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我是新应用程序开发人员，迄今为止我的应用程序按预期工作，但仅在Android Studio的设备上启动时才适用。例如，我有一个实例变量，我在onCreate（）方法中给出1的值。当我从android studio启动应用程序到我的设备上时，它工作正常，变量的值为1.但是，当我从我的设备启动它而不使用android studio时，变量的值为0.我有还发现我会在我知道应该有一个值的变量上得到一堆NullPointerExceptions，并且再次从Android Studio启动时会起作用，但在从设备启动时不起作用。Android Studio应用程序在我从Android Studio启动时运行，但不是从设备启动时运行
这里是MainActivity
public class MainActivity extends AppCompatActivity
{
private ArrayList<String> arrayList;
private ArrayList<ListItem> itemList;
private ArrayAdapter<String> adapter;
private EditText txtInput;
private int payRoll;
private String value;
private Intent mainToPayroll;
private int hours;
private int earnings;
private ArrayList<Integer> rollList;
private ArrayList<Integer> hourList;
private ArrayList<Integer> wageList;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rollList = new ArrayList<>(0);
hourList = new ArrayList<>(0);
wageList = new ArrayList<>(0);
payRoll = 1;
Bundle bun = getIntent().getExtras();
if(bun != null)
{
rollList = bun.getIntegerArrayList("rolls");
hourList = bun.getIntegerArrayList("hours");
wageList = bun.getIntegerArrayList("wages");
payRoll = bun.getInt("roll");
}
ListView listView = (ListView) findViewById(R.id.listv);
String[] items = {};
arrayList = new ArrayList<>(Arrays.asList(items));
itemList = new ArrayList<>(0);
adapter = new ArrayAdapter<String>(this, R.layout.list_item, R.id.txtitem, arrayList);
listView.setAdapter(adapter);
Button btAdd = (Button) findViewById(R.id.btadd);
mainToPayroll = new Intent(this, PayrollActivity.class);
if(rollList != null)
{
for (int i = 0; i < rollList.size(); i++) {
ListItem newItem = new ListItem(rollList.get(i), hourList.get(i), wageList.get(i));
arrayList.add(newItem.toString());
itemList.add(newItem);
adapter.notifyDataSetChanged();
}
rollList.clear();
hourList.clear();
wageList.clear();
}
btAdd.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
ListItem newItem = new ListItem(payRoll, 0, 0);
arrayList.add(newItem.toString());
itemList.add(newItem);
adapter.notifyDataSetChanged();
payRoll++;
}
});
listView.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
value = (String)adapter.getItem(position);
ListItem item = itemList.get(position);
Bundle info = new Bundle();
info.putString("val", value);
info.putInt("hours", item.getHours());
info.putInt("wage", item.getWages());
info.putInt("pos", position);
if(itemList.size() > 0)
{
for (ListItem items : itemList)
{
rollList.add(items.getPayroll());
hourList.add(items.getHours());
wageList.add(items.getWages());
}
}
info.putIntegerArrayList("rolls", rollList);
info.putIntegerArrayList("hours", hourList);
info.putIntegerArrayList("wages", wageList);
info.putInt("roll", payRoll);
info.putBoolean("rest", restore);
mainToPayroll.putExtras(info);
startActivity(mainToPayroll);
}
});
}
每当在列表视图中的项目被点击
public class PayrollActivity extends AppCompatActivity
{
private static TextView text;
private String payrollNumber;
private int payrollHrs;
private int payrollWages;
private int position;
private Intent payrollToMain;
private Button returnButton;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_payroll);
final Bundle info = getIntent().getExtras();
System.out.print(getIntent().getType());
payrollNumber = info.getString("val");
payrollHrs = info.getInt("hours");
payrollWages = info.getInt("wage");
position = info.getInt("pos");
payrollToMain = new Intent(this, MainActivity.class);
returnButton = (Button) findViewById(R.id.btnRtrn);
returnButton.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
Bundle thing = new Bundle();
thing.putIntegerArrayList("rolls", info.getIntegerArrayList("rolls"));
thing.putIntegerArrayList("hours", info.getIntegerArrayList("hours"));
thing.putIntegerArrayList("wages", info.getIntegerArrayList("wages"));
thing.putInt("roll", info.getInt("roll"));
thing.putBoolean("rest", info.getBoolean("rest"));
payrollToMain.putExtras(thing);
startActivity(payrollToMain);
}
});
text = (TextView) findViewById(R.id.title);
text.setText(payrollNumber);
}
public static void setLabelText(String val)
{
text.setText(val);
}
这是我该走的列表视图中的项目创建的类此活动开始
public class ListItem
{
private int payroll;
private int hrs;
private int wages;
public ListItem(int roll, int hours, int wag)
{
payroll = roll;
hrs = hours;
wages = wag;
}
public int getPayroll()
{
return payroll;
}
public int getHours()
{
return hrs;
}
public int getWages()
{
return wages;
}
public void setPayroll(int roll)
{
payroll = roll;
}
public void setHrs(int hours)
{
hrs = hours;
}
public void setWages(int wage)
{
wages = wage;
}
public String toString()
{
return "Payroll " + payroll + "\n" + hrs + " hours\n$" + wages;
}
您是否使用Instant Run？ – ifiok
向我们展示一些代码，没有它我们不能帮你 – Konrad
是的，我正在使用即时运行。 –