Question

我正在尝试将从spinner中选择的值传递给另一个类，但它传递null。

protected int secondsToUse;

final String titles[] = {
  "1 Second","2 Seconds", "3 Seconds","4 Seconds",
  "5 Seconds","6 Seconds","7 Seconds","8 Seconds","9 Seconds","10 Seconds"
};

mSeconds = (Spinner) view.findViewById(R.id.secondsSpinner);

 ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, titles);
        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    mSeconds.setAdapter(arrayAdapter);
mSeconds.setOnItemSelectedListener(
    new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
            // secondsToUse is declared a as int variable above
            secondsToUse = position + 1;
        }



// passing the value to another class.// PASSES AS NULL
Intent recipientsIntent = new Intent(getActivity(), RecipientsActivity.class);
                    recipientsIntent.putExtra("key1", secondsToUse);
                    startActivity(recipientsIntent);

// retrieving the value //retrieves as null
String Seconds = getIntent().getStringExtra("key1");
byte[] secs = Seconds.getBytes();

我正在尝试获取用户在微调器上选择的位置，因此我可以将其传递到计时器中以使图像自毁。目前我得到了空白

Answer 1

修改：我忘了在第一个回答中考虑getIntExtra()采用两个参数。它需要识别＆＃34;键＆＃34;和默认值。

要在RecipientsActivity中检索所选行的位置，请保留您的代码。然后，在onCreate()的{{1}}中：

RecipientsActivity

Answer 2

只需将getStringExtra()替换为getIntExtra()

int defaultSecond = -1;
int seconds = getIntent().getIntExtra("key1",defaultSecond);

原因：因为您在int

中放置了String而不是putExtra("key1", secondsToUse);

此外，在命名变量时使用camel case。使用秒而不是秒。我希望这有帮助！

Answer 3

您为什么使用getStringExtra()？

您正在传递一个整数，因此接收一个整数

// retrieving the value
int seconds = getIntent().getIntExtra("key1");

如果你需要它作为字符串使用

String secondsAsString = String.valueOf(seconds);

Answer 4

将getStringExtra()替换为getIntExtra()

int default = -1;
String val = getIntent().getIntExtra("key1",default);
if(val == default){
  //Log, exception, no value etc.
}
String Seconds = String.valueOf(val);
byte[] secs = Seconds.getBytes();

从Activity

中选择元素时，请致电开始ListView

mSeconds.setOnItemSelectedListener(
    new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
            // secondsToUse is declared a as int variable above
            secondsToUse = position + 1;
            // passing the value to another class.// PASSES AS NULL
            Intent recipientsIntent = new Intent(getActivity(),     RecipientsActivity.class);
            recipientsIntent.putExtra("key1", secondsToUse);
            startActivity(recipientsIntent);
        }

Answer 5

在OnItemSelectListner中使用Explicit Intent调用下一个Activity 试试这个

mSeconds.setOnItemSelectedListener（new AdapterView.OnItemSelectedListener（）{

@覆盖

public void onItemSelected（AdapterView parentView，View selectedItemView，int

位置，长身份证）{

               secondToUse = String.valueOf(position + 1);
               Intent intent = new Intent(CurrentClass.this,NewClass.Class);
               putInentExtra("Key1","secondTouse");
               startActivity(intent);

        }

在你的下一个活动中得到意图 -

意图i = getIntent（）;

String getPosition = i.getStringExtra（“Key1”）;

享受：）

将所选值传递给另一个Android类

5 个答案: