ThemeUtils.java

package org.openintents.shopping.theme;

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.Resources;
import android.content.res.XmlResourceParser;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Xml;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;

import org.openintents.shopping.ShoppingApplication;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

/**
 * Helper functions for retrieving remote themes, that are themes in external
 * packages.
 *
 * @author Peli
 */
public class ThemeUtils {
    private static final String TAG = "ThemeUtils";

    public static final String METADATA_THEMES = "org.openintents.themes";

    // For XML:

    public static String SCHEMA = "http://schemas.openintents.org/android/themes";

    public static final String ELEM_THEMES = "themes";
    public static final String ELEM_ATTRIBUTESET = "attributeset";
    public static final String ELEM_THEME = "theme";

    public static final String ATTR_NAME = "name";
    public static final String ATTR_TITLE = "title";
    public static final String ATTR_STYLE = "style";

    public static int[] getAttributeIds(Context context, String[] attrNames,
                                        String packageName) {
        int len = attrNames.length;
        Resources res = context.getResources();

        int[] attrIds = new int[len];
        for (int i = 0; i < len; i++) {
            attrIds[i] = res.getIdentifier(attrNames[i], "attr", packageName);
        }
        return attrIds;
    }

    /**
     * Return list of all applications that contain the theme meta-tag.
     *
     * @param pm
     * @param firstPackage : package name of package that should be moved to front.
     * @return
     */
    private static List<ApplicationInfo> getThemePackages(PackageManager pm,
                                                          String firstPackage) {
        List<ApplicationInfo> appinfolist = new LinkedList<>();

        try {
            List<ApplicationInfo> allapps = pm
                    .getInstalledApplications(PackageManager.GET_META_DATA);
            for (ApplicationInfo ai : allapps) {
                if (ai.metaData != null) {
                    if (ai.metaData.containsKey(METADATA_THEMES)) {
                        if (ai.packageName.equals(firstPackage)) {
                            // Add this package at the beginning of the list
                            appinfolist.add(0, ai);
                        } else {
                            appinfolist.add(ai);
                        }
                    }
                }
            }
            return appinfolist;
        } catch (Exception e) {
            // getInstalledApplications can throw android.os.TransactionTooLargeException (data > 1mb)
        }

        return appinfolist;
    }

    private static void addThemeInfos(PackageManager pm, String attributeset,
                                      ApplicationInfo appinfo, List<ThemeInfo> themeinfolist) {
        XmlResourceParser xml = appinfo.loadXmlMetaData(pm, METADATA_THEMES);

        boolean useThisAttributeSet = false;

        try {
            int tagType = xml.next();
            while (XmlPullParser.END_DOCUMENT != tagType) {

                if (XmlPullParser.START_TAG == tagType) {

                    AttributeSet attr = Xml.asAttributeSet(xml);

                    if (xml.getName().equals(ELEM_THEMES)) {

                    } else if (xml.getName().equals(ELEM_ATTRIBUTESET)) {
                        String name = attr.getAttributeValue(SCHEMA, ATTR_NAME);
                        useThisAttributeSet = name.equals(attributeset);
                    } else if (xml.getName().equals(ELEM_THEME)) {
                        if (useThisAttributeSet) {
                            ThemeInfo ti = new ThemeInfo();

                            ti.packageName = appinfo.packageName;
                            int titleResId = attr.getAttributeResourceValue(
                                    SCHEMA, ATTR_TITLE, 0);
                            int styleResId = attr.getAttributeResourceValue(
                                    SCHEMA, ATTR_STYLE, 0);

                            try {
                                Resources res = pm
                                        .getResourcesForApplication(appinfo);
                                ti.title = res.getString(titleResId);
                                ti.styleName = res.getResourceName(styleResId);
                            } catch (NameNotFoundException e) {
                                ti.title = "";
                            }
                            themeinfolist.add(ti);
                        }
                    }
                } else if (XmlPullParser.END_TAG == tagType) {

                }

                tagType = xml.next();
            }

        } catch (XmlPullParserException ex) {
            Log.e(TAG, String.format(
                    "XML parse exception when parsing metadata for '%s': %s",
                    appinfo.packageName, ex.getMessage()));
        } catch (IOException ex) {
            Log.e(TAG, String.format(
                    "I/O exception when parsing metadata for '%s': %s",
                    appinfo.packageName, ex.getMessage()));
        }

        xml.close();
    }

    /**
     * Create a list of all possible themes installed on the device for a
     * specific attributeset.
     *
     * @param context
     * @param attributeset
     * @return
     */
    public static List<ThemeInfo> getThemeInfos(Context context,
                                                String attributeset) {
        PackageManager pm = context.getPackageManager();
        String thisPackageName = context.getPackageName();

        List<ApplicationInfo> appinfolist = getThemePackages(pm,
                thisPackageName);
        List<ThemeInfo> themeinfolist = new LinkedList<>();

        for (ApplicationInfo ai : appinfolist) {
            addThemeInfos(pm, attributeset, ai, themeinfolist);
        }

        return themeinfolist;
    }

    public static class ThemeInfo {
        public String packageName;
        public String title;
        public String styleName;
    }

    public static String getPackageNameFromStyle(String style) {
        int pos = style.indexOf(':');
        if (pos >= 0) {
            return style.substring(0, pos);
        } else {
            return null;
        }
    }
}