源代码解说ActionBar的各种使用方法

2022-07-22 14:36:09

1. Navigation Drawer

很多应用程序都使用了Navigation Drawer，如网易邮箱client。该控件位于 android.support.v4.widget.DrawerLayout ，使用方法例如以下，点击下载源代码：

<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 -->

     <!-- should not be larger than 320 to show content -->

    <ListView android:id="@+id/left_drawer"

        android:layout_width="180dp"

        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>

在编写代码之前确保增加了support v4库。

创建一个布局文件 fragment_layout来被一个Fragment显示

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="match_parent"

        android:text="Placeholder Text"

        android:layout_gravity="center"

        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

创建OpertingSystemFragment类

package com.vogella.android.actionbar.navigationdrawer;

import android.app.Fragment;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

public class OpertingSystemFragment extends Fragment {

  public static final String ARG_OS= "OS";

  private String string;

  @Override

  public View onCreateView(LayoutInflater inflater, ViewGroup container,

      Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_layout, null);

    TextView textView = (TextView) view.findViewById(R.id.textView1);

    textView.setText(string);

    return view;

  }

  @Override

  public void onActivityCreated(Bundle savedInstanceState) {

    super.onActivityCreated(savedInstanceState);

  }

  @Override

  public void setArguments(Bundle args) {

    string = args.getString(ARG_OS);

  }

}

加入String

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <string name="app_name">Navigationdrawer</string>

    <string name="action_settings">Settings</string>

    <string name="action_update">Update</string>

    <string name="drawer_open">Open Drawer</string>

    <string name="drawer_close">Close Drawer</string>

    <string name="hello_world">Hello world!</string>

    <string-array name="operating_systems">

        <item >Android</item>

        <item >iPhone</item>

        <item >Windows Mobile</item>

    </string-array>

</resources>

最后，创建Activity

package com.vogella.android.actionbar.navigationdrawer;

import android.app.Activity;

import android.app.Fragment;

import android.app.FragmentManager;

import android.content.res.Configuration;

import android.os.Bundle;

import android.support.v4.app.ActionBarDrawerToggle;

import android.support.v4.widget.DrawerLayout;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.AdapterView;

import android.widget.ArrayAdapter;

import android.widget.ListView;

import android.widget.Toast;

public class MainActivity extends Activity {

    private String[] mPlanetTitles;

    private DrawerLayout mDrawerLayout;

    private ListView mDrawerList;

  private ActionBarDrawerToggle mDrawerToggle;

  private CharSequence title;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        title = getActionBar().getTitle();

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

        System.out.println(mPlanetTitles.length);

        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_item,R.id.content, mPlanetTitles));

        // Set the list's click listener

        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

        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) {

                getActionBar().setTitle(title);

            }

/** Called when a drawer has settled in a completely open state. */

            public void onDrawerOpened(View drawerView) {

                getActionBar().setTitle("Open Drawer");

            }

        };

        // Set the drawer toggle as the DrawerListener

        mDrawerLayout.setDrawerListener(mDrawerToggle);

        getActionBar().setDisplayHomeAsUpEnabled(true);

        getActionBar().setHomeButtonEnabled(true);

    }

    private class DrawerItemClickListener implements ListView.OnItemClickListener {

        @Override

        public void onItemClick(AdapterView parent, View view, int position, long id) {

            selectItem(position);

        }

    }

    @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 onCreateOptionsMenu(Menu menu) {

      getMenuInflater().inflate(R.menu.main, menu);

      return super.onCreateOptionsMenu(menu);

    }

    @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...

        switch (item.getItemId()) {

    case R.id.action_settings:

      Toast.makeText(this, "Settings selected", Toast.LENGTH_LONG).show();

      break;

    default:

      break;

    }

        return super.onOptionsItemSelected(item);

    }

/** 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 OpertingSystemFragment();

        Bundle args = new Bundle();

        args.putInt(OpertingSystemFragment.ARG_OS, 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);

        getActionBar().setTitle((mPlanetTitles[position]));

        mDrawerLayout.closeDrawer(mDrawerList);

    }

}

2. ActionBar + Tab navigation + Fragment

Fragment能够用来和action bar一起使用来实现导航。以下的代码将介绍使用方法，点击下载源代码。

ackage com.vogella.android.actionbar.tabs;

import android.app.ActionBar;

import android.app.Fragment;

import android.app.FragmentTransaction;

import android.os.Bundle;

import android.support.v4.app.FragmentActivity;

import android.view.Gravity;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

public class MainActivity extends FragmentActivity implements

    ActionBar.TabListener {

/** * The serialization (saved instance state) Bundle key representing the * current tab position. */

  private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";

  @Override

  protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    // Set up the action bar to show tabs.

    final ActionBar actionBar = getActionBar();

    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // for each of the sections in the app, add a tab to the action bar.

    actionBar.addTab(actionBar.newTab().setText(R.string.title_section1)

        .setTabListener(this));

    actionBar.addTab(actionBar.newTab().setText(R.string.title_section2)

        .setTabListener(this));

    actionBar.addTab(actionBar.newTab().setText(R.string.title_section3)

        .setTabListener(this));

  }

  @Override

  public void onRestoreInstanceState(Bundle savedInstanceState) {

    // Restore the previously serialized current tab position.

    if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM)) {

      getActionBar().setSelectedNavigationItem(savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));

    }

  }

  @Override

  public void onSaveInstanceState(Bundle outState) {

    // Serialize the current tab position.

    outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getActionBar()

        .getSelectedNavigationIndex());

  }

  @Override

  public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.activity_main, menu);

    return true;

  }

  @Override

  public void onTabSelected(ActionBar.Tab tab,

      FragmentTransaction fragmentTransaction) {

    // When the given tab is selected, show the tab contents in the

    // container view.

    Fragment fragment = new DummySectionFragment();

    Bundle args = new Bundle();

    args.putInt(DummySectionFragment.ARG_SECTION_NUMBER,

        tab.getPosition() + 1);

    fragment.setArguments(args);

    getFragmentManager().beginTransaction()

        .replace(R.id.container, fragment).commit();

  }

  @Override

  public void onTabUnselected(ActionBar.Tab tab,

      FragmentTransaction fragmentTransaction) {

  }

  @Override

  public void onTabReselected(ActionBar.Tab tab,

      FragmentTransaction fragmentTransaction) {

  }

/** * A dummy fragment representing a section of the app */

  public static class DummySectionFragment extends Fragment {

    public static final String ARG_SECTION_NUMBER = "placeholder_text";

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

        Bundle savedInstanceState) {

      TextView textView = new TextView(getActivity());

      textView.setGravity(Gravity.CENTER);

      textView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));

      return textView;

    }

  }

}

3.Dropdown menu 导航

Dropdown菜单也常被用在ActionBar中，以下的代码介绍了使用方法，完整代码点击下载：

package com.vogella.android.actionbar.spinner;

import android.app.ActionBar;

import android.app.Fragment;

import android.os.Bundle;

import android.support.v4.app.FragmentActivity;

import android.view.Gravity;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.TextView;

public class MainActivity extends FragmentActivity implements

    ActionBar.OnNavigationListener {

/** * The serialization (saved instance state) Bundle key representing the * current dropdown position. */

  private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";

  @Override

  protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    // Set up the action bar to show a dropdown list.

    final ActionBar actionBar = getActionBar();

    actionBar.setDisplayShowTitleEnabled(false);

    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

    final String[] dropdownValues = getResources().getStringArray(R.array.dropdown);

    // Specify a SpinnerAdapter to populate the dropdown list.

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(actionBar.getThemedContext(),

        android.R.layout.simple_spinner_item, android.R.id.text1,

        dropdownValues);

    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    // Set up the dropdown list navigation in the action bar.

    actionBar.setListNavigationCallbacks(adapter, this);

    // use getActionBar().getThemedContext() to ensure

    // that the text color is always appropriate for the action bar

    // background rather than the activity background.

  }

  @Override

  public void onRestoreInstanceState(Bundle savedInstanceState) {

    // Restore the previously serialized current dropdown position.

    if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM)) {

      getActionBar().setSelectedNavigationItem(savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));

    }

  }

  @Override

  public void onSaveInstanceState(Bundle outState) {

    // Serialize the current dropdown position.

    outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getActionBar()

        .getSelectedNavigationIndex());

  }

  @Override

  public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.activity_main, menu);

    return true;

  }

  @Override

  public boolean onNavigationItemSelected(int position, long id) {

    // When the given dropdown item is selected, show its contents in the

    // container view.

    Fragment fragment = new DummySectionFragment();

    Bundle args = new Bundle();

    args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);

    fragment.setArguments(args);

    getFragmentManager().beginTransaction()

        .replace(R.id.container, fragment).commit();

    return true;

  }

/** * A dummy fragment */

  public static class DummySectionFragment extends Fragment {

    public static final String ARG_SECTION_NUMBER = "placeholder_text";

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

        Bundle savedInstanceState) {

      TextView textView = new TextView(getActivity());

      textView.setGravity(Gravity.CENTER);

      textView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));

      return textView;

    }

  }

}

截图例如以下：

4. 使用Contextual action 模式

Contextual action mode能够用来在程序执行时切换ActionBar的布局，以下将介绍怎样使用，完整源代码点击下载：

创建布局文件 main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <EditText

        android:id="@+id/myView"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:ems="10" >

        <requestFocus />

    </EditText>

</LinearLayout>

创建一个menu XML资源文件 contetual.xml

<?xml version="1.0" encoding="utf-8"?>

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item

        android:id="@+id/toast"

        android:title="Toast">

    </item>

</menu>

Activity中的带代码例如以下：

package de.vogella.android.socialapp;

import android.app.Activity;

import android.os.Bundle;

import android.view.ActionMode;

import android.view.Menu;

import android.view.MenuInflater;

import android.view.MenuItem;

import android.widget.Toast;

public class OverviewActivity extends Activity {

  protected Object mActionMode;

  @Override

  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    // define the contextual action mode

    View view = findViewById(R.id.myView);

    view.setOnLongClickListener(new View.OnLongClickListener() {

      // called when the user long-clicks on someView

      public boolean onLongClick(View view) {

        if (mActionMode != null) {

          return false;

        }

        // start the CAB using the ActionMode.Callback defined above

        mActionMode = OverviewActivity.this

            .startActionMode(mActionModeCallback);

        view.setSelected(true);

        return true;

      }

    });

  }

  @Override

  public boolean onCreateOptionsMenu(Menu menu) {

    MenuInflater inflater = getMenuInflater();

    inflater.inflate(R.menu.mainmenu, menu);

    return true;

  }

  @Override

  public boolean onOptionsItemSelected(MenuItem item) {

    Toast.makeText(this, "Just a test", Toast.LENGTH_SHORT).show();

    return true;

  }

  private ActionMode.Callback mActionModeCallback = new ActionMode.Callback() {

    // Called when the action mode is created; startActionMode() was called

    public boolean onCreateActionMode(ActionMode mode, Menu menu) {

      // inflate a menu resource providing context menu items

      MenuInflater inflater = mode.getMenuInflater();

      // assumes that you have "contexual.xml" menu resources

      inflater.inflate(R.menu.contextual, menu);

      return true;

    }

    // called each time the action mode is shown. Always called after

    // onCreateActionMode, but

    // may be called multiple times if the mode is invalidated.

    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {

      return false; // Return false if nothing is done

    }

    // called when the user selects a contextual menu item

    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {

      switch (item.getItemId()) {

      case R.id.toast:

        Toast.makeText(OverviewActivity.this, "Selected menu",

            Toast.LENGTH_LONG).show();

        mode.finish(); // Action picked, so close the CAB

        return true;

      default:

        return false;

      }

    }

    // called when the user exits the action mode

    public void onDestroyActionMode(ActionMode mode) {

      mActionMode = null;

    }

  };

}

本文參考了这篇文章：

Using the Android action bar (ActionBar) - Tutorial

这篇blog对ActionBar也进行了具体的介绍：

Android ActionBar全然解析，使用官方推荐的最佳导航栏(上)

当然，Android Developer也介绍的非常好：http://developer.android.com/guide/topics/ui/actionbar.html

码农公寓

Using the Android action bar (ActionBar) - Tutorial

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