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<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">Android 开发技巧汇总 (1)</div><div class="t m0 x2 h4 y3 ff3 fs1 fc1 sc0 ls0 ws0"> <<android 开发技巧总汇 1>></div><div class="t m0 x3 h5 y4 ff2 fs3 fc1 sc0 ls0 ws0">目录</div><div class="t m0 x4 h6 y5 ff1 fs4 fc0 sc0 ls0 ws0"> <<android 开发技巧总汇 1>>..........................................................................................................1</div><div class="t m0 x5 h6 y6 ff1 fs4 fc0 sc0 ls0 ws0">1. 入门实例剖析 1......................................................................................................................2</div><div class="t m0 x5 h6 y7 ff1 fs4 fc0 sc0 ls0 ws0">2.在测试时,如何实现一个提示.................................................................................................8</div><div class="t m0 x5 h6 y8 ff1 fs4 fc0 sc0 ls0 ws0">3.可以使用 AlertDialog.Builder 才产生一个提示框...............................................................9</div><div class="t m0 x5 h6 y9 ff1 fs4 fc0 sc0 ls0 ws0">4. menu 的用法.........................................................................................................................10</div><div class="t m0 x6 h6 ya ff1 fs4 fc0 sc0 ls0 ws0">1. 简单的代码...................................................................................................................10</div><div class="t m0 x6 h6 yb ff1 fs4 fc0 sc0 ls0 ws0">2. menu 实现的两种方法.................................................................................................11</div><div class="t m0 x5 h6 yc ff1 fs4 fc0 sc0 ls0 ws0">5.Activity 的切换（含 Bundle 传值）....................................................................................14</div><div class="t m0 x6 h6 yd ff1 fs4 fc0 sc0 ls0 ws0">1. 代码2222..........................................................................................................................14</div><div class="t m0 x6 h6 ye ff1 fs4 fc0 sc0 ls0 ws0">2. 详解:.............................................................................................................................16</div><div class="t m0 x5 h7 yf ff1 fs4 fc0 sc0 ls0 ws0">6.AndroidUILayout................................................................................................................20</div><div class="t m0 x6 h7 y10 ff1 fs4 fc0 sc0 ls0 ws0">1. AbsoluteLayout.............................................................................................................20</div><div class="t m0 x5 h6 y11 ff1 fs4 fc0 sc0 ls0 ws0">7. Tab 以及2HostTab 操作.........................................................................................................21</div><div class="t m0 x5 h6 y12 ff1 fs4 fc0 sc0 ls0 ws0">8. List (图片/按钮/标题/文本).................................................................................................28</div><div class="t m0 x6 h6 y13 ff1 fs4 fc0 sc0 ls0 ws0">LIST 例一..........................................................................................................................28</div><div class="t m0 x6 h6 y14 ff1 fs4 fc0 sc0 ls0 ws0">LIST 例二..........................................................................................................................37</div><div class="t m0 x6 h6 y15 ff1 fs4 fc0 sc0 ls0 ws0">LIST 例三..........................................................................................................................41</div><div class="t m0 x5 h6 y16 ff1 fs4 fc0 sc0 ls0 ws0">9. 调用浏览器2载入某网址.....................................................................................................44</div><div class="t m0 x5 h6 y17 ff1 fs4 fc0 sc0 ls0 ws0">10.监控应用程序包的安装&删除..........................................................................................44</div><div class="t m0 x6 h6 y18 ff2 fs4 fc0 sc0 ls0 ws0">方法一:..............................................................................................................................44</div><div class="t m0 x6 h6 y19 ff2 fs4 fc0 sc0 ls0 ws0">方法二:..............................................................................................................................47</div><div class="t m0 x5 h6 y1a ff1 fs4 fc0 sc0 ls0 ws0">11. 使用 Toast 输出一个字符串...............................................................................................52</div><div class="t m0 x5 h6 y1b ff1 fs4 fc0 sc0 ls0 ws0">12. 把一个字符串写进文件.....................................................................................................52</div><div class="t m0 x5 h6 y1c ff1 fs4 fc0 sc0 ls0 ws0">13. 把文件内容读出到一个字符串.........................................................................................54</div><div class="t m0 x5 h6 y1d ff1 fs4 fc0 sc0 ls0 ws0">14. 调用 Android installer 安装和卸载程序...........................................................................55</div><div class="t m0 x5 h6 y1e ff1 fs4 fc0 sc0 ls0 ws0">15. 结束某个进程.....................................................................................................................56</div><div class="t m0 x5 h6 y1f ff1 fs4 fc0 sc0 ls0 ws0">16. 设置默认来电铃声.............................................................................................................56</div><div class="t m0 x5 h6 y20 ff1 fs4 fc0 sc0 ls0 ws0">17. 开机自启动.........................................................................................................................57</div><div class="t m0 x5 h6 y21 ff1 fs4 fc0 sc0 ls0 ws0">18. 线程与子线程.....................................................................................................................58</div><div class="t m0 x6 h6 y22 ff1 fs4 fc0 sc0 ls0 ws0">handlerMessage 实例........................................................................................................59</div><div class="t m0 x5 h7 y23 ff1 fs4 fc0 sc0 ls0 ws0">19. Service.................................................................................................................................60</div><div class="t m0 x6 h6 y24 ff1 fs4 fc0 sc0 ls0 ws0">1. 什么是 Service..............................................................................................................60</div><div class="t m0 x6 h6 y25 ff1 fs4 fc0 sc0 ls0 ws0">2. 如何使用 Service..........................................................................................................61</div><div class="t m0 x6 h6 y26 ff1 fs4 fc0 sc0 ls0 ws0">3. Service 的生命周期......................................................................................................66</div><div class="t m0 x5 h6 y27 ff2 fs4 fc0 sc0 ls0 ws0">附) 常用界面截图:...................................................................................................................67</div><div class="t m0 x6 h6 y28 ff2 fs4 fc0 sc0 ls0 ws0">提示 1................................................................................................................................67</div><div class="t m0 x6 h6 y29 ff2 fs4 fc0 sc0 ls0 ws0">提示 2................................................................................................................................68</div><div class="t m0 x6 h6 y2a ff2 fs4 fc0 sc0 ls0 ws0">菜单2..................................................................................................................................68</div><div class="t m0 x7 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">作者 ruin: craining@163.com</div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div> </body> </html>

<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">Android 开发技巧汇总 (1)</div><div class="t m0 x4 h8 y2c ff3 fs5 fc0 sc0 ls0 ws0">1. 入门实例剖析 1</div><div class="t m0 x4 h6 y2d ff2 fs4 fc0 sc0 ls0 ws0">开卷语</div><div class="t m0 x4 h6 y2e ff2 fs4 fc0 sc0 ls0 ws0">俗话说，“熟读唐诗三百首，不会作诗也会吟”。最近收集了很多 Android 的示例代码，从这</div><div class="t m0 x4 h6 y2f ff2 fs4 fc0 sc0 ls0 ws0">些代码的阅读和实验中学习到很多知识，从而产生写这个系列的打算，目标就是一步步跟</div><div class="t m0 x4 h6 y30 ff2 fs4 fc0 sc0 ls0 ws0">着实例进行动手实作，真正从“做”中体会和学习 Android 开发。</div><div class="t m0 x4 h6 y31 ff1 fs4 fc0 sc0 ls0 ws0"> 本文目标是 Android 自带的一个范例程序：记事本， </div><div class="t m0 x4 h6 y32 ff2 fs4 fc0 sc0 ls0 ws0">预备知识</div><div class="t m0 x4 h6 y33 ff2 fs4 fc0 sc0 ls0 ws0">搭建开发环境，尝试编写”Hello World，了解 Android 的基本概念，熟悉 Android 的 API(官</div><div class="t m0 x4 h6 y34 ff2 fs4 fc0 sc0 ls0 ws0">方文档中都有，不赘述)。</div><div class="t m0 x4 h6 y35 ff2 fs4 fc0 sc0 ls0 ws0">程序截图</div><div class="t m0 x4 h6 y36 ff2 fs4 fc0 sc0 ls0 ws0">先来简单了解下程序运行的效果</div><div class="t m0 x8 h7 y37 ff1 fs4 fc0 sc0 ls0 ws0"> 1 2</div><div class="t m0 x7 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">作者 ruin: craining@163.com</div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>

<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/bg3.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">Android 开发技巧汇总 (1)</div><div class="t m0 x9 h9 y38 ff1 fs0 fc0 sc0 ls0 ws0"> 3 4</div><div class="t m0 x4 h6 y39 ff2 fs4 fc0 sc0 ls0 ws0">程序入口点</div><div class="t m0 x4 h6 y3a ff2 fs4 fc0 sc0 ls0 ws0">类似于 win32 程序里的 WinMain 函数，Android 自然也有它的程序入口点。它通过在</div><div class="t m0 x4 h6 y3b ff1 fs4 fc0 sc0 ls0 ws0">AndroidManifest.xml 文件中配置来指明，可以看到名为 NotesList 的 activity 节点下有这样</div><div class="t m0 x4 h6 y3c ff2 fs4 fc0 sc0 ls0 ws0">一个 intent-filter,其 action 为 android.intent.action.MAIN,</div><div class="t m0 x4 h6 y3d ff1 fs4 fc0 sc0 ls0 ws0">Category 指定为 android.intent.category.LAUNCHER, 这就指明了这个 activity 是作为入口</div><div class="t m0 x4 h6 y3e ff1 fs4 fc0 sc0 ls0 ws0">activity，系统查找到它后，就会创建这个 activity 实例来运行，若未发现就不启动(你可以</div><div class="t m0 x4 h6 y3f ff2 fs4 fc0 sc0 ls0 ws0">把 MAIN 改名字试试)。</div><div class="t m0 x4 h7 y40 ff1 fs4 fc0 sc0 ls0 ws0"><intent-filter></div><div class="t m0 x4 h7 y41 ff1 fs4 fc0 sc0 ls0 ws0"><action android:name="android.intent.action.MAIN"</div><div class="t m0 x4 h7 y42 ff1 fs4 fc0 sc0 ls0 ws0">/></div><div class="t m0 x4 h7 y43 ff1 fs4 fc0 sc0 ls0 ws0"><category android:name="android.intent.category.LAUNCHER"</div><div class="t m0 x4 h7 y44 ff1 fs4 fc0 sc0 ls0 ws0">/></div><div class="t m0 x4 h7 y45 ff1 fs4 fc0 sc0 ls0 ws0"></intent-filter></div><div class="t m0 x4 h6 y46 ff6 fs4 fc0 sc0 ls0 ws0">NotesList 详解</div><div class="t m0 x4 h6 y47 ff2 fs4 fc0 sc0 ls0 ws0">就从入口点所在的 activity(见图 1)开始，可以看到这个 activity 最重要的功能就是显示日志</div><div class="t m0 x4 ha y48 ff2 fs4 fc0 sc0 ls0 ws0">列表。这个程序的日志都存放在 Sqlite 数据库中，因此需要读取出所有的日志记录并显示。</div><div class="t m0 x4 ha y49 ff2 fs4 fc0 sc0 ls0 ws0">先来看两个重要的私有数据，第一个 PROJECTION 字段指明了“日志列表“所关注的数据库</div><div class="t m0 x4 ha y4a ff2 fs4 fc0 sc0 ls0 ws0">中的字段（即只需要 ID 和 Title 就可以了）。</div><div class="t m0 x7 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">作者 ruin: craining@163.com</div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>

<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/bg4.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">Android 开发技巧汇总 (1)</div><div class="t m0 x4 h7 y4b ff1 fs4 fc0 sc0 ls0 ws0">private</div><div class="t m0 x4 h7 y4c ff1 fs4 fc0 sc0 ls0 ws0">static</div><div class="t m0 x4 h7 y4d ff1 fs4 fc0 sc0 ls0 ws0">final String[] PROJECTION =</div><div class="t m0 x4 h7 y4e ff1 fs4 fc0 sc0 ls0 ws0">new String[] {</div><div class="t m0 x4 h7 y4f ff1 fs4 fc0 sc0 ls0 ws0"> Notes._ID, // 0</div><div class="t m0 x4 h7 y50 ff1 fs4 fc0 sc0 ls0 ws0"> Notes.TITLE, // 1</div><div class="t m0 x4 h7 y51 ff1 fs4 fc0 sc0 ls0 ws0"> };</div><div class="t m0 x4 ha y52 ff7 fs4 fc0 sc0 ls0 ws0">第二个字段 COLUMN_INDEX_TITLE 指明 title 字段在数据表中的索引。</div><div class="t m0 x4 h7 y53 ff1 fs4 fc0 sc0 ls0 ws0">private</div><div class="t m0 x4 h7 y54 ff1 fs4 fc0 sc0 ls0 ws0">static</div><div class="t m0 x4 h7 y55 ff1 fs4 fc0 sc0 ls0 ws0">final</div><div class="t m0 x4 h7 y56 ff1 fs4 fc0 sc0 ls0 ws0">int COLUMN_INDEX_TITLE =</div><div class="t m0 x4 h7 y57 ff1 fs4 fc0 sc0 ls0 ws0">1;</div><div class="t m0 x4 ha y58 ff2 fs4 fc0 sc0 ls0 ws0">然后就进入第一个调用的函数 onCreate。</div><div class="t m0 x4 h7 y59 ff1 fs4 fc0 sc0 ls0 ws0"> Intent intent = getIntent();</div><div class="t m0 x4 h7 y5a ff1 fs4 fc0 sc0 ls0 ws0"> if (intent.getData() ==</div><div class="t m0 x4 h7 y5b ff1 fs4 fc0 sc0 ls0 ws0">null) </div><div class="t m0 x4 h7 y5c ff1 fs4 fc0 sc0 ls0 ws0"> {</div><div class="t m0 x4 h7 y5d ff1 fs4 fc0 sc0 ls0 ws0"> intent.setData(Notes.CONTENT_URI);</div><div class="t m0 x4 h7 y5e ff1 fs4 fc0 sc0 ls0 ws0"> }</div><div class="t m0 x4 ha y3a ff1 fs4 fc0 sc0 ls0 ws0"> 因为 NotesList 这个 activity 是系统调用的，此时的 intent 是不带数据和操作类型的，系</div><div class="t m0 x4 ha y3b ff2 fs4 fc0 sc0 ls0 ws0">统 只 是 在 其 中 指 明 了 目 标 组 件 是 Notelist ， 所 以 这 里 把 ” content://</div><div class="t m0 x4 ha y3c ff1 fs4 fc0 sc0 ls0 ws0">com.google.provider.NotePad/notes保存到 intent 里面，这个 URI 地址指明了数据库中的数</div><div class="t m0 x4 ha y3d ff2 fs4 fc0 sc0 ls0 ws0">据表名（参见以后的 NotePadProvider 类），也就是保存日志的数据表 notes。</div><div class="t m0 x4 h7 y5f ff1 fs4 fc0 sc0 ls0 ws0"> Cursor cursor = managedQuery(getIntent().getData(), PROJECTION, null, null,</div><div class="t m0 x4 h7 y60 ff1 fs4 fc0 sc0 ls0 ws0">Notes.DEFAULT_SORT_ORDER);</div><div class="t m0 x4 ha y61 ff1 fs4 fc0 sc0 ls0 ws0"> 然后调用 managedQuery 函数查询出所有的日志信息，这里第一个参数就是上面设置的”</div><div class="t m0 x4 ha y62 ff1 fs4 fc0 sc0 ls0 ws0">content:// com.google.provider.NotePad/notes这个 URI，即 notes 数据表。PROJECTION 字</div><div class="t m0 x4 ha y63 ff7 fs4 fc0 sc0 ls0 ws0">段指明了结果中所需要的字段，Notes.DEFAULT_SORT_ORDER 指明了结果的排序规则。</div><div class="t m0 x4 ha y64 ff2 fs4 fc0 sc0 ls0 ws0">实际上 managedQuery 并没有直接去查询数据库，而是通过 Content Provider 来完成实际的</div><div class="t m0 x4 ha y65 ff2 fs4 fc0 sc0 ls0 ws0">数据库操作，这样就实现了逻辑层和数据库层的分离。</div><div class="t m0 x4 h7 y44 ff1 fs4 fc0 sc0 ls0 ws0">SimpleCursorAdapter adapter =</div><div class="t m0 x4 h7 y45 ff1 fs4 fc0 sc0 ls0 ws0">new SimpleCursorAdapter(this, R.layout.noteslist_item, cursor,</div><div class="t m0 x4 h7 y66 ff1 fs4 fc0 sc0 ls0 ws0"> new String[] { Notes.TITLE }, new</div><div class="t m0 x4 h7 y67 ff1 fs4 fc0 sc0 ls0 ws0">int[] { android.R.id.text1 });</div><div class="t m0 x4 h7 y68 ff1 fs4 fc0 sc0 ls0 ws0"> setListAdapter(adapter);</div><div class="t m0 x4 ha y69 ff1 fs4 fc0 sc0 ls0 ws0"> 查询出日志列表后，构造一个 CursorAdapter，并将其作为 List View 的数据源，从而在</div><div class="t m0 x4 ha y49 ff2 fs4 fc0 sc0 ls0 ws0">界面上显示出日志列表。可以看到，第二个参数是 R.layout.noteslist_item，打开对应的</div><div class="t m0 x4 h6 y4a ff1 fs4 fc0 sc0 ls0 ws0">noteslist_item.xml 文件，</div><div class="t m0 x4 h7 y6a ff1 fs4 fc0 sc0 ls0 ws0"><TextView xmlns:android="http://schemas.android.com/apk/res/android"</div><div class="t m0 x7 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">作者 ruin: craining@163.com</div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>

<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/628d0e0f9ca87e087f58edc7/bg5.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">Android 开发技巧汇总 (1)</div><div class="t m0 x4 h7 y4b ff1 fs4 fc0 sc0 ls0 ws0"> android:id="@android:id/text1"</div><div class="t m0 x4 h7 y4c ff1 fs4 fc0 sc0 ls0 ws0"> android:layout_width="fill_parent"</div><div class="t m0 x4 h7 y4d ff1 fs4 fc0 sc0 ls0 ws0"> android:layout_height="?android:attr/listPreferredItemHeight"</div><div class="t m0 x4 h7 y4e ff1 fs4 fc0 sc0 ls0 ws0"> android:textAppearance="?android:attr/textAppearanceLarge"</div><div class="t m0 x4 h7 y4f ff1 fs4 fc0 sc0 ls0 ws0"> android:gravity="center_vertical"</div><div class="t m0 x4 h7 y50 ff1 fs4 fc0 sc0 ls0 ws0"> android:paddingLeft="5dip"</div><div class="t m0 x4 h7 y51 ff1 fs4 fc0 sc0 ls0 ws0"> android:singleLine="true"</div><div class="t m0 x4 h7 y6b ff1 fs4 fc0 sc0 ls0 ws0">/></div><div class="t m0 x4 ha y52 ff1 fs4 fc0 sc0 ls0 ws0"> 就是用来显示一条日志记录的 TextView,最后两个字段指明了实际的字段映射关系，通</div><div class="t m0 x4 ha y6c ff2 fs4 fc0 sc0 ls0 ws0">过这个 TextView 来显示一条日志记录的 title 字段。</div><div class="t m0 x4 ha y6d ff7 fs4 fc0 sc0 ls0 ws0">处理“选择日志”事件</div><div class="t m0 x4 ha y6e ff7 fs4 fc0 sc0 ls0 ws0">既然有了“日志列表”，就自然要考虑如何处理某一条日志的单击事件，这通过重载</div><div class="t m0 x4 ha y58 ff1 fs4 fc0 sc0 ls0 ws0">onListItemClick 方法来完成，</div><div class="t m0 x4 h7 y59 ff1 fs4 fc0 sc0 ls0 ws0"> @Override</div><div class="t m0 x4 h7 y5a ff1 fs4 fc0 sc0 ls0 ws0"> protected</div><div class="t m0 x4 h7 y5b ff1 fs4 fc0 sc0 ls0 ws0">void onListItemClick(ListView l, View v, int position, long id) {</div><div class="t m0 x4 h7 y5c ff1 fs4 fc0 sc0 ls0 ws0"> Uri uri = ContentUris.withAppendedId(getIntent().getData(), id);</div><div class="t m0 x4 h7 y5d ff1 fs4 fc0 sc0 ls0 ws0"> </div><div class="t m0 x4 h7 y5e ff1 fs4 fc0 sc0 ls0 ws0"> String action = getIntent().getAction();</div><div class="t m0 x4 h7 y6f ff1 fs4 fc0 sc0 ls0 ws0"> if (Intent.ACTION_PICK.equals(action) || Intent.ACTION_GET_CONTENT.equals(action))</div><div class="t m0 x4 h7 y70 ff1 fs4 fc0 sc0 ls0 ws0">{</div><div class="t m0 x4 h7 y71 ff1 fs4 fc0 sc0 ls0 ws0"> // The caller is waiting for us to return a note selected by</div><div class="t m0 x4 h7 y72 ff1 fs4 fc0 sc0 ls0 ws0"> // the user. The have clicked on one, so return it now.</div><div class="t m0 x4 h7 y73 ff1 fs4 fc0 sc0 ls0 ws0"> setResult(RESULT_OK, new Intent().setData(uri));</div><div class="t m0 x4 h7 y5f ff1 fs4 fc0 sc0 ls0 ws0"> } else {</div><div class="t m0 x4 h7 y60 ff1 fs4 fc0 sc0 ls0 ws0"> // Launch activity to view/edit the currently selected item</div><div class="t m0 x4 h7 y74 ff1 fs4 fc0 sc0 ls0 ws0"> startActivity(new Intent(Intent.ACTION_EDIT, uri));</div><div class="t m0 x4 h7 y40 ff1 fs4 fc0 sc0 ls0 ws0"> }</div><div class="t m0 x4 h7 y41 ff1 fs4 fc0 sc0 ls0 ws0"> }</div><div class="t m0 x4 ha y65 ff1 fs4 fc0 sc0 ls0 ws0"> 首先通过”content:// com.google.provider.NotePad/notes和日志的 id 号拼接得到选中日志</div><div class="t m0 x4 ha y75 ff2 fs4 fc0 sc0 ls0 ws0">的真正 URI,然后创建一个新的 Intent,其操作类型为 Intent.ACTION_EDIT，数据域指出待编</div><div class="t m0 x4 ha y76 ff7 fs4 fc0 sc0 ls0 ws0">辑的日志 URI（这里只分析 else 块）。</div><div class="t m0 x4 ha y46 ff6 fs4 fc0 sc0 ls0 ws0">Intent 深度剖析</div><div class="t m0 x4 ha y47 ff7 fs4 fc0 sc0 ls0 ws0">那么，上面这句 startActivity(new Intent(Intent.ACTION_EDIT, uri))执行后会发生什么事情呢</div><div class="t m0 x4 ha y48 ff2 fs4 fc0 sc0 ls0 ws0">这时候 Android 系统就跳出来接管了，它会根据 intent 中的信息找到对应的 activity，在这</div><div class="t m0 x4 ha y69 ff2 fs4 fc0 sc0 ls0 ws0">里找到的是 NoteEditor 这个 activity，然后创建这个 activity 的实例并运行。</div><div class="t m0 x4 ha y4a ff7 fs4 fc0 sc0 ls0 ws0">那么，Android 又是如何找到 NoteEditor 这个对应的 activity 的呢？这就是 intent 发挥作用的</div><div class="t m0 x4 ha y77 ff2 fs4 fc0 sc0 ls0 ws0">时刻了。</div><div class="t m0 x7 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">作者 ruin: craining@163.com</div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>