SQLite數據庫信息的結構到ListView

我在這裏看到了一些答案，但是很多答案要麼超過我的頭，要麼我無法將它們與我的應用程序相關聯。我想知道是否有人可以爲我分解一點，因爲我對編程很陌生。SQLite數據庫信息的結構到ListView

我想用Android中的SQLite數據庫中的數據填充ExpandableListView。我有一個名爲DatabaseHelper的類，它創建數據庫/表並添加和刪除數據，我甚至可以通過Cursor調用信息以在AlertDialog中顯示數據。不過，我試圖將這些信息動態加載到ExpandableListView中。

我在數據庫幫助這個方法：

public Cursor getAllData() { 
    SQLiteDatabase db = this.getWritableDatabase(); 
    Cursor res = db.rawQuery("SELECT * FROM "+ TABLE_NAME, null); 
    return res;

它返回一個Cursor對象與表裏面。然而，然後填充ListView我的理解是，我需要使用SimpleCursorAdapter，並將其應用於ListView。我是否需要爲SimpleCursorAdapter創建一個獨立的類？如果是這樣的話，我怎樣才能將SimpleCursorAdaptor應用到我的expandableListView？

我所有的代碼如下。

MainActivity.java

public class MainActivity extends AppCompatActivity { 

DatabaseHelper myDb; 
EditText editName, editSurname, editAge; 
Button btnAddData, btnViewAll; 
ListView listView; 
private SimpleCursorAdapter dataAdapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    myDb = new DatabaseHelper(this); 
    Cursor c = myDb.getReadableDatabase().rawQuery("SELECT * FROM " + DatabaseHelper.TABLE_NAME, null); 



    editName = (EditText) findViewById(R.id.editText_Name); 
    editSurname = (EditText) findViewById(R.id.editText_Surname); 
    editAge = (EditText) findViewById(R.id.editText_Age); 
    btnAddData = (Button) findViewById(R.id.button_add); 
    btnViewAll = (Button) findViewById(R.id.button_viewAll); 
    listView = (ListView) findViewById(R.id.expandableListView); 






    displayListView(); 
    AddData(); 
    viewAll(); 
} 

private void displayListView() { 

    Cursor cursor = myDb.getAllData(); 

    String[] columns = new String[] { 
     DatabaseHelper.COL1, 
     DatabaseHelper.COL2, 
     DatabaseHelper.COL3, 
     DatabaseHelper.COL4 
    }; 

    int[] to = new int[] { 
     R.id.textView2, 
     R.id.textView4, 
     R.id.textView6, 
    }; 

    dataAdapter = new SimpleCursorAdapter(
      this, R.layout.listlayout, 
      cursor, 
      columns, 
      to, 
      0); 


    listView.setAdapter(dataAdapter); 


} 

public void viewAll() { 
    btnViewAll.setOnClickListener(
      new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        Cursor res = myDb.getAllData(); 
        if (res.getCount() == 0) { 
         // show message (no data in table) 
         showMessage("Error", "No Data Found"); 
         return; 
        } 

        StringBuffer buffer = new StringBuffer(); 
        while (res.moveToNext()) { 
         buffer.append("ID: "+ res.getString(0) + "\n"); 
         buffer.append("Name: "+ res.getString(1) + "\n"); 
         buffer.append("Surname: "+ res.getString(2) + "\n"); 
         buffer.append("Age: "+ res.getString(3) + "\n"); 
        } 

        showMessage("Data", buffer.toString()); 

       } 
      } 
    ); 
} 




public void showMessage(String title, String message){ 
    AlertDialog.Builder builder = new AlertDialog.Builder(this); 
    builder.setCancelable(true); 
    builder.setTitle(title); 
    builder.setMessage(message); 
    builder.show(); 

} 

public void AddData() { 
    btnAddData.setOnClickListener(
      new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        Boolean isInserted = myDb.insertData(editName.getText().toString(), 
          editSurname.getText().toString(), 
          editAge.getText().toString()); 

        if(isInserted = true) { 
         Toast.makeText(MainActivity.this, "Data Inserted", Toast.LENGTH_SHORT).show(); 
        } else { 
         Toast.makeText(MainActivity.this, "Data is not Inserted", Toast.LENGTH_SHORT).show(); 
        } 
       } 
      } 
    ); 
}

}

DatabaseHelper.java

public class DatabaseHelper extends SQLiteOpenHelper{ 

public static final String DATABASE_NAME = "People.db"; 
public static final String TABLE_NAME = "people_table"; 
public static final String COL1 = "ID"; 
public static final String COL2 = "NAME"; 
public static final String COL3 = "SURNAME"; 
public static final String COL4 = "AGE"; 



public DatabaseHelper(Context context) { 
    super(context, DATABASE_NAME, null, 1); 

} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    db.execSQL("CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,SURNAME TEXT,AGE INTEGER)"); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); 
    onCreate(db); 
} 

public boolean insertData(String name, String surname, String age) { 
    SQLiteDatabase db = this.getWritableDatabase(); 
    ContentValues contentValues = new ContentValues(); 
    contentValues.put(COL2, name); 
    contentValues.put(COL3, surname); 
    contentValues.put(COL4, age); 
    long result = db.insert(TABLE_NAME, null, contentValues); 
    if (result == -1) 
     return false; 
    else 
     return true; 

} 

public Cursor getAllData() { 
    SQLiteDatabase db = this.getWritableDatabase(); 
    Cursor res = db.rawQuery("SELECT * FROM "+ TABLE_NAME, null); 
    return res; 
} 
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
tools:context="com.welcometech.database.MainActivity"> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Name" 
    android:id="@+id/textView" 
    android:layout_alignParentTop="true" 
    android:layout_toLeftOf="@+id/editText_Name" 
    android:layout_toStartOf="@+id/editText_Name" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Surname" 
    android:id="@+id/textView2" 
    android:layout_below="@+id/textView" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_marginTop="44dp" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Age" 
    android:id="@+id/textView3" 
    android:layout_marginTop="37dp" 
    android:layout_below="@+id/textView2" 
    android:layout_toLeftOf="@+id/editText_Age" 
    android:layout_toStartOf="@+id/editText_Age" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Name" 
    android:layout_alignTop="@+id/textView" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Surname" 
    android:layout_above="@+id/textView3" 
    android:layout_alignRight="@+id/editText_Name" 
    android:layout_alignEnd="@+id/editText_Name" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Age" 
    android:layout_alignBottom="@+id/textView3" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<Button 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Add Data" 
    android:id="@+id/button_add" 
    android:layout_centerVertical="true" 
    android:layout_below="@+id/textView3" 
    android:layout_marginTop="20dp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" /> 

<Button 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="View All" 
    android:id="@+id/button_viewAll" 
    android:layout_alignTop="@+id/button_add" 
    android:layout_toRightOf="@+id/button_add" 
    android:layout_toEndOf="@+id/button_add" /> 

<ExpandableListView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/expandableListView" 
    android:layout_alignParentBottom="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_below="@+id/button_add" /> 
</RelativeLayout>

listlayout.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_horizontal_margin" 
android:paddingRight="@dimen/activity_horizontal_margin" 
android:paddingTop="@dimen/activity_vertical_margin" 
tools:context="com.welcometech.database.MainActivity"> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Name" 
    android:id="@+id/textView" 
    android:layout_alignParentTop="true" 
    android:layout_toLeftOf="@+id/editText_Name" 
    android:layout_toStartOf="@+id/editText_Name" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Surname" 
    android:id="@+id/textView2" 
    android:layout_below="@+id/textView" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_marginTop="44dp" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Age" 
    android:id="@+id/textView3" 
    android:layout_marginTop="37dp" 
    android:layout_below="@+id/textView2" 
    android:layout_toLeftOf="@+id/editText_Age" 
    android:layout_toStartOf="@+id/editText_Age" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Name" 
    android:layout_alignTop="@+id/textView" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Surname" 
    android:layout_above="@+id/textView3" 
    android:layout_alignRight="@+id/editText_Name" 
    android:layout_alignEnd="@+id/editText_Name" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<EditText 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/editText_Age" 
    android:layout_alignBottom="@+id/textView3" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" 
    android:layout_toRightOf="@+id/textView2" 
    android:layout_toEndOf="@+id/textView2" /> 

<Button 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Add Data" 
    android:id="@+id/button_add" 
    android:layout_centerVertical="true" 
    android:layout_below="@+id/textView3" 
    android:layout_marginTop="20dp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" /> 

<Button 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="View All" 
    android:id="@+id/button_viewAll" 
    android:layout_alignTop="@+id/button_add" 
    android:layout_toRightOf="@+id/button_add" 
    android:layout_toEndOf="@+id/button_add" /> 

<ExpandableListView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/expandableListView" 
    android:layout_alignParentBottom="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_below="@+id/button_add" /> 
</RelativeLayout>

來源

2016-04-25 Chris Wakeling

您需要創建一個適配器。在你需要傳遞

ArrayList <HashMap<String,String>>

你getAllData（）方法應該是這樣的：

public ArrayList<HashMap<String,String>> getAllData(){ 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>(); 
     HashMap<String,String> hashmap; 

     String query_select = "SELECT column1, column2 FROM tablename ; 

     Cursor cursor = db.rawQuery(query_select,null); 
     if (cursor.moveToFirst()) { 
      do { 
       hashMap = new HashMap<String,String>(); 
       hashMap.put("column1", cursor.getString(0)); 
       hashMap.put("column2",cursor.getString(1)); 
       list.add(hashmap); 
      } while (cursor.moveToNext()); 
     } 
     cursor.close(); 

     return list; 
    }

此方法將返回ArrayList中，你需要將其設置爲您的適配器，然後設置你的適配器到您的ListView。

來源

2016-04-25 04:20:31 KishuDroid

SQLite數據庫信息的結構到ListView

回答

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