Question

我在活动A中有一个列表视图。我想总结从活动B返回活动A的总金额，但我不知道如何添加它们。

 double sum =0;

public void onActivityResult(int requestCode, int resultCode, Intent data) { // receive from Activity B and populate ListView A
     if (resultCode == RESULT_OK) {
         if (requestCode == PROJECT_REQUEST_CODE) {
             double ReceiveAmount = data.getDoubleExtra("amount",0);
             sum = + ReceiveAmount;
            totalAmount.setText(sum+")
             }
         }
     }
 }

假设在活动B中我返回金额5，然后我再次转到活动B并返回值10.我希望吐司显示值15而不是总是5。

修改

   @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) { // receive from Activity B and populate ListView A
            if (resultCode == RESULT_OK) {
                if (requestCode == PROJECT_REQUEST_CODE) {
                   double ReceiveAmount = data.getDoubleExtra("amount",0);
                    sum += ReceiveAmount;
                    if (mClickedPosition == -1) {  // if icon clicked
                        if (obj != null) {
                            obj.addNewItem(ReceiveAmount);
                            listview.setAdapter(obj);
             Toast.makeText(getApplicationContext(),sum+"",Toast.LENGTH_SHORT).show();
                            addOrRemoveFooter(sum);
                        }
                    } 
                }
            }
        }

  public void addOrRemoveFooter(double sum2) {
    if (search.size() == 0 && listview.getFooterViewsCount() > 0) {
        listview.removeFooterView(footerLayout);
        Toast.makeText(getApplication(),"In"+sum2+"",Toast.LENGTH_SHORT).show();
    } else if (listview.getFooterViewsCount() == 0 && search.size() > 0) {
        Toast.makeText(getApplication(),"Out"+sum2+"",Toast.LENGTH_SHORT).show();
        listview.addFooterView(footerLayout);
        listview.setAdapter(obj);
        totalAmount.setText(sum2 + "");
    }
    else
    {
        Toast.makeText(getApplicationContext(),"error",Toast.LENGTH_SHORT).show();
    }
}

吐司现在显示15，但是setText总是5 ...为什么？

首先，一切似乎都很好，因为它在Out addOrRemoveFooter中显示Toast.makeText(getApplication(),"Out"+sum2+"",Toast.LENGTH_SHORT).show();，但是当我第二次添加时会显示error。

Answer 1

首先以这种方式使用startActivityForResult开始您的活动。

private static final int RC_B = 123;
Intent intent = new Intent(ActivityA.this, ActivityB.class);    
activityA.startActivityForResult(intent, RC_B);

然后在活动B中覆盖onFinish（）和onFinish

@Override
public void finish() {
  Intent resultIntent = new Intent();
  resultIntent.putExtra("total", 45);  // For Example.
  setResult(RESULT_OK, resultIntent);
  super.finish();
}

然后在活动A中覆盖onActivityResult并输入如下代码。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)         {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == Activity.RESULT_OK && requestCode == RC_B) {
         // get your value of sum from intent
         total = intent.getIntExtra("total",0);
    }
}

Answer 2

将您的金额值存储在Sharedpreference中。每次返回活动A时，总结首选项的值。

Answer 3

使变量和静态

public static double sum =0;

而不是随时随地添加你想要的应用程序和只需在onActivityResult中显示，无需通过意图（确保在使用后重新初始化）

Answer 4

要解决加分问题，只需将=+更改为+=

即可

从OnActivityResult

4 个答案: