activity包括了action bar ,你可以集成ActionBarDrawerToggle类，而不是实现DrawerLayout.DrawerListener。ActionBarDrawerToggle实现了DrawerLayout.DrawerListener一边你仍然可以重写那些回调方法，但是这样有助于完善操作栏图标和导航抽屉的交互行为（将在下一章节讨论。
As discussed in the Navigation Drawer design guide, you should modify the contents of the action bar when the drawer is visible, such as to change the title and remove action items that are contextual to the main content. The following code shows how you can do so by overriding DrawerLayout.DrawerListener callback methods with an instance of the ActionBarDrawerToggle class:
正如导航抽屉设置指南中所讨论的，在抽屉是可见状态时，你应该修改action bar的内容，例如改变主要文本上下文的标题或者移除操作项。以下代码向你展示如何在ActionBarDrawerToggle的实例对象中去覆盖DrawerLayout.DrawerListener回调方法
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
...
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
mTitle = mDrawerTitle = getTitle();
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, R.string.drawer_open, R.string.drawer_close) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
// Set the drawer toggle as the DrawerListener
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
}
The next section describes the ActionBarDrawerToggle constructor arguments and the other steps required to set it up to handle interaction with the action bar icon.
下面章节讨论ActionBarDrawerToggle的构造参数和其他的在创建和操作action bar 图标时的要求的步骤
Open and Close with the App Icon
Users can open and close the navigation drawer with a swipe gesture from or towards the left edge of the screen, but if you're using the action bar, you should also allow users to open and close it by touching the app icon. And the app icon should also indicate the presence of the navigation drawer with a special icon. You can implement all this behavior by using the ActionBarDrawerToggle shown in the previous section.
用户可以从屏幕的左边缘用一个滑动操作打开或者关闭导航抽屉，但如果你使用action bar，你应该允许用户通过触摸应用程序图标打开和关闭导航抽屉。应用突变也应该用一个指定的图标指明导航抽屉。你通过可以使用ActionBarDrawerToggle是实现所有的行为
To make ActionBarDrawerToggle work, create an instance of it with its constructor, which requires the following arguments:
The Activity hosting the drawer.
The DrawerLayout.
A drawable resource to use as the drawer indicator.
The standard navigation drawer icon is available in the Download the Action Bar Icon Pack.
A String resource to describe the "open drawer" action (for accessibility).
A String resource to describe the "close drawer" action (for accessibility).
Then, whether or not you've created a subclass of ActionBarDrawerToggle as your drawer listener, you need to call upon your ActionBarDrawerToggle in a few places throughout your activity lifecycle:
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mDrawerToggle;
...
public void onCreate(Bundle savedInstanceState) {
...
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer icon to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description */
R.string.drawer_close /* "close drawer" description */
) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
getActionBar().setTitle(mTitle);
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
getActionBar().setTitle(mDrawerTitle);
}
};
// Set the drawer toggle as the DrawerListener
mDrawerLayout.setDrawerListener(mDrawerToggle);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Pass the event to ActionBarDrawerToggle, if it returns
// true, then it has handled the app icon touch event
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle your other action bar items...
return super.onOptionsItemSelected(item);
}
...
}