Android ActionBar實現下拉式導航

  利用Actionbar同樣可以很輕松的實現下拉式的導航方式，相比與tab的方式下拉式的導航方式更類型于html中的<select>標簽。若想實現這種效果：1）actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST)  2)setListNavigationCallbacks(SpinnerAdapter adapter,ActionBar.OnNavigationListener callback).

首先是創建一個Fragment類：

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>

自定義的用于顯示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;
    }

}