Android ActionBar实现下拉式导航

  利用Actionbar同样可以很轻松的实现下拉式的导航方式，相比与tab的方式下拉式的导航方式更类型于html中的<select>标签。若想实现这种效果：1）actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST)  2)setListNavigationCallbacks(SpinnerAdapter adapter,ActionBar.OnNavigationListener callback).

首先是创建一个Fragment类：

package ccom.app.main;    import android.annotation.SuppressLint;  import android.app.Fragment;  import android.content.Context;  import android.os.Bundle;  import android.view.LayoutInflater;  import android.view.View;  import android.view.ViewGroup;  import android.view.ViewGroup.LayoutParams;  import android.widget.TextView;    @SuppressLint("NewApi")  public class MyFragment extends Fragment {     @Override   public View onCreateView(LayoutInflater inflater, ViewGroup container,     Bundle savedInstanceState) {      Context context = this.getActivity();      TextView tv = new TextView(context);      Bundle arc = this.getArguments();      int tabs=arc.getInt("key");        tv.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,      LayoutParams.WRAP_CONTENT));      tv.setText("hello actionbar "+tabs);      return tv;     }    }

<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"      tools:context=".Main" >        <LinearLayout          android:id="@+id/content"          android:layout_width="match_parent"          android:layout_height="match_parent"          android:orientation="vertical" />    </RelativeLayout>

自定义的用于显示textview的mytextview.xml:

<?xml version="1.0" encoding="utf-8"?>  <TextView xmlns:android="http://schemas.android.com/apk/res/android"      android:id="@+id/text1"      android:textColor="#fff"      android:background="#696969"      android:layout_width="60sp"      android:layout_height="match_parent"      android:textAppearance="?android:attr/textAppearanceListItemSmall"      android:gravity="center_vertical"      android:paddingStart="?android:attr/listPreferredItemPaddingStart"      android:minHeight="?android:attr/listPreferredItemHeightSmall"  />

package ccom.app.main;    import android.annotation.SuppressLint;  import android.app.ActionBar;  import android.app.Activity;  import android.app.FragmentTransaction;  import android.os.Bundle;  import android.widget.ArrayAdapter;    @SuppressLint("NewApi")  public class Main extends Activity implements ActionBar.OnNavigationListener {     ActionBar actionBar = null;     @Override   protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);      actionBar = this.getActionBar();      actionBar.setDisplayShowTitleEnabled(true);      actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);      actionBar.setListNavigationCallbacks(new ArrayAdapter(Main.this,      R.layout.mytextview, R.id.text1, new String[] { "tab1", "tab2",        "tab3" }), this);     }     @Override   public boolean onNavigationItemSelected(int itemPosition, long itemId) {      MyFragment mf = new MyFragment();    Bundle bundle = new Bundle();    bundle.putInt("key", itemPosition + 1);    mf.setArguments(bundle);      FragmentTransaction action = this.getFragmentManager()      .beginTransaction();    action.replace(R.id.content, mf);    action.commit();    return true;   }    }