我创建了一个数据库，它给了我这个错误。
这是logcat。
02-19 15:33:38.057 1273-1273/tubapps.dbtutorial E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{tubapps.dbtutorial/tubapps.dbtutorial.EditIncome}: java.lang.NullPointerException: println needs a message
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException: println needs a message
at android.util.Log.println_native(Native Method)
at android.util.Log.d(Log.java:138)
at tubapps.dbtutorial.EditIncome.onCreate(EditIncome.java:66)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
这是我的活动。
public class EditIncome extends ActionBarActivity {
DBHelper helper = new DBHelper(this);
private Calendar calendar;
private TextView dateView;
private int year, month, day;
TextView payer;
TextView amount;
Spinner payments;
Spinner category;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_income);
dateView = (TextView) findViewById(R.id.input_date);
calendar = Calendar.getInstance();
year = calendar.get(Calendar.YEAR);
month = calendar.get(Calendar.MONTH);
day = calendar.get(Calendar.DAY_OF_MONTH);
showDate(year, month + 1, day);
payer = (TextView) findViewById(R.id.input_payer);
amount = (TextView) findViewById(R.id.input_amount);
dateView = (TextView) findViewById(R.id.input_date);
payments = (Spinner) findViewById(R.id.incomeNumber);
ArrayAdapter<CharSequence> payments_adapter = ArrayAdapter.createFromResource(this,
R.array.recurring_income, android.R.layout.simple_spinner_item);
payments_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
payments.setAdapter(payments_adapter);
category = (Spinner) findViewById(R.id.categoryIncome);
ArrayAdapter<CharSequence> income_adapter = ArrayAdapter.createFromResource(this,
R.array.category_income, android.R.layout.simple_spinner_item);
income_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
category.setAdapter(income_adapter);
Intent objIntent = getIntent();
String incomeId = objIntent.getStringExtra("incomeId");
Log.d("Reading: ", "Reading all incomes..");
HashMap<String, String> incomeList = helper.getIncomeInfo(incomeId);
Log.d("incomeAmount",incomeList.get("incomeAmount"));
Log.d("incomePayer",incomeList.get("incomePayer"));
Log.d("incomeDate",incomeList.get("incomeDate"));
Log.d("incomeCategory",incomeList.get("incomeCategory"));
Log.d("incomePayments",incomeList.get("incomePayments"));
if(incomeList.size()!=0) {
amount.setText(incomeList.get("incomeAmount"));
payer.setText(incomeList.get("incomePayer"));
dateView.setText(incomeList.get("incomeDate"));
payments.setSelection(getIndex(payments, "incomePayments"));
category.setSelection(getIndex(category, "incomeCategory"));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_edit_income, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void setDate(View view) {
showDialog(999);
}
@Override
protected Dialog onCreateDialog(int id) {
// TODO Auto-generated method stub
if (id == 999) {
return new DatePickerDialog(this, myDateListener, year, month, day);
}
return null;
}
private DatePickerDialog.OnDateSetListener myDateListener
= new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub
// arg1 = year
// arg2 = month
// arg3 = day
showDate(arg1, arg2 + 1, arg3);
}
};
private void showDate(int year, int month, int day) {
dateView.setText(new StringBuilder().append(day).append("/")
.append(month).append("/").append(year));
}
public void editIncome(View view) {
HashMap<String, String> queryValues = new HashMap<String, String>();
payer = (TextView) findViewById(R.id.input_payer);
amount = (TextView) findViewById(R.id.input_amount);
dateView = (TextView) findViewById(R.id.input_date);
payments = (Spinner) findViewById(R.id.incomeNumber);
ArrayAdapter<CharSequence> payments_adapter = ArrayAdapter.createFromResource(this,
R.array.recurring_income, android.R.layout.simple_spinner_item);
payments_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
payments.setAdapter(payments_adapter);
category = (Spinner) findViewById(R.id.categoryIncome);
ArrayAdapter<CharSequence> income_adapter = ArrayAdapter.createFromResource(this,
R.array.category_income, android.R.layout.simple_spinner_item);
income_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
category.setAdapter(income_adapter);
Intent objIntent = getIntent();
String incomeId = objIntent.getStringExtra("incomeId");
queryValues.put("incomeId", incomeId);
queryValues.put("incomeAmount", amount.getText().toString());
queryValues.put("incomePayer", payer.getText().toString());
queryValues.put("incomeDate", dateView.getText().toString());
queryValues.put("incomeCategory", category.getSelectedItem().toString());
queryValues.put("incomePayments", payments.getSelectedItem().toString());
helper.updateIncome(queryValues);
this.callHomeActivity(view);
}
public void removeIncome(View view) {
Intent objIntent = getIntent();
String incomeId = objIntent.getStringExtra("incomeId");
helper.deleteIncome(incomeId);
this.callHomeActivity(view);
}
public void callHomeActivity(View view) {
Intent objIntent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(objIntent);
}
private int getIndex(Spinner spinner, String myString) {
int index = 0;
for (int i = 0; i < spinner.getCount(); i++) {
if (spinner.getItemAtPosition(i).equals(myString)) {
index = i;
}
}
return index;
}
}
P.S。 66行是Log.d("incomeAmount",incomeList.get("incomeAmount"));
我在互联网上找到了一些东西，但它并没有解决我的问题。我也是初学者，所以请不要过度反应。
答案 0 :(得分：0)
incomeList.get（“incomeAmount”）返回null。因此，如果字段填写正确，则必须检查填充HashTable的函数。