A list view that demonstrates the use of setEmptyView. This example alos uses a custom layout file that adds some extra buttons to the screen. : Button « UI « Android

1. Android
2. UI
3. Button

A list view that demonstrates the use of setEmptyView. This example alos uses a custom layout file that adds some extra buttons to the screen.

 
 
 
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.view;

import com.example.android.apis.R;

import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.AbsListView;

import java.util.ArrayList;


/**
 * A list view that demonstrates the use of setEmptyView. This example alos uses
 * a custom layout file that adds some extra buttons to the screen.
 */
public class List8 extends ListActivity {

    PhotoAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Use a custom layout file
        setContentView(R.layout.list_8);
        
        // Tell the list view which view to display when the list is empty
        getListView().setEmptyView(findViewById(R.id.empty));
        
        // Set up our adapter
        mAdapter = new PhotoAdapter(this);
        setListAdapter(mAdapter);
        
        // Wire up the clear button to remove all photos
        Button clear = (Button) findViewById(R.id.clear);
        clear.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                mAdapter.clearPhotos();
            } });
        
        // Wire up the add button to add a new photo
        Button add = (Button) findViewById(R.id.add);
        add.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                mAdapter.addPhotos();
            } });
    }

    /**
     * A simple adapter which maintains an ArrayList of photo resource Ids. 
     * Each photo is displayed as an image. This adapter supports clearing the
     * list of photos and adding a new photo.
     *
     */
    public class PhotoAdapter extends BaseAdapter {

        private Integer[] mPhotoPool = {
                R.drawable.sample_thumb_0, R.drawable.sample_thumb_1, R.drawable.sample_thumb_2,
                R.drawable.sample_thumb_3, R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
                R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};

        private ArrayList<Integer> mPhotos = new ArrayList<Integer>();
        
        public PhotoAdapter(Context c) {
            mContext = c;
        }

        public int getCount() {
            return mPhotos.size();
        }

        public Object getItem(int position) {
            return position;
        }

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

        public View getView(int position, View convertView, ViewGroup parent) {
            // Make an ImageView to show a photo
            ImageView i = new ImageView(mContext);

            i.setImageResource(mPhotos.get(position));
            i.setAdjustViewBounds(true);
            i.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.WRAP_CONTENT,
                    LayoutParams.WRAP_CONTENT));
            // Give it a nice background
            i.setBackgroundResource(R.drawable.picture_frame);
            return i;
        }

        private Context mContext;

        public void clearPhotos() {
            mPhotos.clear();
            notifyDataSetChanged();
        }
        
        public void addPhotos() {
            int whichPhoto = (int)Math.round(Math.random() * (mPhotoPool.length - 1));
            int newPhoto = mPhotoPool[whichPhoto];
            mPhotos.add(newPhoto);
            notifyDataSetChanged();
        }

    }
}
//list_8.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2007 The Android Open Source Project

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
  
          http://www.apache.org/licenses/LICENSE-2.0
  
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent" 
    android:layout_height="match_parent">
    
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent" 
        android:layout_height="wrap_content">
        
        <Button android:id="@+id/add"
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content"
            android:text="@string/list_8_new_photo"/>
            
        <Button android:id="@+id/clear"
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content"
            android:text="@string/list_8_clear_photos"/>
            
    </LinearLayout>
    
    <!-- The frame layout is here since we will be showing either
    the empty view or the list view.  -->
    <FrameLayout
        android:layout_width="match_parent" 
        android:layout_height="0dip"
        android:layout_weight="1" >
        <!-- Here is the list. Since we are using a ListActivity, we
             have to call it "@android:id/list" so ListActivity will
             find it -->
        <ListView android:id="@android:id/list"
            android:layout_width="match_parent" 
            android:layout_height="match_parent"
            android:drawSelectorOnTop="false"/>
        
        <!-- Here is the view to show if the list is emtpy -->
        <TextView android:id="@+id/empty"
            android:layout_width="match_parent" 
            android:layout_height="match_parent"
            android:text="list_8_no_photos"/>
            
    </FrameLayout>
        
</LinearLayout>

   
  

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