Android API
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【Android API Demos】API Demo 初探
2012-02-23 20:52 2137人阅读 评论(0)收藏 举报
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首先声明,该文章为自己学习笔记,仅供参考,不保证所有文字均描述得当,欢迎指出不足和错误之处,再此感谢您的关注和阅读。如果有需要代码的可以留言,和我联系。
1.准备工作
首先,导入API Demos。File->new->project->android project->Creat project from existing source 选择API Demos.
导入的文件可以在sdk的文件里面找到,如XXX/android-8/samples.也可以直接下载如http://dl-ssl.google.com/android/repository/samples-2.2_r01-linux.zip
2.开始
根据那个图我们可以看见,API Demos把常用的一些功能都集成在这个里面了,所以我们只要一步一步来,就可以掌握的差不多了。
先看下AndroidMainifest.xml
- <activity android:name="ApiDemos">
- <intent-filter>
- <action android:name="android.intent.action.MAIN" />
- <category android:name="android.intent.category.DEFAULT" />
- <category android:name="android.intent.category.LAUNCHER" />
- </intent-filter>
- </activity>
<activity android:name="ApiDemos"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.DEFAULT" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>
发现首先启动的是ApiDemos,所以我们的目光集中在com.example.android.apis/ApiDemos.java里面
- /*
- * 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 com.example.android.apis;
- import android.app.ListActivity;
- import android.content.Intent;
- import android.content.pm.PackageManager;
- import android.content.pm.ResolveInfo;
- import android.os.Bundle;
- import android.view.View;
- import android.widget.ListView;
- import android.widget.SimpleAdapter;
- import java.text.Collator;
- import java.util.ArrayList;
- import java.util.Collections;
- import java.util.Comparator;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- /*
- * 主要是通过对Activity的label信息进行分析,从而将Activity进行分类并通过ListView显示出来。
- * 例如<activity android:name=".app.HelloWorld" android:label="@string/activity_hello_world">的label为
- * App/Activity/Hello World,程序运行的结果是一级目录含有App选项,点击App出现的二级目录含有Activity选项,
- * 点击Activity出现的三级目录含有Hello World选项,点击Hello World会出现Hello World这个Activity运行的结果
- */
- public class ApiDemos extends ListActivity {
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- Intent intent = getIntent();
- /*
- * 当程序启动要显示一级目录(App, Content, ...)时,Intent对象里绑定的附加信息path为空
- * 当点击一级目录选项进入二级目录(例如App下的Activity, Alarm, ...)时,path就不为空了(例如为App)
- */
- String path = intent.getStringExtra("com.example.android.apis.Path");
- if (path == null) {
- path = "";
- }
- // 通过adapter为当前ListActivity传递数据
- setListAdapter(new SimpleAdapter(this, getData(path),
- android.R.layout.simple_list_item_1, new String[] { "title" },
- new int[] { android.R.id.text1 }));
- // 允许当前ListView可以根据用户输入的值进行过滤
- getListView().setTextFilterEnabled(true);
- }
- /*
- * 获取应用列表,包括一级目录,二级目录,等等
- */
- protected List getData(String prefix) {
- List<Map> myData = new ArrayList<Map>();
- /*
- * 获取在AndroidManifest.xml文件中的Intent Filter里配置了
- * Intent.ACTION_MAIN和Intent.CATEGORY_SAMPLE_CODE的所有Activity
- */
- Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
- mainIntent.addCategory(Intent.CATEGORY_SAMPLE_CODE);
- PackageManager pm = getPackageManager();
- List<ResolveInfo> list = pm.queryIntentActivities(mainIntent, 0);
- if (null == list)
- return myData;
- String[] prefixPath;
- // 当要显示一级目录时,prefix为空字符串;当点击App进入要显示二级目录时,prefix为App;
- if (prefix.equals("")) {
- prefixPath = null;
- } else {
- prefixPath = prefix.split("/");
- }
- int len = list.size();
- Map<String, Boolean> entries = new HashMap<String, Boolean>();
- for (int i = 0; i < len; i++) {
- ResolveInfo info = list.get(i);
- // 获取Activity的label信息,例如App/Activity/Hello World
- CharSequence labelSeq = info.loadLabel(pm);
- String label = labelSeq != null
- ? labelSeq.toString()
- : info.activityInfo.name;
- if (prefix.length() == 0 || label.startsWith(prefix)) {
- // 例如labelPath = [App, Activity, Hello World]
- String[] labelPath = label.split("/");
- // 例如要显示一级目录时nextLabel = "App",要显示二级目录时,nextLabel = "Activity"
- String nextLabel = prefixPath == null ? labelPath[0] : labelPath[prefixPath.length];
- // 当要显示的label为Activity而非目录时,需要为label绑定跳转到相关Activity的Intent
- if ((prefixPath != null ? prefixPath.length : 0) == labelPath.length - 1) {
- addItem(myData, nextLabel, activityIntent(
- info.activityInfo.applicationInfo.packageName,
- info.activityInfo.name));
- } else {
- if (entries.get(nextLabel) == null) {
- addItem(myData, nextLabel, browseIntent(prefix.equals("") ? nextLabel : prefix + "/" + nextLabel));
- entries.put(nextLabel, true);
- }
- }
- }
- }
- // 排序
- Collections.sort(myData, sDisplayNameComparator);
- return myData;
- }
- private final static Comparator<Map> sDisplayNameComparator = new Comparator<Map>() {
- private final Collator collator = Collator.getInstance();
- public int compare(Map map1, Map map2) {
- return collator.compare(map1.get("title"), map2.get("title"));
- }
- };
- /*
- * 为label绑定跳转到相关Activity的Intent
- */
- protected Intent activityIntent(String pkg, String componentName) {
- Intent result = new Intent();
- result.setClassName(pkg, componentName);
- return result;
- }
- /*
- * 为label绑定跳转到当前Activity的Intent,附加信息path为当前目录
- * 例如为Activity这个label绑定的Intent中附加值为App/Activity
- */
- protected Intent browseIntent(String path) {
- Intent result = new Intent();
- result.setClass(this, ApiDemos.class);
- result.putExtra("com.example.android.apis.Path", path);
- return result;
- }
- /*
- * 将符合条件的选项加入List中
- */
- protected void addItem(List<Map> data, String name, Intent intent) {
- Map<String, Object> temp = new HashMap<String, Object>();
- temp.put("title", name);
- temp.put("intent", intent);
- data.add(temp);
- }
- @Override
- protected void onListItemClick(ListView l, View v, int position, long id) {
- Map map = (Map) l.getItemAtPosition(position);
- Intent intent = (Intent) map.get("intent");
- startActivity(intent);
- }
- }
/* * 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 com.example.android.apis;import android.app.ListActivity;import android.content.Intent;import android.content.pm.PackageManager;import android.content.pm.ResolveInfo;import android.os.Bundle;import android.view.View;import android.widget.ListView;import android.widget.SimpleAdapter;import java.text.Collator;import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.HashMap;import java.util.List;import java.util.Map;/* * 主要是通过对Activity的label信息进行分析,从而将Activity进行分类并通过ListView显示出来。 * 例如<activity android:name=".app.HelloWorld" android:label="@string/activity_hello_world">的label为 * App/Activity/Hello World,程序运行的结果是一级目录含有App选项,点击App出现的二级目录含有Activity选项, * 点击Activity出现的三级目录含有Hello World选项,点击Hello World会出现Hello World这个Activity运行的结果 */public class ApiDemos extends ListActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Intent intent = getIntent(); /* * 当程序启动要显示一级目录(App, Content, ...)时,Intent对象里绑定的附加信息path为空 * 当点击一级目录选项进入二级目录(例如App下的Activity, Alarm, ...)时,path就不为空了(例如为App) */ String path = intent.getStringExtra("com.example.android.apis.Path"); if (path == null) { path = ""; } // 通过adapter为当前ListActivity传递数据 setListAdapter(new SimpleAdapter(this, getData(path), android.R.layout.simple_list_item_1, new String[] { "title" }, new int[] { android.R.id.text1 })); // 允许当前ListView可以根据用户输入的值进行过滤 getListView().setTextFilterEnabled(true); } /* * 获取应用列表,包括一级目录,二级目录,等等 */ protected List getData(String prefix) { List<Map> myData = new ArrayList<Map>(); /* * 获取在AndroidManifest.xml文件中的Intent Filter里配置了 * Intent.ACTION_MAIN和Intent.CATEGORY_SAMPLE_CODE的所有Activity */ Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_SAMPLE_CODE); PackageManager pm = getPackageManager(); List<ResolveInfo> list = pm.queryIntentActivities(mainIntent, 0); if (null == list) return myData; String[] prefixPath; // 当要显示一级目录时,prefix为空字符串;当点击App进入要显示二级目录时,prefix为App; if (prefix.equals("")) { prefixPath = null; } else { prefixPath = prefix.split("/"); } int len = list.size(); Map<String, Boolean> entries = new HashMap<String, Boolean>(); for (int i = 0; i < len; i++) { ResolveInfo info = list.get(i); // 获取Activity的label信息,例如App/Activity/Hello World CharSequence labelSeq = info.loadLabel(pm); String label = labelSeq != null ? labelSeq.toString() : info.activityInfo.name; if (prefix.length() == 0 || label.startsWith(prefix)) { // 例如labelPath = [App, Activity, Hello World] String[] labelPath = label.split("/"); // 例如要显示一级目录时nextLabel = "App",要显示二级目录时,nextLabel = "Activity" String nextLabel = prefixPath == null ? labelPath[0] : labelPath[prefixPath.length]; // 当要显示的label为Activity而非目录时,需要为label绑定跳转到相关Activity的Intent if ((prefixPath != null ? prefixPath.length : 0) == labelPath.length - 1) { addItem(myData, nextLabel, activityIntent( info.activityInfo.applicationInfo.packageName, info.activityInfo.name)); } else { if (entries.get(nextLabel) == null) { addItem(myData, nextLabel, browseIntent(prefix.equals("") ? nextLabel : prefix + "/" + nextLabel)); entries.put(nextLabel, true); } } } } // 排序 Collections.sort(myData, sDisplayNameComparator); return myData; } private final static Comparator<Map> sDisplayNameComparator = new Comparator<Map>() { private final Collator collator = Collator.getInstance(); public int compare(Map map1, Map map2) { return collator.compare(map1.get("title"), map2.get("title")); } }; /* * 为label绑定跳转到相关Activity的Intent */ protected Intent activityIntent(String pkg, String componentName) { Intent result = new Intent(); result.setClassName(pkg, componentName); return result; } /* * 为label绑定跳转到当前Activity的Intent,附加信息path为当前目录 * 例如为Activity这个label绑定的Intent中附加值为App/Activity */ protected Intent browseIntent(String path) { Intent result = new Intent(); result.setClass(this, ApiDemos.class); result.putExtra("com.example.android.apis.Path", path); return result; } /* * 将符合条件的选项加入List中 */ protected void addItem(List<Map> data, String name, Intent intent) { Map<String, Object> temp = new HashMap<String, Object>(); temp.put("title", name); temp.put("intent", intent); data.add(temp); } @Override protected void onListItemClick(ListView l, View v, int position, long id) { Map map = (Map) l.getItemAtPosition(position); Intent intent = (Intent) map.get("intent"); startActivity(intent); }}
上面代码内容参考 http://hunter2014.iteye.com/blog/778160
看了以后发现是不是真心的理解不了,没关系,继续往下看,我会从最简单的ListView开始一起学习,最后再回过头来看看这个程序,或许过上几天,几周,就很轻松了。下一天,准备从ListView开始学起。
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