我需要更新数据库中的选定列,但是我无法获取更新的数据。用户单击下一步按钮后,数据应该会更新。表中总共需要更新 12 个字段。
场景有点不同,我已经有一个活动,主要说是否插入了 5 个字段,而在第二个活动中,我需要更新 SAME TABLE 中的 5 个字段
提前致谢
注意:dba 是 DBAdapter,即数据库,myDB 是 SQLiteDatabase
nxt = (Button)findViewById(R.id.btn_nxt);
nxt.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
String b1=t1.getText().toString();
String b2=goal_website_trying_to_achieve_edttxt.getText().toString();
String b3=communicate_edttxt.getText().toString();
String b4=success_look_like_edttxt.getText().toString();
String b5=usp_insights_edttxt.getText().toString();
String b6=act_edttxt.getText().toString();
String b7=market_edttxt.getText().toString();
String b8=your_current_website_www_edttxt.getText().toString();
String b9=your_current_website_good_edttxt.getText().toString();
String b10=your_current_website_bad_edttxt.getText().toString();
String b11=your_current_website_type_edttxt.getText().toString();
String b12=your_current_website_update_edttxt.getText().toString();
String b13=your_current_website_supporting_edttxt.getText().toString();
if(!validatescreen2()){
return;
}
else{
myDB = DBAdapter.openDatabase(Newform_Screen2.this,DBAdapter.DATABASE_TABLE);
String updatequery = "UPDATE"+ DBAdapter.DATABASE_TABLE+ " SET ";
updatequery = updatequery + " KEY_MESSAGE_1 = '" + b1 + "',";
updatequery = updatequery + " KEY_MESSAGE_2 = '" + b2 + "',";
updatequery = updatequery + " KEY_MESSAGE_3 = '" + b3 + "',";
updatequery = updatequery + " KEY_MESSAGE_4 = '" + b4 + "',";
updatequery = updatequery + " KEY_MESSAGE_5 = '" + b5 + "',";
updatequery = updatequery + " KEY_MESSAGE_6 = '" + b6 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_1 = '" + b7 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_2 = '" + b8 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_3 = '" + b9 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_TYPE = '" + b10 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_NEED = '" + b11 + "',";
updatequery = updatequery + " KEY_YOUR_CURRENT_WEBSITE_OTHER = '" + b12 + ",";
updatequery = updatequery + "WHERE" + DBAdapter.KEY_ROWID + "=" + mRowId +"';";
try{
myDB.execSQL(updatequery);
}catch(Exception e){
//Log("Caught while writing response" + e.getLocalizedMessage());
}finally{
if(myDB != null)myDB.close();
showDialog(DIALOG_ID);
}
}
}
});
在DBAdapter
课堂上
public static SQLiteDatabase openDatabase(Context context, String DBname){
SQLiteDatabase myDB;
myDB = context.openOrCreateDatabase(DBname,Context.MODE_PRIVATE, null);
Cursor rs = null;
boolean tableExists;
try{
rs = myDB.rawQuery("SELECT * FROM " + DATABASE_TABLE + " WHERE 1=0", null );
tableExists = true;
}catch(Exception ex){
tableExists = false;
}finally{
if (rs != null) rs.close();
}
if(!tableExists) {
myDB.execSQL(DATABASE_CREATE);
}
return myDB;
}
public static void executeQuery(SQLiteDatabase db,String query){
if(db != null){
db.execSQL(query);
}
}
public static Cursor selectQuery(SQLiteDatabase db,String query){
if(db != null)
{
Cursor c = db.rawQuery(query,null);
return c;
}
else
return null;
}
public static void closeDatabase(SQLiteDatabase db){
if (db != null)
{
//Log("Closing Database conn");
db.close();
}
}
进行更改后,但仍然无法更新..我需要进行任何其他更改吗?
dba.open();
ContentValues args = new ContentValues();
args.put(DBAdapter.KEY_MESSAGE_1, b2);
args.put(DBAdapter.KEY_MESSAGE_2, b3);
args.put(DBAdapter.KEY_MESSAGE_3, b4);
args.put(DBAdapter.KEY_MESSAGE_4, b5);
args.put(DBAdapter.KEY_MESSAGE_5, b6);
args.put(DBAdapter.KEY_MESSAGE_6, b7);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_1, b8);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_2, b9);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_3, b10);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_TYPE, b11);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_NEED, b12);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_OTHER, b13);
String where = "_id = " + mRowId.toString();
myDB.update(DBAdapter.DATABASE_TABLE, args,where, null);
dba.close();
showDialog(DIALOG_ID);
}
}
});
添加 try/catch 后
try{
myDB.beginTransaction();
dba.open();
ContentValues args = new ContentValues();
args.put(DBAdapter.KEY_MESSAGE_1, b2);
args.put(DBAdapter.KEY_MESSAGE_2, b3);
args.put(DBAdapter.KEY_MESSAGE_3, b4);
args.put(DBAdapter.KEY_MESSAGE_4, b5);
args.put(DBAdapter.KEY_MESSAGE_5, b6);
args.put(DBAdapter.KEY_MESSAGE_6, b7);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_1, b8);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_2, b9);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_3, b10);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_TYPE, b11);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_NEED, b12);
args.put(DBAdapter.KEY_YOUR_CURRENT_WEBSITE_OTHER, b13);
String where =DBAdapter.KEY_ROWID +"=" + mRowId.toString();
myDB.update(DBAdapter.DATABASE_TABLE, args,where, null);
myDB.setTransactionSuccessful();
dba.close();
showDialog(DIALOG_ID);
}
catch(Exception e){
e.printStackTrace();
}
finally {
myDB.endTransaction();
}
}
}
});
现在我收到这个错误
01-29 17:52:38.874: W/System.err(9257): java.lang.NullPointerException
01-29 17:52:38.874: W/System.err(9257): at com.example.sales.Newform_Screen2$3.onClick(Newform_Screen2.java:150)
01-29 17:52:38.874: W/System.err(9257): at android.view.View.performClick(View.java:4084)
01-29 17:52:38.883: W/System.err(9257): at android.view.View$PerformClick.run(View.java:16966)
01-29 17:52:38.883: W/System.err(9257): at android.os.Handler.handleCallback(Handler.java:615)
01-29 17:52:38.883: W/System.err(9257): at android.os.Handler.dispatchMessage(Handler.java:92)
01-29 17:52:38.893: W/System.err(9257): at android.os.Looper.loop(Looper.java:137)
01-29 17:52:38.893: W/System.err(9257): at android.app.ActivityThread.main(ActivityThread.java:4745)
01-29 17:52:38.893: W/System.err(9257): at java.lang.reflect.Method.invokeNative(Native Method)
01-29 17:52:38.893: W/System.err(9257): at java.lang.reflect.Method.invoke(Method.java:511)
01-29 17:52:38.893: W/System.err(9257): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-29 17:52:38.893: W/System.err(9257): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)