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 import com.android.internal.util.XmlUtils; 30 31 import java.io.IOException; 32 33 /** 34 * Stub activity that launches another activity (and then finishes itself) 35 * based on information in its component's manifest meta-data. This is a 36 * simple way to implement an alias-like mechanism. 37 * 38 * To use this activity, you should include in the manifest for the associated 39 * component an entry named "android.app.alias". It is a reference to an XML 40 * resource describing an intent that launches the real application. 41 */ 42 public class AliasActivity extends Activity { 43 /** 44 * This is the name under which you should store in your component the 45 * meta-data information about the alias. It is a reference to an XML 46 * resource describing an intent that launches the real application. 47 * {@hide} 48 */ 49 public final String ALIAS_META_DATA = "android.app.alias"; 50 51 @Override onCreate(Bundle savedInstanceState)52 protected void onCreate(Bundle savedInstanceState) { 53 super.onCreate(savedInstanceState); 54 55 XmlResourceParser parser = null; 56 try { 57 ActivityInfo ai = getPackageManager().getActivityInfo( 58 getComponentName(), PackageManager.GET_META_DATA); 59 parser = ai.loadXmlMetaData(getPackageManager(), 60 ALIAS_META_DATA); 61 if (parser == null) { 62 throw new RuntimeException("Alias requires a meta-data field " 63 + ALIAS_META_DATA); 64 } 65 66 Intent intent = parseAlias(parser); 67 if (intent == null) { 68 throw new RuntimeException( 69 "No <intent> tag found in alias description"); 70 } 71 72 startActivity(intent); 73 finish(); 74 75 } catch (PackageManager.NameNotFoundException e) { 76 throw new RuntimeException("Error parsing alias", e); 77 } catch (XmlPullParserException e) { 78 throw new RuntimeException("Error parsing alias", e); 79 } catch (IOException e) { 80 throw new RuntimeException("Error parsing alias", e); 81 } finally { 82 if (parser != null) parser.close(); 83 } 84 } 85 parseAlias(XmlPullParser parser)86 private Intent parseAlias(XmlPullParser parser) 87 throws XmlPullParserException, IOException { 88 AttributeSet attrs = Xml.asAttributeSet(parser); 89 90 Intent intent = null; 91 92 int type; 93 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT 94 && type != XmlPullParser.START_TAG) { 95 } 96 97 String nodeName = parser.getName(); 98 if (!"alias".equals(nodeName)) { 99 throw new RuntimeException( 100 "Alias meta-data must start with <alias> tag; found" 101 + nodeName + " at " + parser.getPositionDescription()); 102 } 103 104 int outerDepth = parser.getDepth(); 105 while ((type=parser.next()) != XmlPullParser.END_DOCUMENT 106 && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) { 107 if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) { 108 continue; 109 } 110 111 nodeName = parser.getName(); 112 if ("intent".equals(nodeName)) { 113 Intent gotIntent = Intent.parseIntent(getResources(), parser, attrs); 114 if (intent == null) intent = gotIntent; 115 } else { 116 XmlUtils.skipCurrentTag(parser); 117 } 118 } 119 120 return intent; 121 } 122 123 } 124