我有一个用户签名的活动，我想保留下一个活动的用户名。 这就是我所拥有的：
public void onClick(View v)
{
// get The User name and Password
String userName=editTextUserName.getText().toString();
String password=editTextPassword.getText().toString();
String user = userName;
// fetch the Password from database for respective user name
String storedPassword=loginDataBaseAdapter.getSinlgeEntry(userName);
// check if the Stored password matches with Password entered by user
if(password.equals(storedPassword))
{
Toast.makeText(MainActivity.this, "Congrats: Login Successfull", Toast.LENGTH_LONG).show();
//dialog.dismiss();
Intent intentLetterChecker=new Intent(MainActivity.this,HomeActivity.class);
intentLetterChecker.putExtra("Username", user);
startActivity(intentLetterChecker);
}
}
注意：我还尝试过没有String用户，只使用userName但没有区别。然后在我的信函检查意图我全局声明当前用户和我的onCreate我有：
Bundle extras = getIntent().getExtras();
currentUser = extras.getString("Username");
这是我的logcat：
05-13 11:41:41.424: E/AndroidRuntime(8971): FATAL EXCEPTION: main
05-13 11:41:41.424: E/AndroidRuntime(8971): Process: com.gmail.Sheridjohn.letterchecker, PID: 8971
05-13 11:41:41.424: E/AndroidRuntime(8971): java.lang.NullPointerException
05-13 11:41:41.424: E/AndroidRuntime(8971): at com.gmail.Sheridjohn.letterchecker.LowerCaseActivity.onGesturePerformed(LowerCaseActivity.java:88)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.gesture.GestureOverlayView.fireOnGesturePerformed(GestureOverlayView.java:729)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.gesture.GestureOverlayView.access$400(GestureOverlayView.java:55)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.gesture.GestureOverlayView$FadeOutRunnable.run(GestureOverlayView.java:744)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.os.Handler.handleCallback(Handler.java:733)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.os.Handler.dispatchMessage(Handler.java:95)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.os.Looper.loop(Looper.java:136)
05-13 11:41:41.424: E/AndroidRuntime(8971): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-13 11:41:41.424: E/AndroidRuntime(8971): at java.lang.reflect.Method.invokeNative(Native Method)
05-13 11:41:41.424: E/AndroidRuntime(8971): at java.lang.reflect.Method.invoke(Method.java:515)
05-13 11:41:41.424: E/AndroidRuntime(8971): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-13 11:41:41.424: E/AndroidRuntime(8971): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-13 11:41:41.424: E/AndroidRuntime(8971): at dalvik.system.NativeStart.main(Native Method)
我的应用程序记录了一个用户，显示了一个字母表，供他们绘制，每个字母有两个计数器。当用户获得正确的字母时，一个递增，而当另一个不正确时，另一个递增。我想将此信息插入到我的SQLite数据库中，因为这似乎是最明智的方法。所以我的信函检查器中的插入方法如下：
public void insertCorrectInt(String user, String letter,int value)
{
ContentValues newValues = new ContentValues();
// Assign values for each row.
newValues.put("USERNAME", user);
newValues.put("LETTER", letter);
newValues.put("ISCORRECT",value);
// Insert the row into table
db.insert("LOGIN", null, newValues);
}
我称之为：
if(letters[i].equals("a"))
{
correctCountera++;
db.insertCorrectInt(currentUser,"a",correctCountera);
}
if(letters[i].equals("b"))
{
correctCounterb++;
db.insertCorrectInt(currentUser,"b",correctCounterb);
}
非常感谢任何帮助/建议，谢谢！
编辑： 我忘记发布我的onGesturePerformed（）抱歉！这是漫长而有点暴力的力量：
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture)
{
ArrayList<Prediction> predictions = new ArrayList<Prediction>(); //this methods asks to recognize the gesture against loaded gesture library
predictions = mLibrary.recognize(gesture);
// We want at least one prediction
if (predictions.size() > 0)
{
Prediction prediction = predictions.get(0); //get the 1st prediction auto generated for you by Android
// We want at least some confidence in the result
if (prediction.score > 1.0 && prediction.name.equals(letters[i]))
{
// Show the spell
//Toast.makeText(MainActivity.this, prediction.name, Toast.LENGTH_SHORT).show();
AlertDialog.Builder correctAlertDialogBuilder = new AlertDialog.Builder(LowerCaseActivity.this);
// set title
correctAlertDialogBuilder.setTitle("Correct!");
if(letters[i].equals("a"))
{
correctCountera++;
db.insertCorrectInt(currentUser,"a",correctCountera);
}
if(letters[i].equals("b"))
{
correctCounterb++;
db.insertCorrectInt(currentUser,"b",correctCounterb);
}
if(letters[i].equals("c"))
{
correctCounterc++;
db.insertCorrectInt(currentUser,"c",correctCounterc);
}
if(letters[i].equals("d"))
{
correctCounterd++;
db.insertCorrectInt(currentUser,"d",correctCounterd);
}
if(letters[i].equals("e"))
{
correctCountere++;
db.insertCorrectInt(currentUser,"e",correctCountere);
}
if(letters[i].equals("f"))
{
correctCounterf++;
db.insertCorrectInt(currentUser,"f",correctCounterf);
}
if(letters[i].equals("g"))
{
correctCounterg++;
db.insertCorrectInt(currentUser,"g",correctCounterg);
}
if(letters[i].equals("h"))
{
correctCounterh++;
db.insertCorrectInt(currentUser,"h",correctCounterh);
}
if(letters[i].equals("i"))
{
correctCounteri++;
db.insertCorrectInt(currentUser,"i",correctCounteri);
}
if(letters[i].equals("j"))
{
correctCounterj++;
db.insertCorrectInt(currentUser,"j",correctCounterj);
}
if(letters[i].equals("k"))
{
correctCounterk++;
db.insertCorrectInt(currentUser,"k",correctCounterk);
}
if(letters[i].equals("l"))
{
correctCounterk++;
db.insertCorrectInt(currentUser,"l",correctCounterl);
}
if(letters[i].equals("m"))
{
correctCounterm++;
db.insertCorrectInt(currentUser,"m",correctCounterm);
}
if(letters[i].equals("n"))
{
correctCountern++;
db.insertCorrectInt(currentUser,"n",correctCountern);
}
if(letters[i].equals("o"))
{
correctCountero++;
db.insertCorrectInt(currentUser,"o",correctCountero);
}
if(letters[i].equals("p"))
{
correctCounterp++;
db.insertCorrectInt(currentUser,"p",correctCounterp);
}
if(letters[i].equals("q"))
{
correctCounterq++;
db.insertCorrectInt(currentUser,"q",correctCounterq);
}
if(letters[i].equals("r"))
{
correctCounterr++;
db.insertCorrectInt(currentUser,"CORRECTr",correctCounterr);
}
if(letters[i].equals("s"))
{
correctCounters++;
db.insertCorrectInt(currentUser,"s",correctCounters);
}
if(letters[i].equals("t"))
{
correctCountert++;
db.insertCorrectInt(currentUser,"t",correctCountert);
}
if(letters[i].equals("u"))
{
correctCounteru++;
db.insertCorrectInt(currentUser,"u",correctCounteru);
}
if(letters[i].equals("v"))
{
correctCounterv++;
db.insertCorrectInt(currentUser,"v",correctCounterv);
}
if(letters[i].equals("w"))
{
correctCounterw++;
db.insertCorrectInt(currentUser,"w",correctCounterw);
}
if(letters[i].equals("x"))
{
correctCounterx++;
db.insertCorrectInt(currentUser,"x",correctCounterx);
}
if(letters[i].equals("y"))
{
correctCountery++;
db.insertCorrectInt(currentUser,"y",correctCountery);
}
if(letters[i].equals("z"))
{
correctCounterz++;
db.insertCorrectInt(currentUser,"z",correctCounterz);
}
// set dialog message
correctAlertDialogBuilder
.setMessage("Would you like to move on or try again?")
.setCancelable(false)
.setPositiveButton("Move on",new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog,int id)
{
// if this button is clicked, increment i and close alert
if(i == 25)
{
i = 0;
updateTextView(guide);
}
else
{
i++;
updateTextView(guide);
}
dialog.cancel();
}})
.setNegativeButton("Try Again",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id)
{
// if this button is clicked, just close the dialog box and do nothing
dialog.cancel();
}});
// create alert dialog
AlertDialog correctDialog = correctAlertDialogBuilder.create();
// show it
correctDialog.show();
}
else
{
AlertDialog.Builder incorrectAlertDialogBuilder = new AlertDialog.Builder(LowerCaseActivity.this);
// set title
incorrectAlertDialogBuilder.setTitle("Incorrect!");
/*if(letters[i] == "a")
{
incorrectCountera++;
loginDataBaseAdapter.insertInt("INCORRECTa",incorrectCountera);
}
if(letters[i] == "b")
{
incorrectCounterb++;
loginDataBaseAdapter.insertInt("INCORRECTb",incorrectCounterb);
}
if(letters[i] == "c")
{
incorrectCounterc++;
loginDataBaseAdapter.insertInt("INCORRECTc",incorrectCounterc);
}
if(letters[i] == "d")
{
incorrectCounterd++;
loginDataBaseAdapter.insertInt("INCORRECTd",incorrectCounterd);
}
if(letters[i] =="e")
{
incorrectCountere++;
loginDataBaseAdapter.insertInt("INCORRECTe",incorrectCountere);
}
if(letters[i] == "f")
{
incorrectCounterf++;
loginDataBaseAdapter.insertInt("INCORRECTf",incorrectCounterf);
}
if(letters[i] == "g")
{
incorrectCounterg++;
loginDataBaseAdapter.insertInt("INCORRECTg",incorrectCounterg);
}
if(letters[i] == "h")
{
incorrectCounterh++;
loginDataBaseAdapter.insertInt("INCORRECTh",incorrectCounterh);
}
if(letters[i] == "i")
{
incorrectCounteri++;
loginDataBaseAdapter.insertInt("INCORRECTi",incorrectCounteri);
}
if(letters[i] == "j")
{
incorrectCounterj++;
loginDataBaseAdapter.insertInt("INCORRECTj",incorrectCounterj);
}
if(letters[i] == "k")
{
incorrectCounterk++;
loginDataBaseAdapter.insertInt("INCORRECTk",incorrectCounterk);
}
if(letters[i] == "l")
{
incorrectCounterk++;
loginDataBaseAdapter.insertInt("INCORRECTl",incorrectCounterl);
}
if(letters[i] == "m")
{
incorrectCounterm++;
loginDataBaseAdapter.insertInt("INCORRECTm",incorrectCounterm);
}
if(letters[i] == "n")
{
incorrectCountern++;
loginDataBaseAdapter.insertInt("INCORRECTn",incorrectCountern);
}
if(letters[i] == "o")
{
incorrectCountero++;
loginDataBaseAdapter.insertInt("INCORRECTo",incorrectCountero);
}
if(letters[i] == "p")
{
incorrectCounterp++;
loginDataBaseAdapter.insertInt("INCORRECTp",incorrectCounterp);
}
if(letters[i] == "q")
{
incorrectCounterq++;
loginDataBaseAdapter.insertInt("INCORRECTq",incorrectCounterq);
}
if(letters[i] == "r")
{
incorrectCounterr++;
loginDataBaseAdapter.insertInt("INCORRECTr",incorrectCounterr);
}
if(letters[i] == "s")
{
incorrectCounters++;
loginDataBaseAdapter.insertInt("INCORRECTs",incorrectCounters);
}
if(letters[i] == "t")
{
incorrectCountert++;
loginDataBaseAdapter.insertInt("INCORRECTt",incorrectCountert);
}
if(letters[i] == "u")
{
correctCounteru++;
loginDataBaseAdapter.insertInt("INCORRECTu",correctCounteru);
}
if(letters[i] == "v")
{
incorrectCounterv++;
loginDataBaseAdapter.insertInt("INCORRECTv",incorrectCounterv);
}
if(letters[i] == "w")
{
incorrectCounterw++;
loginDataBaseAdapter.insertInt("INCORRECTw",incorrectCounterw);
}
if(letters[i] == "x")
{
incorrectCounterx++;
loginDataBaseAdapter.insertInt("INCORRECTx",incorrectCounterx);
}
if(letters[i] == "y")
{
incorrectCountery++;
loginDataBaseAdapter.insertInt("INCORRECTy",incorrectCountery);
}
if(letters[i] == "z")
{
correctCounterz++;
loginDataBaseAdapter.insertInt("INCORRECTi",correctCounteri);
}*/
// set dialog message
incorrectAlertDialogBuilder
.setMessage("Would you like to move on or try again?")
.setCancelable(false)
.setPositiveButton("Move on",new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog,int id)
{
// if this button is clicked, increment i and close alert
if(i == 25)
{
i = 0;
updateTextView(guide);
}
else
{
i++;
updateTextView(guide);
}
dialog.cancel();
}})
.setNegativeButton("Try Again",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id)
{
// if this button is clicked, just close the dialog box and do nothing
dialog.cancel();
}});
// create alert dialog
AlertDialog incorrectDialog = incorrectAlertDialogBuilder.create();
incorrectDialog.show();
}
}
Java第88行是{
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture)