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Android example source code file (LauncherActivity.java)

This example Android source code file (LauncherActivity.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

activityadapter, android, arraylist, canvas, content, drawing, filterresults, graphics, iconresizer, intent, layoutinflater, listitem, object, override, paint, paintdrawable, resolveinfo, string, ui, view

The LauncherActivity.java Android example source code

/*
 * 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 android.app;

import android.content.Context;
import android.content.Intent;
import android.content.pm.ComponentInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.PaintDrawable;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


/**
 * Displays a list of all activities which can be performed
 * for a given intent. Launches when clicked.
 *
 */
public abstract class LauncherActivity extends ListActivity {
    Intent mIntent;
    PackageManager mPackageManager;
    IconResizer mIconResizer;
    
    /**
     * An item in the list
     */
    public static class ListItem {
        public ResolveInfo resolveInfo;
        public CharSequence label;
        public Drawable icon;
        public String packageName;
        public String className;
        public Bundle extras;
        
        ListItem(PackageManager pm, ResolveInfo resolveInfo, IconResizer resizer) {
            this.resolveInfo = resolveInfo;
            label = resolveInfo.loadLabel(pm);
            ComponentInfo ci = resolveInfo.activityInfo;
            if (ci == null) ci = resolveInfo.serviceInfo;
            if (label == null && ci != null) {
                label = resolveInfo.activityInfo.name;
            }
            
            if (resizer != null) {
                icon = resizer.createIconThumbnail(resolveInfo.loadIcon(pm));
            }
            packageName = ci.applicationInfo.packageName;
            className = ci.name;
        }

        public ListItem() {
        }
    }

    /**
     * Adapter which shows the set of activities that can be performed for a given intent.
     */
    private class ActivityAdapter extends BaseAdapter implements Filterable {
        private final Object lock = new Object();
        private ArrayList<ListItem> mOriginalValues;

        protected final IconResizer mIconResizer;
        protected final LayoutInflater mInflater;

        protected List<ListItem> mActivitiesList;

        private Filter mFilter;
        
        public ActivityAdapter(IconResizer resizer) {
            mIconResizer = resizer;
            mInflater = (LayoutInflater) LauncherActivity.this.getSystemService(
                    Context.LAYOUT_INFLATER_SERVICE);
            mActivitiesList = makeListItems();
        }

        public Intent intentForPosition(int position) {
            if (mActivitiesList == null) {
                return null;
            }

            Intent intent = new Intent(mIntent);
            ListItem item = mActivitiesList.get(position);
            intent.setClassName(item.packageName, item.className);
            if (item.extras != null) {
                intent.putExtras(item.extras);
            }
            return intent;
        }

        public ListItem itemForPosition(int position) {
            if (mActivitiesList == null) {
                return null;
            }

            return mActivitiesList.get(position);
        }

        public int getCount() {
            return mActivitiesList != null ? mActivitiesList.size() : 0;
        }

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

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

        public View getView(int position, View convertView, ViewGroup parent) {
            View view;
            if (convertView == null) {
                view = mInflater.inflate(
                        com.android.internal.R.layout.activity_list_item_2, parent, false);
            } else {
                view = convertView;
            }
            bindView(view, mActivitiesList.get(position));
            return view;
        }

        private void bindView(View view, ListItem item) {
            TextView text = (TextView) view;
            text.setText(item.label);
            if (item.icon == null) {
                item.icon = mIconResizer.createIconThumbnail(
                        item.resolveInfo.loadIcon(getPackageManager()));
            }
            text.setCompoundDrawablesWithIntrinsicBounds(item.icon, null, null, null);
        }
        
        public Filter getFilter() {
            if (mFilter == null) {
                mFilter = new ArrayFilter();
            }
            return mFilter;
        }
        
        /**
         * An array filters constrains the content of the array adapter with a prefix. Each
         * item that does not start with the supplied prefix is removed from the list.
         */
        private class ArrayFilter extends Filter {
            @Override
            protected FilterResults performFiltering(CharSequence prefix) {
                FilterResults results = new FilterResults();

                if (mOriginalValues == null) {
                    synchronized (lock) {
                        mOriginalValues = new ArrayList<ListItem>(mActivitiesList);
                    }
                }

                if (prefix == null || prefix.length() == 0) {
                    synchronized (lock) {
                        ArrayList<ListItem> list = new ArrayList(mOriginalValues);
                        results.values = list;
                        results.count = list.size();
                    }
                } else {
                    final String prefixString = prefix.toString().toLowerCase();

                    ArrayList<ListItem> values = mOriginalValues;
                    int count = values.size();

                    ArrayList<ListItem> newValues = new ArrayList(count);

                    for (int i = 0; i < count; i++) {
                        ListItem item = values.get(i);

                        String[] words = item.label.toString().toLowerCase().split(" ");
                        int wordCount = words.length;

                        for (int k = 0; k < wordCount; k++) {
                            final String word = words[k];

                            if (word.startsWith(prefixString)) {
                                newValues.add(item);
                                break;
                            }
                        }
                    }

                    results.values = newValues;
                    results.count = newValues.size();
                }

                return results;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                //noinspection unchecked
                mActivitiesList = (List<ListItem>) results.values;
                if (results.count > 0) {
                    notifyDataSetChanged();
                } else {
                    notifyDataSetInvalidated();
                }
            }
        }
    }
        
    /**
     * Utility class to resize icons to match default icon size.  
     */
    public class IconResizer {
        // Code is borrowed from com.android.launcher.Utilities. 
        private int mIconWidth = -1;
        private int mIconHeight = -1;

        private final Rect mOldBounds = new Rect();
        private Canvas mCanvas = new Canvas();
        
        public IconResizer() {
            mCanvas.setDrawFilter(new PaintFlagsDrawFilter(Paint.DITHER_FLAG,
                    Paint.FILTER_BITMAP_FLAG));
            
            final Resources resources = LauncherActivity.this.getResources();
            mIconWidth = mIconHeight = (int) resources.getDimension(
                    android.R.dimen.app_icon_size);
        }

        /**
         * Returns a Drawable representing the thumbnail of the specified Drawable.
         * The size of the thumbnail is defined by the dimension
         * android.R.dimen.launcher_application_icon_size.
         *
         * This method is not thread-safe and should be invoked on the UI thread only.
         *
         * @param icon The icon to get a thumbnail of.
         *
         * @return A thumbnail for the specified icon or the icon itself if the
         *         thumbnail could not be created. 
         */
        public Drawable createIconThumbnail(Drawable icon) {
            int width = mIconWidth;
            int height = mIconHeight;

            final int iconWidth = icon.getIntrinsicWidth();
            final int iconHeight = icon.getIntrinsicHeight();

            if (icon instanceof PaintDrawable) {
                PaintDrawable painter = (PaintDrawable) icon;
                painter.setIntrinsicWidth(width);
                painter.setIntrinsicHeight(height);
            }

            if (width > 0 && height > 0) {
                if (width < iconWidth || height < iconHeight) {
                    final float ratio = (float) iconWidth / iconHeight;

                    if (iconWidth > iconHeight) {
                        height = (int) (width / ratio);
                    } else if (iconHeight > iconWidth) {
                        width = (int) (height * ratio);
                    }

                    final Bitmap.Config c = icon.getOpacity() != PixelFormat.OPAQUE ?
                                Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
                    final Bitmap thumb = Bitmap.createBitmap(mIconWidth, mIconHeight, c);
                    final Canvas canvas = mCanvas;
                    canvas.setBitmap(thumb);
                    // Copy the old bounds to restore them later
                    // If we were to do oldBounds = icon.getBounds(),
                    // the call to setBounds() that follows would
                    // change the same instance and we would lose the
                    // old bounds
                    mOldBounds.set(icon.getBounds());
                    final int x = (mIconWidth - width) / 2;
                    final int y = (mIconHeight - height) / 2;
                    icon.setBounds(x, y, x + width, y + height);
                    icon.draw(canvas);
                    icon.setBounds(mOldBounds);
                    icon = new BitmapDrawable(getResources(), thumb);
                } else if (iconWidth < width && iconHeight < height) {
                    final Bitmap.Config c = Bitmap.Config.ARGB_8888;
                    final Bitmap thumb = Bitmap.createBitmap(mIconWidth, mIconHeight, c);
                    final Canvas canvas = mCanvas;
                    canvas.setBitmap(thumb);
                    mOldBounds.set(icon.getBounds());
                    final int x = (width - iconWidth) / 2;
                    final int y = (height - iconHeight) / 2;
                    icon.setBounds(x, y, x + iconWidth, y + iconHeight);
                    icon.draw(canvas);
                    icon.setBounds(mOldBounds);
                    icon = new BitmapDrawable(getResources(), thumb);
                }
            }

            return icon;
        }
    }

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        
        mPackageManager = getPackageManager();
    
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setProgressBarIndeterminateVisibility(true);
        onSetContentView();
            
        mIconResizer = new IconResizer();
        
        mIntent = new Intent(getTargetIntent());
        mIntent.setComponent(null);
        mAdapter = new ActivityAdapter(mIconResizer);
        
        setListAdapter(mAdapter);
        getListView().setTextFilterEnabled(true);
        
        setProgressBarIndeterminateVisibility(false);
    }

    /**
     * Override to call setContentView() with your own content view to
     * customize the list layout.
     */
    protected void onSetContentView() {
        setContentView(com.android.internal.R.layout.activity_list);
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        Intent intent = intentForPosition(position);
        startActivity(intent);
    }
    
    /**
     * Return the actual Intent for a specific position in our
     * {@link android.widget.ListView}.
     * @param position The item whose Intent to return
     */
    protected Intent intentForPosition(int position) {
        ActivityAdapter adapter = (ActivityAdapter) mAdapter;
        return adapter.intentForPosition(position);
    }
    
    /**
     * Return the {@link ListItem} for a specific position in our
     * {@link android.widget.ListView}.
     * @param position The item to return
     */
    protected ListItem itemForPosition(int position) {
        ActivityAdapter adapter = (ActivityAdapter) mAdapter;
        return adapter.itemForPosition(position);
    }
    
    /**
     * Get the base intent to use when running
     * {@link PackageManager#queryIntentActivities(Intent, int)}.
     */
    protected Intent getTargetIntent() {
        return new Intent();
    }

    /**
     * Perform query on package manager for list items.  The default
     * implementation queries for activities.
     */
    protected List<ResolveInfo> onQueryPackageManager(Intent queryIntent) {
        return mPackageManager.queryIntentActivities(queryIntent, /* no flags */ 0);
    }
    
    /**
     * Perform the query to determine which results to show and return a list of them.
     */
    public List<ListItem> makeListItems() {
        // Load all matching activities and sort correctly
        List<ResolveInfo> list = onQueryPackageManager(mIntent);
        Collections.sort(list, new ResolveInfo.DisplayNameComparator(mPackageManager));
        
        ArrayList<ListItem> result = new ArrayList(list.size());
        int listSize = list.size();
        for (int i = 0; i < listSize; i++) {
            ResolveInfo resolveInfo = list.get(i);
            result.add(new ListItem(mPackageManager, resolveInfo, null));
        }

        return result;
    }
}

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