您好我正在本[[{3}}中使用SQLite进行登录和注册的本教程，我遇到了这条线的问题，我不知道如何解码它。
这是我的家庭活动课程：
public class HomeActivity extends Activity
{
Button buttonSignIN,buttonSignUP;
LoginDataBaseAdapter loginDataBaseAdapter;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// create a instance of SQLite Database
loginDataBaseAdapter=new LoginDataBaseAdapter(this);
loginDataBaseAdapter=loginDataBaseAdapter.open();
// Get The Refference Of Buttons
buttonSignIN=(Button)findViewById(R.id.buttonSignIN);
buttonSignUP=(Button)findViewById(R.id.buttonSignUP);
// Set OnClick Listener on SignUp button
buttonSignUP.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
/// Create Intent for SignUpActivity and Start The Activity
Intent intentSignUP = new Intent(getApplicationContext(), SignUPActivity.class);
startActivity(intentSignUP);
}
});
}
// Methos to handleClick Event of Sign In Button
public void signIn(View V)
{
final Dialog dialog = new Dialog(HomeActivity.this);
dialog.setContentView(R.layout.login);
dialog.setTitle("Login");
// get the Refferences of views
final EditText nric=(EditText)dialog.findViewById(R.id.NRIC);
final EditText password=(EditText)dialog.findViewById(R.id.PASSWORD);
Button btnSignIn=(Button)dialog.findViewById(R.id.buttonSignIN);
// Set On ClickListener
btnSignIn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// get The User name and Password
String custNRIC =nric.getText().toString();
String custPassword=password.getText().toString();
// fetch the Password form database for respective user name
String storedPassword=loginDataBaseAdapter.getSinlgeEntry(custNRIC);
// check if the Stored password matches with Password entered by user
if(custPassword.equals(storedPassword))
{
Toast.makeText(HomeActivity.this, "Congrats: Login Successfull", Toast.LENGTH_LONG).show();
Intent intent = new Intent(HomeActivity.this, NextScreen.class);
startActivity(intent);
dialog.dismiss();
}
else
{
Toast.makeText(HomeActivity.this, "User Name or Password does not match", Toast.LENGTH_LONG).show();
}
}
});
dialog.show();
}
@Override
protected void onDestroy() {
super.onDestroy();
// Close The Database
loginDataBaseAdapter.close();
}
}
这是我的Logcat：
05-19 16:04:48.200 24149-24149/com.techblogon.loginexample D/dalvikvm﹕ GC_FOR_ALLOC freed 322K, 15% free 11495K/13432K, paused 15ms, total 15ms
05-19 16:04:48.220 24149-24149/com.techblogon.loginexample D/AndroidRuntime﹕ Shutting down VM
05-19 16:04:48.220 24149-24149/com.techblogon.loginexample W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41c18700)
05-19 16:04:48.220 24149-24149/com.techblogon.loginexample E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3838)
at android.view.View.performClick(View.java:4475)
at android.view.View$PerformClick.run(View.java:18786)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.view.View$1.onClick(View.java:3833)
at android.view.View.performClick(View.java:4475)
at android.view.View$PerformClick.run(View.java:18786)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.techblogon.loginexample.HomeActivity.signIn(HomeActivity.java:59)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.view.View$1.onClick(View.java:3833)
at android.view.View.performClick(View.java:4475)
at android.view.View$PerformClick.run(View.java:18786)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5419)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
at dalvik.system.NativeStart.main(Native Method)
05-19 16:04:50.470 24149-24149/com.techblogon.loginexample I/Process﹕ Sending signal. PID: 24149 SIG: 9