Android 抽屉效果的导航菜单实现

抽屉效果的导航菜单

　　看了很多应用，觉得这种侧滑的抽屉效果的菜单很好。

　　不用切换到另一个页面，也不用去按菜单的硬件按钮，直接在界面上一个按钮点击，菜单就滑出来，而且感觉能放很多东西。

　　关于实现，搜索了一下，有如下两种：

　　1.用SlidingDrawer：

　　http://developer.android.com/reference/android/widget/SlidingDrawer.html

　　但是不知道为什么这个类官方不建议再继续用了：

　　Deprecated since API level 17

　　2.用DrawerLayout：

　　http://developer.android.com/reference/android/support/v4/widget/DrawerLayout.html

　　Guide在这里：

　　http://developer.android.com/training/implementing-navigation/nav-drawer.html

库的引用

　　首先， DrawerLayout这个类是在Support Library里的，需要加上android-support-v4.jar这个包。

　　然后程序中用时在前面导入import android.support.v4.widget.DrawerLayout;

　　如果找不到这个类，首先用SDK Manager更新一下Android Support Library，然后在Android SDK\extras\android\support\v4路径下找到android-support-v4.jar，复制到项目的libs路径，将其Add to Build Path.

代码1

　　布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <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 -->
        <!-- main content must be the first element of DrawerLayout because it will be drawn first and drawer must be on top of it -->

        <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="left"
            android:background="#111"
            android:choiceMode="singleChoice"
            android:divider="@android:color/transparent"
            android:dividerHeight="0dp" />
    </android.support.v4.widget.DrawerLayout>

</RelativeLayout>

　　DrawerLayout的第一个子元素是主要内容，即抽屉没有打开时显示的布局。这里采用了一个FrameLayout，里面什么也没放。

　　DrawerLayout的第二个子元素是抽屉中的内容，即抽屉布局，这里采用了一个ListView。

　　主要的Activity（从官方实例中扒出来的）：

package com.example.hellodrawer;

import android.os.Bundle;
import android.app.Activity;
import android.content.res.Configuration;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;

public class HelloDrawerActivity extends Activity
{

    private String[] mPlanetTitles;
    private DrawerLayout mDrawerLayout;
    private ActionBarDrawerToggle mDrawerToggle;
    private ListView mDrawerList;

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

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

        // init the ListView and Adapter, nothing new
        initListView();

        // set a custom shadow that overlays the main content when the drawer
        // opens
        mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
                GravityCompat.START);

        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)
            {

                invalidateOptionsMenu(); // creates call to
                                            // onPrepareOptionsMenu()
            }

            /** Called when a drawer has settled in a completely open state. */
            public void onDrawerOpened(View drawerView)
            {

                invalidateOptionsMenu(); // creates call to
                                            // onPrepareOptionsMenu()
            }
        };

        // Set the drawer toggle as the DrawerListener
        mDrawerLayout.setDrawerListener(mDrawerToggle);

        // enable ActionBar app icon to behave as action to toggle nav drawer
        getActionBar().setDisplayHomeAsUpEnabled(true);
        // getActionBar().setHomeButtonEnabled(true);
        // Note: getActionBar() Added in API level 11
    }

    private void initListView()
    {
        mDrawerList = (ListView) findViewById(R.id.left_drawer);

        mPlanetTitles = getResources().getStringArray(R.array.planets_array);

        // Set the adapter for the list view
        mDrawerList.setAdapter(new ArrayAdapter<String>(this,
                R.layout.list_item, mPlanetTitles));
        // Set the list's click listener
        mDrawerList.setOnItemClickListener(new OnItemClickListener()
        {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id)
            {
                // Highlight the selected item, update the title, and close the
                // drawer
                mDrawerList.setItemChecked(position, true);
                setTitle(mPlanetTitles[position]);
                mDrawerLayout.closeDrawer(mDrawerList);
            }
        });
    }

    @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);
    }

}

　　比较纠结的是用了Level 11的一个API，这样minSdkVersion就有限制，不能太低。

　　图片资源Android官网示例处提供下载了。

　　程序运行后效果如下：

　　抽屉打开前：

　　抽屉打开后：

代码2

　　今天又看了一下DrawerLayout的类，发现有很多方法可以直接用的。

　　重新试了一下，其实不用上面那么麻烦，随便自己定义一个按钮控制抽屉的打开就行：

　　布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".DrawerActivity" >

    <android.support.v4.widget.DrawerLayout
        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" >

            <Button
                android:id="@+id/btn"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="open" 
                />
        </FrameLayout>

        <!-- The navigation drawer -->

        <ListView
            android:id="@+id/left_drawer"
            android:layout_width="240dp"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            android:background="#111"
            android:choiceMode="singleChoice"
            android:divider="@android:color/transparent"
            android:dividerHeight="0dp" />
    </android.support.v4.widget.DrawerLayout>

</RelativeLayout>

　　主要代码：

package com.example.hellodrawer;

import android.os.Bundle;
import android.app.Activity;
import android.support.v4.widget.DrawerLayout;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class DrawerActivity extends Activity
{
    private DrawerLayout mDrawerLayout = null;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drawer);

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

        Button button = (Button) findViewById(R.id.btn);
        button.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v)
            {
                // 按钮按下，将抽屉打开
                mDrawerLayout.openDrawer(Gravity.LEFT);

            }
        });
    }

}