[Android]_ch8.4_讀取外部資料庫

public ArrayList<String> queryDB(Context context){

SQLiteDatabase db=context.openOrCreateDatabase("NCTU.db", Context.MODE_WORLD_WRITEABLE, null);

String args[]={"Taipei","Hsinchu"};

Cursor cursor=db.rawQuery("SELECT * FROM student WHERE address=?;", args);

ArrayList<String> list=new ArrayList<String>();

StringBuilder sb=new StringBuilder("查詢筆數:"+cursor.getCount()+"筆"+"\n欄位:"+cursor.getColumnCount()+"欄\n");

while(cursor.moveToNext()){

sb.append(cursor.getString(0)+"\t");

sb.append(cursor.getString(1)+"\t");

sb.append(cursor.getString(2)+"\t");

sb.append(cursor.getString(3)+"\n");

}

list.add(sb.toString());

return list;

}

btn4.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

ArrayList<String> list=dbhp.queryDB(MainActivity.this);

if(list.size()>0){

tv1.setText(list.get(0));

}else{

tv1.setText("查詢不到資料...");

}

}

});