如何在textview中显示数据库查询？

我必须为大学项目制作一个Hangman应用程序，此刻我创建了一个SQLite数据库，并在其中放了几个字。我试图运行一个查询来选择一个随机的单词并将其显示在textview中，但是我无法获得显示的结果。如何在textview中显示数据库查询？

这是我迄今为止

import android.os.Bundle; 
import android.app.Activity; 
import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.util.Log; 
import android.view.Menu; 
import android.widget.Button; 
import android.widget.TextView; 

class Hangman extends Activity { 

public TextView wordText; 
public Button button02A; 
private Button button01B; 
private Button button03C; 
private Button button04D; 
private Button button05E; 
private Button button06F; 
private Button button07G; 
private Button button1H; 
private Button button09I; 
private Button button10J; 
private Button button11K; 
private Button button12L; 
private Button button13M; 
private Button button14N; 
private Button button15O; 
private Button button16P; 
private Button button18Q; 
private Button button19R; 
private Button button20S; 
private Button button21T; 
private Button button17U; 
private Button button22V; 
private Button button23W; 
private Button button08X; 
private Button button25Y; 
private Button button26Z; 
private Button button24Voice; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_hangman); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.activity_hangman, menu); 
    return true; 
} 

public void assignButtons() { 

    wordText = (TextView) findViewById(R.id.wordText); 
    button02A = (Button) findViewById(R.id.Button02); 
    button01B = (Button) findViewById(R.id.Button01); 
    button03C = (Button) findViewById(R.id.Button03); 
    button04D = (Button) findViewById(R.id.Button04); 
    button05E = (Button) findViewById(R.id.Button05); 
    button06F = (Button) findViewById(R.id.Button06); 
    button07G = (Button) findViewById(R.id.Button07); 
    button1H = (Button) findViewById(R.id.button1); 
    button09I = (Button) findViewById(R.id.Button09); 
    button10J = (Button) findViewById(R.id.Button10); 
    button11K = (Button) findViewById(R.id.Button11); 
    button12L = (Button) findViewById(R.id.Button12); 
    button13M = (Button) findViewById(R.id.Button13); 
    button14N = (Button) findViewById(R.id.Button14); 
    button15O = (Button) findViewById(R.id.Button15); 
    button16P = (Button) findViewById(R.id.Button16); 
    button18Q = (Button) findViewById(R.id.Button18); 
    button19R = (Button) findViewById(R.id.Button19); 
    button20S = (Button) findViewById(R.id.Button20); 
    button21T = (Button) findViewById(R.id.Button21); 
    button17U = (Button) findViewById(R.id.Button17); 
    button22V = (Button) findViewById(R.id.Button22); 
    button23W = (Button) findViewById(R.id.Button23); 
    button08X = (Button) findViewById(R.id.Button08); 
    button25Y = (Button) findViewById(R.id.Button25); 
    button26Z = (Button) findViewById(R.id.Button26); 
    button24Voice = (Button) findViewById(R.id.Button24); 
} 

} 

class NewDatabase extends SQLiteOpenHelper { 

//Create Database 
private static final String DATABASE_NAME = "myDatabase.db"; 
private static final String DATABASE_TABLE ="Puzzles"; 
public static final String COLUMN_PUZZLES = "Puzzlescol"; 
public static final String COLUMN_ID = "_id"; 
private static final int DATABASE_VERSION = 1; 

private static final String DATABASE_CREATE = "create table " 
      + DATABASE_TABLE + "(" + COLUMN_ID 
      + " integer primary key autoincrement, " + COLUMN_PUZZLES 
      + " text not null);"; 


public NewDatabase(Context context, String name, 
CursorFactory factory, int version) { 
super(context, name, factory, version); 
} 
//Overriding onCreate and onUpgrade to create database 
    @Override 
    public void onCreate(SQLiteDatabase database) { 
    database.execSQL(DATABASE_CREATE); 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    Log.w(NewDatabase.class.getName(), 
     "Upgrading database from version " + oldVersion + " to " 
      + newVersion + ", which will destroy all old data"); 
    db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE); 
    onCreate(db); 
    } 

public void insertRows(){ 
    ContentValues values = new ContentValues(); 

    values.put(COLUMN_ID, "1"); 
    values.put(COLUMN_PUZZLES, "MERMAID"); 
    values.put(COLUMN_ID, "2"); 
    values.put(COLUMN_PUZZLES, "SUITCASE"); 
    values.put(COLUMN_ID, "3"); 
    values.put(COLUMN_PUZZLES, "OSTRICH"); 

    } 

public String randWord() { 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor cur = db.query("DATABASE_TABLE Order BY RANDOM() LIMIT 1", 
    new String[] { "*" }, null, null, null, null, null); 

     return cur.getString(cur.getColumnIndex(COLUMN_PUZZLES)); 
} 

public void showWord(Cursor cur) { 
    wordText.setText(cur); 

} 
}

来源

2012-12-19 Pedroson

。首先设置一个点击监听器到任何按钮，创建一个NewDatabase类的实例来插入或从数据库中选择值。你也可以看到[this]（http://www.androidhive.info/2011/11/android-sqlite-database -tutorial /）教程 –

你有什么样的麻烦？ –

谢谢我会看看这个教程。 – Pedroson

创建自己的应用Hungman。创建基本DBHelper。添加一些词来测试。设置hang子手逻辑。

它更好地动态创建UI元素。为新元素创建布局作为方框，但以编程方式将其放在那里。

private LinearLayout lettersLayout; 
private final String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; *** 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_hangman); 
lettersLayout = (LinearLayout) findViewById(R.id.lettersLay); ** 
for (String alphabetLetter : alphabet.split("(?!^)")) { 
TextView alphabetLetterTxt = new TextView(this); 
alphabetLetterTxt.setText(alphabetLetter); 
lettersLayout.addView(alphabetLetter); 
}

这里是SQLitte数据库工作的简单例子：

刚才创建NewDatabase类通过扩展SQLiteOpenHelper但在应用程序中不使用

public class DBHelper extends SQLiteOpenHelper { 

private static DBHelper instance; 
private static final String DATABASE_NAME = "HangmanBase"; 
    private static final int DATABASE_VERSION = 5; 
public static interface WORD extends BaseColumns { 
     String TABLE_NAME = "wordTable"; 
     String WORD = "word"; 
     String DESCRIPTION = "wordDescription"; 
    } 
private static final String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS "; 
    private static final String DROP_TABLE = "DROP TABLE IF EXISTS "; 
    private static final String UNIQUE = "UNIQUE ON CONFLICT ABORT"; 
private static final String CREATE_TABLE_WORD = CREATE_TABLE + WORD.TABLE_NAME + " (" + WORD._ID 
      + " INTEGER PRIMARY KEY, " + WORD.WORD + " TEXT " + UNIQUE + ", " + WORD.DESCRIPTION + " TEXT);"; 
private DBHelper(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 
public static DBHelper getInstance(Context context) { 
     if (instance == null) { 
      instance = new DBHelper(context); 
     } 
     return instance; 
    } 
@Override 
    public void onCreate(SQLiteDatabase db) { 
     db.execSQL(CREATE_TABLE_WORD); 
    } 
@Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     db.execSQL(DROP_TABLE + WORD.TABLE_NAME); 
     onCreate(db); 
    } 
public long addWord(String newWord, String newWordDescription) { 
     ContentValues values = new ContentValues(); 
     values.put(WORD.WORD.toUpperCase(Locale.UK), newWord); 
     values.put(WORD.DESCRIPTION, newWordDescription); 
     return getWritableDatabase().insert(WORD.TABLE_NAME, null, values); 
    } 
public HangmanWord getRandomWord() { 
     Cursor allWordsList = getReadableDatabase().rawQuery("SELECT * FROM " + WORD.TABLE_NAME, null); 
     if (allWordsList != null && allWordsList.getCount() > 0) { 
      Random random = new Random(); 
      allWordsList.moveToPosition(random.nextInt(allWordsList.getCount())); 
      return new HangmanWord(allWordsList.getString(allWordsList.getColumnIndex(WORD.WORD)), 
        allWordsList.getString(allWordsList.getColumnIndex(WORD.DESCRIPTION))); 
     } 
     return null; 
    } 
}

来源

2013-11-04 07:24:45 QArea

如何在textview中显示数据库查询？

回答

相关问题