Android開發之搜索框自動提示細節MatrixCursor學習

1，在ActionBar裡面加入搜索框

在ActionBar裡面加入搜索框是現在APP應用的常用做法。要想把搜索做好，可不是那麼容易。涉及到自動提示和真正的搜索。下圖是我對一個相對完整的搜索框涉及的元素關系做了一個圖，箭頭只表示它們之間有關系，不是類圖中的繼承。

一個Activity會有一個ActionBar，默認情況下。你可以在ActionBar裡面添加菜單條目。菜單條目可以設置標題，圖標以及關聯的ActionView，這裡我們關聯了一個SearchView。SearchView和SearchableInfo關聯，和搜索服務關聯。同時為了更好的處理關於SearchView的事件響應，我們抽象了一個控制類MovieSearch。它是邏輯控制中心，有搜索完了的跳轉SearchActivity（包含SearchFregment），也有內容提示。內容提示主要是根據輸入的字進行聯想，或者根據歷史記錄或者熱門搜索。所以這裡有個SearchHistory，它又和數據表相關。

vcHL0ru49sDgTWF0cml4Q3Vyc29yo6zL+dLUo6zO0sPHz+rPuLXEwcu94tXiuPbA4LXE08O3qKGjPC9wPgo8aDI+MqOsTWF0cml4Q3Vyc29yz+q94jwvaDI+CjxwPjxicj4KPC9wPgo8cD48L3A+CrzZyOfT0NK7uPbI58/CtcTK/b7dv+Kx7b3hubkKCjx0YWJsZSBib3JkZXI9"1" cellspacing="0" cellpadding="2" width="100%"> _id name price R.drawable.ic_launcher zhangsan 39 R.drawable.ic_launcher lisi 40 R.drawable.ic_launcher wangwu 41 R.drawable.ic_launcher zhaoliu 42
現在咱們就通過MatrixCursor這個東西，來虛構出一張上面那樣的表結構，下面通過一個例子，就可以完全理解MatrixCursor這個東西 見示例代碼如下： [java] view plaincopy

1. package com.test.matrixcursor;
3. import android.app.ListActivity;
4. import android.database.MatrixCursor;
5. import android.os.Bundle;
6. import android.support.v4.widget.SimpleCursorAdapter;
7. import android.view.View;
8. import android.widget.ListView;
9. import android.widget.Toast;
11. public class MainActivity extends ListActivity {
12. private static final String[] COLUMN_NAME = { "_id", "name", "price" };
13. private MatrixCursor matrixCursor;
15. @Override
16. protected void onCreate(Bundle savedInstanceState) {
17. super.onCreate(savedInstanceState);
18. createList();
19. //createList2();
20. }
22. private void createList() {
23. matrixCursor = new MatrixCursor(COLUMN_NAME, 1);
24. startManagingCursor(matrixCursor);
26. matrixCursor.addRow(new Object[] { R.drawable.ic_launcher, "zhangsan",
27. 39 });
28. matrixCursor
29. .addRow(new Object[] { R.drawable.ic_launcher, "lisi", 40 });
30. matrixCursor
31. .addRow(new Object[] { R.drawable.ic_launcher, "wangwu", 41 });
33. matrixCursor.addRow(new Object[] { R.drawable.ic_launcher, "zhaoliu",
34. 42 });
35. matrixCursor
36. .addRow(new Object[] { R.drawable.ic_launcher, "sunqi", 43 });
38. setListAdapter(new SimpleCursorAdapter(this, R.layout.activity_main,
39. matrixCursor, COLUMN_NAME, new int[] { R.id.icon, R.id.name,
40. R.id.price }));
41. }
43. private void createList2() {
44. matrixCursor = new MatrixCursor(COLUMN_NAME, 1);
45. startManagingCursor(matrixCursor);
47. MatrixCursor.RowBuilder builder1 = matrixCursor.newRow();
48. builder1.add(R.drawable.ic_launcher);
49. builder1.add("zhangsan");
50. builder1.add(39);
52. MatrixCursor.RowBuilder builder2 = matrixCursor.newRow();
53. builder2.add(R.drawable.ic_launcher);
54. builder2.add("lisi");
55. builder2.add(40);
57. MatrixCursor.RowBuilder builder3 = matrixCursor.newRow();
58. builder3.add(R.drawable.ic_launcher);
59. builder3.add("wangwu");
60. builder3.add(41);
62. setListAdapter(new SimpleCursorAdapter(this, R.layout.activity_main,
63. matrixCursor, COLUMN_NAME, new int[] { R.id.icon, R.id.name,
64. R.id.price }));
65. }
67. @Override
68. protected void onListItemClick(ListView l, View v, int position, long id) {
69. super.onListItemClick(l, v, position, id);
70. matrixCursor.moveToPosition(position);
71. StringBuilder builder = new StringBuilder();
72. builder.append("Name:")
73. .append(matrixCursor.getString(matrixCursor
74. .getColumnIndex("name"))).append("\n");
76. builder.append("Price:")
77. .append(matrixCursor.getString(matrixCursor
78. .getColumnIndex("price"))).append("\n");
80. Toast.makeText(getApplicationContext(), builder.toString(), 1000)
81. .show();
82. }
83. }
85. 
    實現步驟僅需3步，下面通過字符數組來說明： 步驟1.首先創建一個字符數組，且字符數組的值對應著表的字段，如下： String[] COLUMN_NAME = { "_id", "name", "price" }; 步驟2.利用MatrixCursor的構造方法，構造一個MatrixCursor，傳入的參數即是步驟1中創建的字段數組，如下： MatrixCursormatrixCursor=newMatrixCursor(COLUMN_NAME); 也可以指定初始大小，如： matrixCursor=newMatrixCursor( COLUMN_NAME, 10);
    步驟3. 通過matrixCursor 的addRow方法添加一行值，相當於向數據庫中插入一條記錄，如下： matrixCursor.addRow(new Object[] { R.drawable.ic_launcher, "zhangsan",39 });
    注：步驟3也可以通過構造一個MatrixCursor.RowBuilder來實現，也是相當於向數據庫中插入一條記錄，如下： MatrixCursor.RowBuilder builder1 = matrixCursor.newRow();
    builder1.add(R.drawable.ic_launcher);
    builder1.add("zhangsan");
    builder1.add(39);
    //builder1.add(399999); 通過上面三步即可完成MatrixCursor 的構造。從MatrixCursor 中取出數據的過程與Cursor相同，不再贅述！
    
    注釋：如果builder1對象add的數量大於字段的個數，即打開builder1.add(399999);注釋，那麼將會報以下錯誤：
    02-27 19:00:44.882: W/dalvikvm(29036): threadid=1: thread exiting with uncaught exception (group=0x41e689a8)
    02-27 19:00:44.882: W/dalvikvm(29036): threadid=1: uncaught exception occurred
    02-27 19:00:44.883: W/System.err(29036): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.matrixcursor/com.test.matrixcursor.MainActivity}:android.database.CursorIndexOutOfBoundsException: No more columns left.
    02-27 19:00:44.883: W/System.err(29036): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2356)
    02-27 19:00:44.883: W/System.err(29036): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2408)
    02-27 19:00:44.883: W/System.err(29036): at android.app.ActivityThread.access$600(ActivityThread.java:167)
    02-27 19:00:44.883: W/System.err(29036): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1378)
    02-27 19:00:44.883: W/System.err(29036): at android.os.Handler.dispatchMessage(Handler.java:107)
    02-27 19:00:44.883: W/System.err(29036): at android.os.Looper.loop(Looper.java:194)
    02-27 19:00:44.884: W/System.err(29036): at android.app.ActivityThread.main(ActivityThread.java:5405)
    02-27 19:00:44.884: W/System.err(29036): at java.lang.reflect.Method.invokeNative(Native Method)
    02-27 19:00:44.884: W/System.err(29036): at java.lang.reflect.Method.invoke(Method.java:525)
    02-27 19:00:44.884: W/System.err(29036): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:838)
    02-27 19:00:44.884: W/System.err(29036): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
    02-27 19:00:44.884: W/System.err(29036): at dalvik.system.NativeStart.main(Native Method)
    02-27 19:00:44.886: W/System.err(29036): Caused by: android.database.CursorIndexOutOfBoundsException: No more columns left.
    02-27 19:00:44.887: W/System.err(29036): at android.database.MatrixCursor$RowBuilder.add(MatrixCursor.java:206)
    02-27 19:00:44.887: W/System.err(29036): at com.test.matrixcursor.MainActivity.createList(MainActivity.java:46)
    02-27 19:00:44.888: W/System.err(29036): at com.test.matrixcursor.MainActivity.onCreate(MainActivity.java:20)
    02-27 19:00:44.889: W/System.err(29036): at android.app.Activity.performCreate(Activity.java:5127)
    02-27 19:00:44.889: W/System.err(29036): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1151)
    02-27 19:00:44.890: W/System.err(29036): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2320) 程序運行結果：