Question

我想在操作栏上单击按钮时显示包含数组列表中项目的Drop down。

有没有好的练习/教程来实现这个目标？

Answer 1

我认为你可以将arraylist作为微调数据库

Spinner mySpinner = (Spinner) findViewById(R.id.my_spinner);
//adapter helps to add data to spinner.
ArrayAdapter<String> adapter = new ArrayAdapter<String>      (MainActivity.this,android.R.layout.simple_spinner_dropdown_item,user_spinner_string);
mySpinner.setAdapter(adapter);

Answer 2

SpinnerNavItem.java

public class SpinnerNavItem {

    private String title;
    private int icon;

    public SpinnerNavItem(String title, int icon){
        this.title = title;
        this.icon = icon;
    }

    public String getTitle(){
        return this.title;      
    }

    public int getIcon(){
        return this.icon;
    }
}

list_item_title_navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="fill_parent"
    android:padding="5dp" >

    <ImageView android:id="@+id/imgIcon"
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_launcher"
        android:layout_marginRight="5dp"
        />

    <TextView android:id="@+id/txtTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@id/imgIcon"/>

</RelativeLayout>

TitleNavigationAdapter.java

public class TitleNavigationAdapter extends BaseAdapter {

    private ImageView imgIcon;
    private TextView txtTitle;
    private ArrayList<SpinnerNavItem> spinnerNavItem;
    private Context context;

    public TitleNavigationAdapter(Context context,
            ArrayList<SpinnerNavItem> spinnerNavItem) {
        this.spinnerNavItem = spinnerNavItem;
        this.context = context;
    }

    @Override
    public int getCount() {
        return spinnerNavItem.size();
    }

    @Override
    public Object getItem(int index) {
        return spinnerNavItem.get(index);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) { 
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.list_item_title_navigation, null);
        }

        imgIcon = (ImageView) convertView.findViewById(R.id.imgIcon);
        txtTitle = (TextView) convertView.findViewById(R.id.txtTitle);

        imgIcon.setImageResource(spinnerNavItem.get(position).getIcon());
        imgIcon.setVisibility(View.GONE);
        txtTitle.setText(spinnerNavItem.get(position).getTitle());
        return convertView;
    }


    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.list_item_title_navigation, null);
        }

        imgIcon = (ImageView) convertView.findViewById(R.id.imgIcon);
        txtTitle = (TextView) convertView.findViewById(R.id.txtTitle);

        imgIcon.setImageResource(spinnerNavItem.get(position).getIcon());        
        txtTitle.setText(spinnerNavItem.get(position).getTitle());
        return convertView;
    }

}

MainActivity.java

public class MainActivity extends Activity implements ActionBar.OnNavigationListener{

    // action bar
    private ActionBar actionBar;

    // Title navigation Spinner data
    private ArrayList<SpinnerNavItem> navSpinner;

    // Navigation adapter
    private TitleNavigationAdapter adapter;

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

        actionBar = getActionBar();

        // Hide the action bar title
        actionBar.setDisplayShowTitleEnabled(false);

        // Enabling Spinner dropdown navigation
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

        // Spinner title navigation data
        navSpinner = new ArrayList<SpinnerNavItem>();
        navSpinner.add(new SpinnerNavItem("Local", R.drawable.ic_location));
        navSpinner.add(new SpinnerNavItem("My Places", R.drawable.ic_my_places));
        navSpinner.add(new SpinnerNavItem("Checkins", R.drawable.ic_checkin));
        navSpinner.add(new SpinnerNavItem("Latitude", R.drawable.ic_latitude));     

        // title drop down adapter
        adapter = new TitleNavigationAdapter(getApplicationContext(), navSpinner);

        // assigning the spinner navigation     
        actionBar.setListNavigationCallbacks(adapter, this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    ....
    }

    /**
     * On selecting action bar icons
     * */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
    ...
    }

    /**
     * Actionbar navigation item select listener
     * */
    @Override
    public boolean onNavigationItemSelected(int itemPosition, long itemId) {
    // Action to be taken after selecting a spinner item
        return false;
    }
}

设置操作栏按钮的下拉列表

2 个答案: