AndroidLabor4HomeScreen

ApplicationInfo.java

class ApplicationInfo {
    /**
     * The application name.
     */
    CharSequence title;

    /**
     * The intent used to start the application.
     */
    Intent intent;

    /**
     * The application icon.
     */
    Drawable icon;

    /**
     * When set to true, indicates that the icon has been resized.
     */
    boolean filtered;

    /**
     * Creates the application intent based on a component name and various launch flags.
     *
     * @param className the class name of the component representing the intent
     * @param launchFlags the launch flags
     */
    final void setActivity(ComponentName className, int launchFlags) {
        intent = new Intent(Intent.ACTION_MAIN);
        intent.addCategory(Intent.CATEGORY_LAUNCHER);
        intent.setComponent(className);
        intent.setFlags(launchFlags);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (!(o instanceof ApplicationInfo)) {
            return false;
        }

        ApplicationInfo that = (ApplicationInfo) o;
        return title.equals(that.title) &&
                intent.getComponent().getClassName().equals(
                        that.intent.getComponent().getClassName());
    }

    @Override
    public int hashCode() {
        int result;
        result = (title != null ? title.hashCode() : 0);
        final String name = intent.getComponent().getClassName();
        result = 31 * result + (name != null ? name.hashCode() : 0);
        return result;
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<!-- All applications on the top side of the screen -->
    <GridView 
    	android:id="@+id/all_apps"
        android:persistentDrawingCache="animation|scrolling"
        android:alwaysDrawnWithCache="true"
        android:scrollbars="none"
        android:drawSelectorOnTop="false"
        android:numColumns="auto_fit"
        android:columnWidth="78dp"
        android:stretchMode="spacingWidth"
        android:layout_weight="1.0"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:stackFromBottom="true"
        android:visibility="visible" />
</LinearLayout>

MainActivity.java [loadApplications() metódus]

private void loadApplications(){
    	// PackageManager referencia
    	PackageManager manager = getPackageManager();
    	
    	// listat keszitunk az osszes megjelenitendo alkalmazasrol
        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        final List<ResolveInfo> apps = manager.queryIntentActivities(mainIntent, 0);
        // rendezzuk nev szerint
        Collections.sort(apps, new ResolveInfo.DisplayNameComparator(manager));
        
        // feltoltjuk az ApplicationInfo tombot minden megjelenitendo alkalamzashoz
        if (apps != null) {
            final int count = apps.size();

            if (mApplications == null) {
                mApplications = new ArrayList<ApplicationInfo>(count);
            }
            mApplications.clear();

            for (int i = 0; i < count; i++) {
                ApplicationInfo application = new ApplicationInfo();
                ResolveInfo info = apps.get(i);
                
                // alkalmazas neve
                application.title = info.loadLabel(manager);
                // ahhoz hogy kattintasra el tudjuk inditani, kelleni fog egy megfelelo Activity-re mutato Intent
                application.setActivity(new ComponentName(
                        info.activityInfo.applicationInfo.packageName,
                        info.activityInfo.name),
                        Intent.FLAG_ACTIVITY_NEW_TASK
                        | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
                // ikon
                application.icon = info.activityInfo.loadIcon(manager);

                mApplications.add(application);
            }
        }
    }   

MainActivity.java [saját grid adapter]

/**
 * Egyedi grid adatper az ApplicationInfo tombhoz
 */
private class ApplicationsAdapter extends ArrayAdapter<ApplicationInfo> {
    private Rect mOldBounds = new Rect();

    public ApplicationsAdapter(Context context, ArrayList<ApplicationInfo> apps) {
        super(context, 0, apps);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final ApplicationInfo info = mApplications.get(position);
        
        // ez egy trukk a meglevo convertView objektum ujrahasznositasahoz
        // sokat javit a sebessegen, erdemes hasznalni!
        if (convertView == null) {
            final LayoutInflater inflater = getLayoutInflater();
            convertView = inflater.inflate(R.layout.application, parent, false);
        }

        Drawable icon = info.icon;

        if (!info.filtered) {
            final Resources resources = getContext().getResources();
            int width = (int) resources.getDimension(android.R.dimen.app_icon_size);
            int height = (int) resources.getDimension(android.R.dimen.app_icon_size);

            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 && (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(width, height, c);
                final Canvas canvas = new Canvas(thumb);
                canvas.setDrawFilter(new PaintFlagsDrawFilter(Paint.DITHER_FLAG, 0));
                // 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());
                icon.setBounds(0, 0, width, height);
                icon.draw(canvas);
                icon.setBounds(mOldBounds);
                icon = info.icon = new BitmapDrawable(thumb);
                info.filtered = true;
            }
        }

        final TextView textView = (TextView) convertView.findViewById(R.id.label);
        textView.setCompoundDrawablesWithIntrinsicBounds(null, icon, null, null);
        textView.setText(info.title);

        return convertView;
    }
}