为什么ClassCastException？

Question

我在这一行得到了一个ClassCastException。 .putStringArrayListExtra（“list”，（ArrayList）listItems））;我正在尝试将ListView的内容发送到另一个Activity。

我不知道为什么。谁能帮忙。

private double overallTotalproduct;
public static TextView resultTextView;

ArrayList<String> listItems=new ArrayList<String>();
ArrayAdapter<String> adapter;

private Button whateverButton;
   TextView inputPrice;
   RelativeLayout lay1;
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.menuview);

    adapter=new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1,
            listItems);
            setListAdapter(adapter);

whateverButton = (Button)findViewById(R.id.whateverButton);
inputPrice= (TextView)findViewById(R.id.inputPrice);
lay1= (RelativeLayout)findViewById(R.id.lay1);


//Total Box
final TextView textViewtotalproduct = (TextView) findViewById(R.id.inputPrice);

final TextView textView1 = (TextView) findViewById(R.id.m1aa);
final String stringm1aa = textView1.getText().toString();
final double intm1aa = Double.parseDouble(stringm1aa);
final TextView textView1a = (TextView) findViewById(R.id.m1a);
final String stringm1a = textView1a.getText().toString();

  lay1.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        listItems.add("$"+intm1aa +"-"+ stringm1a);
        adapter.notifyDataSetChanged();
        resultTextView.setText(stringm1a);
        overallTotalproduct =  intm1aa + overallTotalproduct;
        textViewtotalproduct.setText(String.valueOf(overallTotalproduct));
    }
});

  public void onwhateverPress(View v) {
  Intent whateverIntent = new Intent(this, WhateverActivity.class);

 if (whateverResult.iswhateveranicewhatever()) {

 final TextView daplane =(TextView)findViewById(R.id.date);
 String watch = daplane.getText().toString();



 startActivity(new Intent(MenuView1Activity.this,RecordCheckActivity.class)
.putExtra("date",(CharSequence)watch)

//THIS IS THE LINE IM GETTING THE ERROR ON
.putStringArrayListExtra("list", (ArrayList<String>) listItems));
finish();

第二项活动

Intent id11 = getIntent();
if (id11.getCharSequenceExtra("list") != null) {
final TextView setmsg = (TextView)findViewById(R.id.saleNotes);
setmsg.setText(id11.getCharSequenceExtra("list"));              

}

Answer 1

你已经拥有：

ArrayList<String> listItems=new ArrayList<String>();

那你为什么要在这里将listItems转换为ArrayList ???：

.putStringArrayListExtra("list", (ArrayList<String>) listItems));

只需执行以下操作：

.putStringArrayListExtra("list", listItems));