Android：带有CheckBox的ListView,从SQLite数据库填充不太正常

Android 前端之家
前端之家收集整理的这篇文章主要介绍了Android：带有CheckBox的ListView,从SQLite数据库填充不太正常，前端之家小编觉得挺不错的，现在分享给大家，也给大家做个参考。
与此处的其他几篇文章一样,我正在尝试创建一个ListView,其中包含每行的CheckBox,并使用sqlite数据库存储选择的当前状态.

从http://appfulcrum.com/?p=351的示例开始,这个示例并不完全正常,我创建了一个创建数据库的简单应用程序,用20个项目填充它,并显示列表.

它成功检索状态并存储选择的状态.

但是,如果我更改它,它无法正确显示CheckBox状态,滚动到列表的另一端,然后向后滚动.例如如果我选择第一个CheckBox,滚动到底部,然后回到顶部,不再设置CheckBox.这是在Android 2.1三星手机上运行.

如果我返回主屏幕,返回列表,CheckBox已正确设置,因此数据库确实已更新.

该示例扩展了SimpleCursorAdapter,并且getView()根据表中选择列的值,根据需要使用true或false调用setChecked().

以下是所有来源.

我当然很感激被告知,“呃,这是你的问题……”

CustomListViewDB.java

  1. // src/CustomListViewDB.java
  2. package com.appfulcrum.blog.examples.listviewcustomdb;
  3.  
  4. import android.app.ListActivity;
  5. import android.database.Cursor;
  6. import android.database.sqlException;
  7. import android.os.AsyncTask;
  8. import android.os.Bundle;
  9. import android.view.View;
  10. import android.view.View.OnClickListener;
  11. import android.widget.Button;
  12. import android.widget.ListView;
  13. import android.widget.Toast;
  14.  
  15. public class CustomListViewDB extends ListActivity {
  16.  
  17.     private ListView mainListView = null;
  18.     CustomsqlCursorAdapter adapter = null;
  19.     private sqlHelper dbHelper = null;
  20.     private Cursor currentCursor = null;
  21.  
  22.     private ListView listView = null;
  23.  
  24.     /** Called when the activity is first created. */
  25.     @Override
  26.     public void onCreate(Bundle savedInstanceState) {
  27.         super.onCreate(savedInstanceState);
  28.         setContentView(R.layout.simple);
  29.  
  30.         if (this.dbHelper == null) {
  31.             this.dbHelper = new sqlHelper(this);
  32.  
  33.         }
  34.  
  35.         listView = getListView();
  36.         listView.setItemsCanFocus(false);
  37.         listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
  38.         //listView.setClickable(true);
  39.  
  40.         Button btnClear = (Button) findViewById(R.id.btnClear);
  41.         btnClear.setOnClickListener(new OnClickListener() {
  42.  
  43.             public void onClick(View v) {
  44.                 Toast.makeText(getApplicationContext()," You clicked Clear button",Toast.LENGTH_SHORT).show();
  45.                 ClearDBSelections();
  46.             }
  47.         });
  48.  
  49.         new SelectDataTask().execute();
  50.  
  51.         this.mainListView = getListView();
  52.  
  53.         mainListView.setCacheColorHint(0);
  54.  
  55.     }
  56.  
  57.     @Override
  58.     protected void onRestart() {
  59.         super.onRestart();
  60.         new SelectDataTask().execute();
  61.     }
  62.  
  63.     @Override
  64.     protected void onPause() {
  65.  
  66.         super.onPause();
  67.         this.dbHelper.close();
  68.     }
  69.  
  70.     protected void ClearDBSelections() {
  71.  
  72.         this.adapter.ClearSelections();
  73.  
  74.     }
  75.  
  76.     private class SelectDataTask extends AsyncTask<Void,Void,String> {
  77.  
  78.         protected String doInBackground(Void... params) {
  79.  
  80.             try {
  81.  
  82.                 CustomListViewDB.this.dbHelper.createDatabase(dbHelper.dbsqlite);
  83.                 CustomListViewDB.this.dbHelper.openDataBase();
  84.  
  85.                 CustomListViewDB.this.currentCursor = CustomListViewDB.this.dbHelper
  86.                         .getCursor();
  87.  
  88.             } catch (sqlException sqle) {
  89.  
  90.                 throw sqle;
  91.  
  92.             }
  93.             return null;
  94.         }
  95.  
  96.         // can use UI thread here
  97.         protected void onPostExecute(final String result) {
  98.  
  99.             startManagingCursor(CustomListViewDB.this.currentCursor);
  100.             int[] listFields = new int[] { R.id.txtTitle };
  101.             String[] dbColumns = new String[] { sqlHelper.COLUMN_TITLE };
  102.  
  103.             CustomListViewDB.this.adapter = new CustomsqlCursorAdapter(
  104.                     CustomListViewDB.this,R.layout.single_item,CustomListViewDB.this.currentCursor,dbColumns,listFields,CustomListViewDB.this.dbHelper);
  105.             setListAdapter(CustomListViewDB.this.adapter);
  106.  
  107.         }
  108.     }
  109.  
  110. }

CustomsqlCursorAdapter.java

  1. // src/CustomsqlCursorAdapter.java
  2.  
  3. package com.appfulcrum.blog.examples.listviewcustomdb;
  4.  
  5. import android.content.ContentValues;
  6. import android.content.Context;
  7. import android.database.Cursor;
  8. import android.database.sqlException;
  9. import android.util.Log;
  10. import android.view.LayoutInflater;
  11. import android.view.View;
  12. import android.view.ViewGroup;
  13. import android.widget.CheckBox;
  14. import android.widget.CompoundButton;
  15. import android.widget.CompoundButton.OnCheckedChangeListener;
  16. import android.widget.SimpleCursorAdapter;
  17. import android.widget.TextView;
  18.  
  19. public class CustomsqlCursorAdapter extends SimpleCursorAdapter {
  20.     private Context mContext;
  21.  
  22.     private sqlHelper mDbHelper;
  23.     private Cursor mCurrentCursor;
  24.  
  25.     public CustomsqlCursorAdapter(Context context,int layout,Cursor c,String[] from,int[] to,sqlHelper dbHelper) {
  26.         super(context,layout,c,from,to);
  27.         this.mCurrentCursor = c;
  28.         this.mContext = context;
  29.         this.mDbHelper = dbHelper;
  30.  
  31.     }
  32.  
  33.     public View getView(int pos,View inView,ViewGroup parent) {
  34.         View v = inView;
  35.         if (v == null) {
  36.             LayoutInflater inflater = (LayoutInflater) mContext
  37.                     .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  38.             v = inflater.inflate(R.layout.single_item,null);
  39.         }
  40.  
  41.         if (!this.mCurrentCursor.moveToPosition(pos)) {
  42.             throw new sqlException("CustomsqlCursorAdapter.getView: Unable to move to position: "+pos);
  43.         }
  44.  
  45.         CheckBox cBox = (CheckBox) v.findViewById(R.id.bcheck);
  46.  
  47.         // save the row's _id value in the checkBox's tag for retrieval later
  48.         cBox.setTag(Integer.valueOf(this.mCurrentCursor.getInt(0)));
  49.  
  50.         if (this.mCurrentCursor.getInt(sqlHelper.COLUMN_SELECTED_idx) != 0) {
  51.             cBox.setChecked(true);
  52.             Log.w("sqlHelper","CheckBox true for pos "+pos+",id="+this.mCurrentCursor.getInt(0));
  53.         } else {
  54.             cBox.setChecked(false);
  55.             Log.w("sqlHelper","CheckBox false for pos "+pos+",id="+this.mCurrentCursor.getInt(0));
  56.         }
  57.         //cBox.setOnClickListener(this);
  58.         cBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
  59.  
  60.             @Override
  61.             public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
  62.  
  63.                 Log.w("sqlHelper","Selected a CheckBox and in onCheckedChanged: "+isChecked);
  64.  
  65.                 Integer _id = (Integer) buttonView.getTag();
  66.                 ContentValues values = new ContentValues();
  67.                 values.put(sqlHelper.COLUMN_SELECTED,isChecked ? Integer.valueOf(1) : Integer.valueOf(0));
  68.                 mDbHelper.dbsqlite.beginTransaction();
  69.                 try {
  70.                     if (mDbHelper.dbsqlite.update(sqlHelper.TABLE_NAME,values,"_id=?",new String[] { Integer.toString(_id) }) != 1) {
  71.                         throw new sqlException("onCheckedChanged Failed to update _id="+_id);
  72.                     }
  73.                     mDbHelper.dbsqlite.setTransactionSuccessful();
  74.                 } finally {
  75.                     mDbHelper.dbsqlite.endTransaction();
  76.                 }
  77.  
  78.                 Log.w("sqlHelper","-- _id="+_id+",isChecked="+isChecked);
  79.             }
  80.         });
  81.  
  82.         TextView txtTitle = (TextView) v.findViewById(R.id.txtTitle);
  83.         txtTitle.setText(this.mCurrentCursor.getString(this.mCurrentCursor
  84.                 .getColumnIndex(sqlHelper.COLUMN_TITLE)));
  85.  
  86.         return (v);
  87.     }
  88.  
  89.     public void ClearSelections() {
  90.         this.mDbHelper.clearSelections();
  91.         this.mCurrentCursor.requery();
  92.  
  93.     }
  94. }

ListViewWithDBActivity.java

  1. package com.appfulcrum.blog.examples.listviewcustomdb;
  2.  
  3. import android.app.Activity;
  4. import android.os.Bundle;
  5.  
  6. public class ListViewWithDBActivity extends Activity {
  7.     /** Called when the activity is first created. */
  8.     @Override
  9.     public void onCreate(Bundle savedInstanceState) {
  10.         super.onCreate(savedInstanceState);
  11.         setContentView(R.layout.main);
  12.     }
  13. }

提供sqlHelper

  1. // sqlHelper.java
  2.  
  3. package com.appfulcrum.blog.examples.listviewcustomdb;
  4.  
  5. import android.content.ContentValues;
  6. import android.content.Context;
  7. import android.database.Cursor;
  8. import android.database.sqlException;
  9. import android.database.sqlite.sqliteDatabase;
  10. import android.database.sqlite.sqliteOpenHelper;
  11. import android.database.sqlite.sqliteQueryBuilder;
  12. import android.database.sqlite.sqliteStatement;
  13. import android.util.Log;
  14.  
  15. public class sqlHelper extends sqliteOpenHelper {
  16.     private static final String DATABASE_PATH = "/data/data/com.appfulcrum.blog.examples.listviewcustomdb/databases/";
  17.  
  18.     public static final String DATABASE_NAME = "TODOList";
  19.  
  20.     public static final String TABLE_NAME = "ToDoItems";
  21.     public static final int ToDoItems_VERSION = 1;
  22.  
  23.     public static final String COLUMN_ID = "_id";               // 0
  24.     public static final String COLUMN_TITLE = "title";          // 1
  25.     public static final String COLUMN_NAME_DESC = "description";// 2
  26.     public static final String COLUMN_SELECTED = "selected";    // 3
  27.     public static final int    COLUMN_SELECTED_idx = 3;
  28.  
  29.     public sqliteDatabase dbsqlite;
  30.     private Context mContext;
  31.  
  32.     public sqlHelper(Context context) {
  33.         super(context,DATABASE_NAME,null,1);
  34.         mContext = context;
  35.     }
  36.  
  37.     @Override
  38.     public void onCreate(sqliteDatabase db) {
  39.         createDB(db);
  40.     }
  41.  
  42.     @Override
  43.     public void onUpgrade(sqliteDatabase db,int oldVersion,int newVersion) {
  44.         Log.w("sqlHelper","Upgrading database from version " + oldVersion
  45.                 + " to " + newVersion + ",which will destroy all old data");
  46.  
  47.         db.execsql("DROP TABLE IF EXISTS ToDoItems;");
  48.  
  49.         createDB(db);
  50.     }
  51.  
  52.     public void createDatabase(sqliteDatabase db) {
  53.         createDB(db);
  54.     }
  55.  
  56.     private void createDB(sqliteDatabase db) {
  57.         if (db == null) {
  58.             db = mContext.openOrCreateDatabase(DATABASE_NAME,null);
  59.         }
  60.  
  61.         db.execsql("CREATE TABLE IF NOT EXISTS ToDoItems (_id INTEGER PRIMARY KEY,title TEXT,"
  62.                 +" description TEXT,selected INTEGER);");
  63.         db.setVersion(ToDoItems_VERSION);
  64.  
  65.         //
  66.         // Generate a few rows for an example
  67.         //
  68.         // find out how many rows already exist,and make sure there's some minimum
  69.         sqliteStatement s = db.compileStatement("select count(*) from ToDoItems;");
  70.  
  71.         long count = s.simpleQueryForLong();
  72.         for (int i = 0; i < 20-count; i++) {
  73.             db.execsql("INSERT INTO ToDoItems VALUES(NULL,'Task #"+i+"','Description #"+i+"',0);");
  74.         }
  75.     }
  76.  
  77.     public void openDataBase() throws sqlException {
  78.         String myPath = DATABASE_PATH + DATABASE_NAME;
  79.  
  80.         dbsqlite = sqliteDatabase.openDatabase(myPath,sqliteDatabase.OPEN_READWRITE);
  81.     }
  82.  
  83.     @Override
  84.     public synchronized void close() {
  85.         if (dbsqlite != null)
  86.             dbsqlite.close();
  87.  
  88.         super.close();
  89.     }
  90.  
  91.     public Cursor getCursor() {
  92.         sqliteQueryBuilder queryBuilder = new sqliteQueryBuilder();
  93.  
  94.         queryBuilder.setTables(TABLE_NAME);
  95.  
  96.         String[] asColumnsToReturn = new String[] { COLUMN_ID,COLUMN_TITLE,COLUMN_NAME_DESC,COLUMN_SELECTED };
  97.  
  98.         Cursor mCursor = queryBuilder.query(dbsqlite,asColumnsToReturn,COLUMN_ID+" ASC");
  99.  
  100.         return mCursor;
  101.     }
  102.  
  103.     public void clearSelections() {
  104.         ContentValues values = new ContentValues();
  105.         values.put(COLUMN_SELECTED,0);
  106.         this.dbsqlite.update(sqlHelper.TABLE_NAME,null);
  107.     }
  108. }

Start.java

  1. //src/Start.java
  2. package com.appfulcrum.blog.examples.listviewcustomdb;
  3.  
  4. import android.app.Activity;
  5. import android.content.Intent;
  6. import android.os.Bundle;
  7. import android.view.View;
  8. import android.view.View.OnClickListener;
  9. import android.widget.Button;
  10. import android.widget.Toast;
  11.  
  12. public class Start extends Activity {
  13.     /** Called when the activity is first created. */
  14.     @Override
  15.     public void onCreate(Bundle savedInstanceState) {
  16.         super.onCreate(savedInstanceState);
  17.         setContentView(R.layout.main);
  18.  
  19.         Button btnSimple = (Button) findViewById(R.id.btnSimple);
  20.         btnSimple.setOnClickListener(new OnClickListener() {
  21.  
  22.             public void onClick(View v) {
  23.  
  24.                 Toast.makeText(getApplicationContext()," You clicked ListView From DB button",Toast.LENGTH_SHORT).show();
  25.  
  26.                 Intent intent = new Intent(v.getContext(),CustomListViewDB.class);
  27.                 startActivityForResult(intent,0);
  28.             }
  29.         });
  30.  
  31.     }
  32. }

布局/ main.xml中

  1. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.     android:id="@+id/buttonlayout" android:orientation="vertical"
  3.     android:layout_width="fill_parent" android:layout_height="fill_parent"
  4.     android:gravity="left|top" android:paddingTop="2dp"
  5.     android:paddingBottom="2dp">
  6.  
  7.     <TextView android:id="@+id/txtTest" android:layout_width="fill_parent"
  8.         android:layout_height="wrap_content" android:textStyle="bold"
  9.         android:text="@string/app_name" android:textSize="15sp"
  10.         android:textColor="#FF0000" android:gravity="center_vertical"
  11.         android:paddingLeft="5dp">
  12.     </TextView>
  13.  
  14.     <Button android:id="@+id/btnSimple" 
  15.         android:layout_width="fill_parent"
  16.         android:layout_height="wrap_content" 
  17.         android:textSize="15sp"
  18.         android:text="Listview from DB"
  19.         android:textColor="#000000"
  20.         >
  21.     </Button>
  22.  
  23. </LinearLayout>

布局/ simple.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     android:orientation="vertical" android:layout_width="fill_parent"
  4.     android:layout_height="fill_parent">
  5.  
  6.     <LinearLayout android:id="@+id/buttonlayout"
  7.         android:orientation="horizontal" android:layout_width="fill_parent"
  8.         android:layout_height="wrap_content" android:height="32dp"
  9.         android:gravity="left|top" android:paddingTop="2dp"
  10.         android:paddingBottom="2dp">
  11.  
  12.         <LinearLayout android:id="@+id/buttonlayout2"
  13.             android:orientation="horizontal" android:layout_height="wrap_content"
  14.             android:gravity="left|center_vertical" android:layout_width="wrap_content"
  15.             android:layout_gravity="left|center_vertical">
  16.  
  17.             <TextView android:id="@+id/txtTest"
  18.                 android:layout_width="fill_parent"
  19.                 android:layout_height="fill_parent" android:textStyle="bold"
  20.                 android:text="@string/list_header" android:textSize="15sp"
  21.                 android:gravity="center_vertical" android:paddingLeft="5dp">
  22.             </TextView>
  23.  
  24.             <Button android:id="@+id/btnClear"
  25.                 android:layout_width="wrap_content"
  26.                 android:layout_height="wrap_content" android:text="Clear"
  27.                 android:textSize="15sp" android:layout_marginLeft="10px"
  28.                 android:layout_marginRight="10px"
  29.                 android:layout_marginBottom="2px"
  30.                 android:layout_marginTop="2px" android:height="15dp"
  31.                 android:width="70dp"></Button>
  32.         </LinearLayout>
  33.     </LinearLayout>
  34.  
  35.     <TableLayout android:id="@+id/TableLayout01"
  36.         android:layout_width="fill_parent" android:layout_height="fill_parent"
  37.         android:stretchColumns="*">
  38.         <TableRow>
  39.             <ListView android:id="@android:id/list"
  40.                 android:layout_width="wrap_content"
  41.                 android:layout_height="wrap_content"></ListView>
  42.         </TableRow>
  43.  
  44.     </TableLayout>
  45.  
  46. </LinearLayout>

布局/ single_item.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     android:layout_width="fill_parent" android:layout_height="wrap_content"
  4.     android:orientation="horizontal" android:gravity="center_vertical">
  5.  
  6.     <CheckBox android:id="@+id/bcheck"
  7.               android:layout_width="wrap_content"
  8.               android:layout_height="fill_parent" />
  9.  
  10.         <TextView android:id="@+id/txtTitle"
  11.             android:layout_width="wrap_content" android:gravity="left|center_vertical"
  12.             android:layout_height="?android:attr/listPreferredItemHeight"
  13.             android:layout_alignParentLeft="true" 
  14.             android:textSize="20sp" android:text="Test"
  15.             android:textStyle="bold" android:paddingLeft="5dp"
  16.             android:paddingRight="2dp" android:focusable="false"
  17.             android:focusableInTouchMode="false"></TextView>
  18.         <LinearLayout android:layout_width="fill_parent"
  19.             android:layout_height="wrap_content" android:orientation="horizontal"
  20.             android:gravity="right|center_vertical">
  21.         </LinearLayout>
  22.  
  23. </LinearLayout>

值/ strings.xml中

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <resources>
  3.     <string name="hello">Hello World,ListViewWithDBActivity!</string>
  4.     <string name="app_name">ListViewWithDB</string>
  5.     <string name="list_header">List Headers</string>
  6. </resources>

AndroidManifest.xml中

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
  3.     android:versionCode="1" android:versionName="1.0"    
  4.     package="com.appfulcrum.blog.examples.listviewcustomdb">
  5.  
  6.     <application android:icon="@drawable/icon"
  7.         android:label="@string/app_name" 
  8.         android:theme="@android:style/Theme.NoTitleBar">
  9.         >
  10.         <activity android:name=".Start" android:label="@string/app_name">
  11.             <intent-filter>
  12.                 <action android:name="android.intent.action.MAIN" />
  13.                 <category android:name="android.intent.category.LAUNCHER" />
  14.             </intent-filter>
  15.         </activity>
  16.         <activity android:name=".CustomListViewDB"></activity>
  17.     </application>
  18.  
  19.     <uses-sdk android:minSdkVersion="7" /> <!-- android 1.6 -->
  20. </manifest>

如果你想构建,将一些任意的icon.png扔进drawable.

提前致谢.

解决方法

我发现异地问题最完整的解决方案.

在Android ListView with CheckBox : Retain State

感谢帮助人员.

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