ListView 和 SQLite on SD Help

Question

我创建了一个硬编码的listView，现在我想将其更改为从sd卡上的dB填充。

我创建了一个SQLHelper(从这里借用)，其中包含底部的光标，我修改它为getExternalStorageState和getExternalStorageDirectory来设置我的dB路径。

我读了几个关于这个主题的教程，但现在我迷路了，不知道如何修改我现有的类来使用SQLHelper来获得listView来填充。任何帮助、建议或片段都将非常感激，我希望这篇文章能帮助到任何一个自己编码的人非常感谢!

SQLHelper.java我需要实现:

public class AC_SqlHelper extends SQLiteOpenHelper 
{
static String extStorageDirectory;
public void sdState()
{
    if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
    {
        extStorageDirectory = Environment.getExternalStorageDirectory().toString();
    }
    else
    {
        //TODO
    }
} 
public static final String DATABASE_PATH = (extStorageDirectory  + "/Folder/Folder/dB/");
public static final String DATABASE_NAME = "myAppDB";
public static final String TABLE_NAME = "aTable";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_LABEL = "label";
public static final String COLUMN_TITLE = "title";
public static final String COLUMN_CAPTION = "caption";
public static final String COLUMN_URL = "url";
public SQLiteDatabase dbSqlite;
private final Context myContext;
public AC_SqlHelper(Context context) 
{
    super(context, DATABASE_NAME, null, 1);
    this.myContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) 
{
    // check if exists and copy database from resource
    createDB();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
{
    Log.w("SqlHelper", "Upgrading database from version " + oldVersion
            + " to " + newVersion + ", which will destroy all old data");
    onCreate(db);
}
public void createDatabase() 
{
    createDB();
}
private void createDB() 
{
    boolean dbExist = DBExists();
    if (!dbExist) 
    {
        copyDBFromResource();
    }
}
private boolean DBExists() 
{
    SQLiteDatabase db = null;
    try {
        String databasePath = DATABASE_PATH + DATABASE_NAME;
        db = SQLiteDatabase.openDatabase(databasePath, null,
                SQLiteDatabase.OPEN_READWRITE);
        db.setLocale(Locale.getDefault());
        db.setLockingEnabled(true);
        db.setVersion(1);
    } catch (SQLiteException e) 
    {
        Log.e("SqlHelper", "database not found");
    }
    if (db != null) 
    {
        db.close();
    }
    return db != null ? true : false;
}
private void copyDBFromResource() 
{
    InputStream inputStream = null;
    OutputStream outStream = null;
    String dbFilePath = DATABASE_PATH + DATABASE_NAME;
    try 
    {
        inputStream = myContext.getAssets().open(DATABASE_NAME);
        outStream = new FileOutputStream(dbFilePath);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) 
        {
            outStream.write(buffer, 0, length);
        }
        outStream.flush();
        outStream.close();
        inputStream.close();
    } 
    catch (IOException e) 
    {
        throw new Error("Problem copying database from resource file.");
    }
}
public void openDataBase() throws SQLException 
{
    String myPath = DATABASE_PATH + DATABASE_NAME;
    dbSqlite = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() 
{
    if (dbSqlite != null)
        dbSqlite.close();
    super.close();
}
public Cursor getCursor() 
{
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    queryBuilder.setTables(TABLE_NAME);
    String[] asColumnsToReturn = new String[] { COLUMN_ID, COLUMN_LABEL,
            COLUMN_TITLE, COLUMN_CAPTION, COLUMN_URL };
    Cursor mCursor = queryBuilder.query(dbSqlite, asColumnsToReturn, null,
            null, null, null, "title ASC");
    return mCursor;
}
}

这是我当前的列表活动(AC_List.java):

public class List_AC extends Activity 
{
protected TextView activityTitle;
@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.list_view);
    activityTitle = (TextView) findViewById(R.id.titleBarTitle);
    activityTitle.setText("ADVISORY CIRCULATORS");
    ArrayList<SearchResult> searchResults = GetSearchResults();
    final ListView lv1 = (ListView) findViewById(R.id.listItems);
    lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults));
    lv1.setOnItemClickListener(new OnItemClickListener() 
    {
         public void onItemClick(AdapterView<?> a, View v, int position, long id) 
         { 
              Object o = lv1.getItemAtPosition(position);
              SearchResult fullObject = (SearchResult)o;
              Toast.makeText(List_AC.this, "You have chosen: " + " " + fullObject.getListTitle(), Toast.LENGTH_LONG).show();
              Intent i = new Intent(List_AC.this, View_ACdoc.class);
              i.putExtra("url", fullObject.getURL());
              startActivity(i);
         }  
    });
private ArrayList<SearchResult> GetSearchResults()
{
 ArrayList<SearchResult> results = new ArrayList<SearchResult>();
     SearchResult sr1 = new SearchResult();
     sr1.setLabel("A Label");
     sr1.setListTitle("The Title");
     sr1.setCaption("Some captions.");
     sr1.setURL("http://www.mysite/index.html");
     results.add(sr1);
     return results;
}
}

…下面是我目前支持的类:

MyCustomBaseAdapter.java:

public class MyCustomBaseAdapter extends BaseAdapter {
 private static ArrayList<SearchResult> searchArrayList;
 private LayoutInflater mInflater;
 public MyCustomBaseAdapter(Context context, ArrayList<SearchResult> results) {
  searchArrayList = results;
  mInflater = LayoutInflater.from(context);
 }
 public int getCount() {
  return searchArrayList.size();
 }
 public Object getItem(int position) {
  return searchArrayList.get(position);
 }
 public long getItemId(int position) {
  return position;
 }
 public View getView(int position, View convertView, ViewGroup parent) {
  ViewHolder holder;
  if (convertView == null) {
   convertView = mInflater.inflate(R.layout.list_item, null);
   holder = new ViewHolder();
   holder.txtLabel = (TextView) convertView.findViewById(R.id.label);
   holder.txtListTitle = (TextView) convertView.findViewById(R.id.listTitle);
   holder.txtCaption = (TextView) convertView.findViewById(R.id.caption);
   convertView.setTag(holder);
  } else {
   holder = (ViewHolder) convertView.getTag();
  }
  holder.txtLabel.setText(searchArrayList.get(position).getLabel());
  holder.txtListTitle.setText(searchArrayList.get(position).getListTitle());
  holder.txtCaption.setText(searchArrayList.get(position).getCaption());
  return convertView;
 }
 static class ViewHolder {
  TextView txtLabel;
  TextView txtListTitle;
  TextView txtCaption;
 }
}

SearchResult.java:

public class SearchResult 
{
     private String label = "";
 private String listTitle = "";
 private String caption = "";
 private String listURL = "";
 private String listActivity = "";
 public void setLabel(String label) {
  this.label = label;
 }
 public String getLabel() {
  return label;
 }
 public void setListTitle(String listTitle) {
  this.listTitle = listTitle;
 }
 public String getListTitle() {
  return listTitle;
 }
 public void setCaption(String caption) {
  this.caption = caption;
 }
 public String getCaption() {
  return caption;
 }
//   
 public void setURL(String listURL) {
      this.listURL = listURL;
     }
     public String getURL() {
      return listURL;
     }
public void setActivity(String listActivity) {
    this.listActivity = listActivity;
    }
    public String getActivity() {
    return listActivity;
    } 
}

Answer 1

最简单的方法是使用SimpleCursorAdapter;