1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.app; 18 19 import org.xmlpull.v1.XmlPullParser; 20 import org.xmlpull.v1.XmlPullParserException; 21 22 import android.content.Intent; 23 import android.content.pm.ActivityInfo; 24 import android.content.pm.PackageManager; 25 import android.content.res.XmlResourceParser; 26 import android.os.Bundle; 27 import android.util.AttributeSet; 28 import android.util.Xml; 29 30 import com.android.internal.util.XmlUtils; 31 32 import java.io.IOException; 33 34 /** 35 * Stub activity that launches another activity (and then finishes itself) 36 * based on information in its component's manifest meta-data. This is a 37 * simple way to implement an alias-like mechanism. 38 * 39 * To use this activity, you should include in the manifest for the associated 40 * component an entry named "android.app.alias". It is a reference to an XML 41 * resource describing an intent that launches the real application. 42 */ 43 public class AliasActivity extends Activity { 44 /** 45 * This is the name under which you should store in your component the 46 * meta-data information about the alias. It is a reference to an XML 47 * resource describing an intent that launches the real application. 48 * {@hide} 49 */ 50 public final String ALIAS_META_DATA = "android.app.alias"; 51 52 @Override onCreate(Bundle savedInstanceState)53 protected void onCreate(Bundle savedInstanceState) { 54 super.onCreate(savedInstanceState); 55 56 XmlResourceParser parser = null; 57 try { 58 ActivityInfo ai = getPackageManager().getActivityInfo( 59 getComponentName(), PackageManager.GET_META_DATA); 60 parser = ai.loadXmlMetaData(getPackageManager(), 61 ALIAS_META_DATA); 62 if (parser == null) { 63 throw new RuntimeException("Alias requires a meta-data field " 64 + ALIAS_META_DATA); 65 } 66 67 Intent intent = parseAlias(parser); 68 if (intent == null) { 69 throw new RuntimeException( 70 "No <intent> tag found in alias description"); 71 } 72 73 startActivity(intent); 74 finish(); 75 76 } catch (PackageManager.NameNotFoundException e) { 77 throw new RuntimeException("Error parsing alias", e); 78 } catch (XmlPullParserException e) { 79 throw new RuntimeException("Error parsing alias", e); 80 } catch (IOException e) { 81 throw new RuntimeException("Error parsing alias", e); 82 } finally { 83 if (parser != null) parser.close(); 84 } 85 } 86 parseAlias(XmlPullParser parser)87 private Intent parseAlias(XmlPullParser parser) 88 throws XmlPullParserException, IOException { 89 AttributeSet attrs = Xml.asAttributeSet(parser); 90 91 Intent intent = null; 92 93 int type; 94 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT 95 && type != XmlPullParser.START_TAG) { 96 } 97 98 String nodeName = parser.getName(); 99 if (!"alias".equals(nodeName)) { 100 throw new RuntimeException( 101 "Alias meta-data must start with <alias> tag; found" 102 + nodeName + " at " + parser.getPositionDescription()); 103 } 104 105 int outerDepth = parser.getDepth(); 106 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT 107 && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) { 108 if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) { 109 continue; 110 } 111 112 nodeName = parser.getName(); 113 if ("intent".equals(nodeName)) { 114 Intent gotIntent = Intent.parseIntent(getResources(), parser, attrs); 115 if (intent == null) intent = gotIntent; 116 } else { 117 XmlUtils.skipCurrentTag(parser); 118 } 119 } 120 121 return intent; 122 } 123 124 } 125