当我需要将一些数据从一个Activity传输到另一个时，我的代码存在问题。
首先Activity（ViewCashflow）我希望将一些数据从ViewCashflow转移到第二Activity（NewTransaction）。这里运行良好，没有错误，数据传输成功。但是，我不知道当我直接运行第二个Activity时发生了什么（不是像我之前的Activity那样，当我传输数据时）我在使用的方法上得到了空指针异常从第一个Activity收到数据。
我试图在那里找到所有的东西，但仍未解决。在其他Activity（ViewCategory和AddCategory）中，我正在执行相同的操作（将数据从ViewCategory传输到AddCategory），其运行良好且没有错误当我直接运行AddCategory但代码与两个Activity完全相同时，我得到了错误。
请高手帮帮我。 谢谢。
错误报告给我这个：
引起：java.lang.NullPointerException：尝试在空对象引用上调用虚方法'boolean android.os.Bundle.getBoolean（java.lang.String）' at com.example.ever_ncn.cashflow.NewTransaction.onCreate（NewTransaction.java:68）
NB。这是我的第一个Activity（ViewCashflow）
public class ViewCashflow extends ActionBarActivity {
private SQLiteDatabase db;
private static Button BtnIAddCateg;
private static Button BtnICancelCateg;
private static final String TAG = CategorySetting.class.getSimpleName();
DatabaseHelper dBHelper = new DatabaseHelper (this);
private ListView list;
private ArrayList<String> arrTransId = new ArrayList<String>();
private ArrayList<String> arrTransName = new ArrayList<String>();
private ArrayList<String> arrTransAmount = new ArrayList<String>();
private ArrayList<String> arrTransType= new ArrayList<String>();
private ArrayList<String> arrTransDate= new ArrayList<String>();
private ArrayList<String> arrCategId= new ArrayList<String>();
private AlertDialog.Builder build;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_cashflow);
displayData();
}
//udah beres udah bisa show, tinggal action click udh bisa tp value blm pindah,,
//penggunaan Radio Button belum nanti di NewTrans
private void displayData() {
db = dBHelper.getReadableDatabase();
Cursor mCursor = db.rawQuery("SELECT * FROM " + dBHelper.TABLE_Trans_NAME, null);
list = (ListView)findViewById(android.R.id.list);
arrTransId.clear();
arrTransName.clear();
arrTransAmount.clear();
arrTransType.clear();
arrTransDate.clear();
arrCategId.clear();
if (mCursor.moveToFirst()) {
do {
arrTransId.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL1)));
arrTransName.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL2)));
arrTransAmount.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL3)));
arrTransType.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL4)));
arrTransDate.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL5)));
arrCategId.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.TOL6)));
} while (mCursor.moveToNext());
}
DisplayAdapterTrans disadptr = new DisplayAdapterTrans(ViewCashflow.this, arrTransId, arrTransName,
arrTransAmount, arrTransType, arrTransDate, arrCategId);
list.setAdapter(disadptr);
mCursor.close();
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
//click to update data
// namanya blom diubah coeg
Intent i = new Intent(getApplicationContext(), NewTransaction.class);
i.putExtra("TransId", arrTransId.get(arg2));
i.putExtra("TransName", arrTransName.get(arg2));
i.putExtra("TransAmount", arrTransAmount.get(arg2));
i.putExtra("TransType", arrTransType.get(arg2));
i.putExtra("TransDate", arrTransDate.get(arg2));
i.putExtra("TransCategId", arrCategId.get(arg2));
i.putExtra("update", true);
startActivity(i);
}
});
}
@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_view_cashflow, 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);
}
}
这是第二个Activity（NewTransaction）
public class NewTransaction extends ActionBarActivity {
Button btnIDate;
Button btnIAdd;
Button btnICancel;
RadioButton RdIncome;
RadioButton RdOutcome;
EditText txtAmount, txtCashflow, txtType;
DatabaseHelper dbHelper = new DatabaseHelper(this);
SQLiteDatabase db;
MainActivity mainAct = new MainActivity();
int year_x, month_x, day_x;
static final int DIALOG_ID=0;
public static long dateSelected;
public static Integer intAmount = null;
private boolean isUpdate;
private String id, transname, transamount, transtype, transdate, transcategid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new_transaction);
txtAmount = (EditText)findViewById(R.id.txtAmount);
txtCashflow = (EditText)findViewById(R.id.txtCashflow);
txtType = (EditText)findViewById(R.id.txtType);
RdIncome = (RadioButton)findViewById(R.id.RdBtnIncome);
RdOutcome = (RadioButton)findViewById(R.id.RdBtnOutcome);
final Calendar cal = Calendar.getInstance();
year_x = cal.get(Calendar.YEAR);
month_x = cal.get(Calendar.MONTH);
day_x = cal.get(Calendar.DAY_OF_MONTH);
TextView lblIDate = (TextView)findViewById(R.id.lblDate);
lblIDate.setText("Date selected : " + year_x + "-" + month_x + "-" + day_x);
//EditText lbltxt = (EditText)findViewById(R.id.txtType);
dateSelected = (year_x+month_x+day_x);
String catSelected = mainAct.getCatSelected();
//kena null object dsni entah knapa
showDialogOnClick();
isUpdate=getIntent().getExtras().getBoolean("update");
if(isUpdate)
{
id=getIntent().getExtras().getString("TransId");
transname=getIntent().getExtras().getString("TransName");
transamount=getIntent().getExtras().getString("TransAmount");
transtype=getIntent().getExtras().getString("TransType");
transdate=getIntent().getExtras().getString("CategDate");
transcategid=getIntent().getExtras().getString("CategCategId");
txtCashflow.setText(transname);
txtType.setText(transtype);
txtAmount.setText(transamount);
}
if(RdIncome.isChecked()){
txtType.setText("Income");
}else{
txtType.setText("Outcome");
}
onButtonClickButtonListener(dateSelected, catSelected);
}
public void showDialogOnClick(){
//TextView lblIDate = (TextView)findViewById(R.id.lblDate);
btnIDate = (Button)findViewById(R.id.btnDate);
btnIDate.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
showDialog(DIALOG_ID);
}
}
);
}
@Override
protected Dialog onCreateDialog(int id){
if (id == DIALOG_ID)
return new DatePickerDialog(this, dpickerListener , year_x, month_x, day_x);
return null;
}
public DatePickerDialog.OnDateSetListener dpickerListener
= new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
TextView lblIDate = (TextView)findViewById(R.id.lblDate);
year_x= year;
month_x = monthOfYear + 1;
day_x = dayOfMonth;
lblIDate.setText("Date selected : " + year_x + "-" + month_x + "-" + day_x);
Toast.makeText(NewTransaction.this, year_x + "/" + month_x + "/" + day_x, Toast.LENGTH_LONG).show();
//DateFormat.getDateInstance().format(myDatePicker.getCalendarView().getDate());
}
};
private void clearText(){
txtCashflow.clearComposingText();
txtAmount.clearComposingText();
txtType.clearComposingText();
}
public void onButtonClickButtonListener(final long dateSelected, final String catSelected){
btnIAdd = (Button)findViewById(R.id.btnAddTrans);
btnIAdd.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
/*if(RdIncome.isChecked()){
txtType.setText("Income");
}else{
txtType.setText("Outcome");
}*/
if (isUpdate) {
//update
Toast.makeText(NewTransaction.this, "Clicked", Toast.LENGTH_LONG).show();
intAmount = Integer.parseInt(txtAmount.getText().toString());
boolean isInserted = dbHelper.updateTransData(id, txtCashflow.getText().toString(),
intAmount, txtType.getText().toString(),
dateSelected, catSelected, null);
if (isInserted == true) {
Toast.makeText(NewTransaction.this, "Inserted", Toast.LENGTH_LONG).show();
clearText();
Intent intent = new Intent(
NewTransaction.this,
ViewCashflow.class
);
startActivity(intent);
} else
Toast.makeText(NewTransaction.this, "Not Inserted", Toast.LENGTH_LONG).show();
} else {
//insert
Toast.makeText(NewTransaction.this, "Clicked", Toast.LENGTH_LONG).show();
intAmount = Integer.parseInt(txtAmount.getText().toString());
boolean isInserted = dbHelper.insertTransData(txtCashflow.getText().toString(),
intAmount, txtType.getText().toString(),
dateSelected, catSelected, null);
if (isInserted == true) {
Toast.makeText(NewTransaction.this, "Inserted", Toast.LENGTH_LONG).show();
clearText();
Intent intent = new Intent(
NewTransaction.this,
ViewCashflow.class
);
startActivity(intent);
} else
Toast.makeText(NewTransaction.this, "Not Inserted", Toast.LENGTH_LONG).show();
}
}
});
btnICancel = (Button)findViewById(R.id.btnCancelTrans);
btnICancel.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(
NewTransaction.this,
MainActivity.class
);
startActivity(intent);
}
}
);
}
@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_new_transaction_, 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);
}
}
这是我的代码CategorySetting / ViewCategory（另一个Activity使用这种代码模式）：
public class CategorySetting extends Activity {
private SQLiteDatabase db;
private static Button BtnIAddCateg;
private static Button BtnICancelCateg;
private static final String TAG = CategorySetting.class.getSimpleName();
DatabaseHelper dBHelper = new DatabaseHelper (this);
private ListView list;
private ArrayList<String> arrCategId = new ArrayList<String>();
private ArrayList<String> arrCategName = new ArrayList<String>();
private ArrayList<String> arrCategNote = new ArrayList<String>();
private ArrayList<String> arrCategCurr = new ArrayList<String>();
private AlertDialog.Builder build;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_category_setting);
onButtonClickButtonListener();
//ListView list = getListView();
//showListView();
displayData();
onLongClickListener();
}
private void displayData() {
db = dBHelper.getReadableDatabase();
Cursor mCursor = db.rawQuery("SELECT * FROM " + dBHelper.TABLE_Categ_NAME, null);
list = (ListView)findViewById(android.R.id.list);
arrCategId.clear();
arrCategName.clear();
arrCategNote.clear();
arrCategCurr.clear();
if (mCursor.moveToFirst()) {
do {
arrCategId.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.COL1)));
arrCategName.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.COL2)));
arrCategNote.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.COL3)));
arrCategCurr.add(mCursor.getString(mCursor.getColumnIndex(dBHelper.COL4)));
} while (mCursor.moveToNext());
}
DisplayAdapter disadpt = new DisplayAdapter(CategorySetting.this, arrCategId, arrCategName, arrCategId, arrCategCurr);
list.setAdapter(disadpt);
mCursor.close();
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
//click to update data
Intent i = new Intent(getApplicationContext(), AddCategory.class);
i.putExtra("CategId", arrCategId.get(arg2));
i.putExtra("CategName", arrCategName.get(arg2));
i.putExtra("CategNote", arrCategNote.get(arg2));
i.putExtra("CategCurr", arrCategCurr.get(arg2));
i.putExtra("update", true);
startActivity(i);
}
});
}
private void onLongClickListener(){
ListView list = (ListView)findViewById(android.R.id.list);
list.setOnItemLongClickListener(new OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView<?> arg0, View arg1, final int arg2, long arg3) {
build = new AlertDialog.Builder(CategorySetting.this);
build.setTitle("Delete " + arrCategName.get(arg2));
build.setMessage("Do you want to delete ?");
build.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText( getApplicationContext(),
arrCategName.get(arg2) + " is deleted.", Toast.LENGTH_LONG).show();
db.delete(
dBHelper.TABLE_Categ_NAME, dBHelper.COL1 + "=" + arrCategId.get(arg2), null);
displayData();
dialog.cancel();
}
});
build.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
AlertDialog alert = build.create();
alert.show();
return true;
}
});
}
//ListView view = getListView();
//iew.addHeaderView(getLayoutInflater().inflate(R.layout.trans, null));
//db = dBHelper.getWritableDatabase();
//this.muat_ulang();
/*public void reload(){
try {
DatabaseHelper dbHelper = new DatabaseHelper(this.getApplicationContext());
db = dbHelper.getWritableDatabase();
Cursor c = db.rawQuery("SELECT CategName FROM " + tableName, null);
if (c != null ) {
if (c.moveToFirst()) {
do {
String categName = c.getString(c.getColumnIndex("CategName"));
}while (c.moveToNext());
}
}
} catch (SQLiteException se ) {
Log.e(getClass().getSimpleName(), "Could not create or Open the database");
} finally {
if (db != null)
db.execSQL("DELETE FROM " + tableName);
db.close();
}
}*/
@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_category_setting, menu);
return true;
}
public void onButtonClickButtonListener(){
BtnIAddCateg = (Button)findViewById(R.id.btnAddNewCateg);
BtnIAddCateg.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intentAddCateg = new Intent ("com.example.ever_ncn.cashflow.AddCategory");
intentAddCateg.putExtra("update", false);
startActivity(intentAddCateg);
startActivity(intentAddCateg);
}
}
);
BtnICancelCateg = (Button)findViewById(R.id.btnCancelCateg);
BtnICancelCateg.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(
CategorySetting.this,
MainActivity.class
);
startActivity(intent);
}
}
);
}
@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);
}
}
和AddCategory的这一个：
public class AddCategory extends ActionBarActivity {
private static Button BtnIAdd;
private static Button BtnICancel;
EditText txtcategname, txtType;
Spinner selectCurrency;
ArrayAdapter<CharSequence> adapterCurrency;
DatabaseHelper DbHelper = new DatabaseHelper(this);
SQLiteDatabase db;
private boolean isUpdate;
private String id, categname, categnote, categcurr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_category);
txtcategname = (EditText)findViewById(R.id.editText);
txtType = (EditText)findViewById(R.id.editText2);
BtnICancel = (Button)findViewById(R.id.btnCancel);
BtnIAdd = (Button)findViewById(R.id.btnAdd);
//spinner
selectCurrency = (Spinner) findViewById(R.id.spin_selectCurrency);
adapterCurrency = ArrayAdapter.createFromResource(this, R.array.CurrencyName,android.R.layout.simple_spinner_item );
adapterCurrency.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
selectCurrency.setAdapter(adapterCurrency);
selectCurrency.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getBaseContext(), parent.getItemAtPosition(position) + " selected", Toast.LENGTH_LONG).show();
String currencyValue = String.valueOf(parent.getSelectedItem());
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
isUpdate=getIntent().getExtras().getBoolean("update");
if(isUpdate)
{
id=getIntent().getExtras().getString("CategId");
categname=getIntent().getExtras().getString("CategName");
categnote=getIntent().getExtras().getString("CategNote");
categcurr=getIntent().getExtras().getString("CategCurr");
txtcategname.setText(categname);
txtType.setText(categnote);
}
addCategData();
}
@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_add_category, menu);
return true;
}
public void addCategData(){
BtnIAdd.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(AddCategory.this, "Clicked", Toast.LENGTH_LONG).show();
db=DbHelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put(DbHelper.COL2,categname );
values.put(DbHelper.COL3,categnote );
values.put(DbHelper.COL4,categcurr );
System.out.println("");
if(isUpdate)
{
//update database with new data
boolean isInserted = DbHelper.updateCategData(Integer.parseInt(id), txtcategname.getText().toString(),
txtType.getText().toString(), selectCurrency.getSelectedItem().toString(), null);
if (isInserted == true) {
Toast.makeText(AddCategory.this, "Updated", Toast.LENGTH_LONG).show();
//baru sampe dsni
Intent intent = new Intent(
AddCategory.this,
CategorySetting.class
);
startActivity(intent);
} else
Toast.makeText(AddCategory.this, "Not Inserted", Toast.LENGTH_LONG).show();
}
else
{
//insert data into database
boolean isInserted = DbHelper.insertCategData(txtcategname.getText().toString(),
txtType.getText().toString(), selectCurrency.getSelectedItem().toString(), null);
if (isInserted == true) {
Toast.makeText(AddCategory.this, "Inserted", Toast.LENGTH_LONG).show();
//baru sampe dsni
Intent intent = new Intent(
AddCategory.this,
CategorySetting.class
);
startActivity(intent);
} else
Toast.makeText(AddCategory.this, "Not Inserted", Toast.LENGTH_LONG).show();
}
//close database
db.close();
finish();
}
}
);
BtnICancel.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
}
);
}
@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);
}
}
答案 0 :(得分：0)
在ViewCashFlow类中尝试此操作：
Intent i = new Intent(Context.getApplicationContext(), NewTransaction.class);
答案 1 :(得分：0)
如果它是片段，则可以使用：
if (getArguments() != null) {
loginBody = getArguments().getParcelable(getActivity().getResources().getString(R.string.logInBodyParcelData));
}
/* } catch (Exception e) {
e.printStackTrace();
}*/
if (loginBody != null) {
setProfile();
}