putExtras多个putString不工作 [英] putExtras multiple putString not working

问题描述

我需要从一个activitiy传递2个变量到另一个活动。

I need to pass 2 variables from one activitiy to another activity.

我的第一个活动如下：

@Override 
public boolean onContextItemSelected(MenuItem item) { 
    Bundle bundle=new Bundle();
switch (item.getItemId()){ 

case 1: 

    bundle.putString(drinkButton, "4");
    bundle.putString(drinkType, "1");
    Intent myIntent1 = new Intent(this, DrinksList.class);
    myIntent1.putExtras(bundle);
    startActivityForResult(myIntent1, 0);
    return true;

case 2: 

    bundle.putString(drinkButton, "1");
    bundle.putString(drinkType, "2");
    Intent myIntent2 = new Intent(this, DrinksList.class);
    myIntent2.putExtras(bundle);
    startActivityForResult(myIntent2, 0);
    return true;
}
return false;

然后在我使用它来获取值回来了，但两个值，即相同的一样drinkType案例1我得到的第二个活动1这两个病例2我得到2既当我希望得到4,1和1,2。

Then in the second activity i use this to get the values back, but both values are the same i.e. the same as 'drinkType' case 1 I get "1" for both and case 2 I get "2" for both when I expect to get 4,1 and 1,2.

Bundle extras = getIntent().getExtras();

        drinkButton = extras.getString(drinkButton);


        drinkType = extras.getString(drinkType);

    Toast.makeText(this, "drink Button = "+drinkButton+"  Drink Type = "+drinkType, Toast.LENGTH_LONG).show();  


} 

我似乎无法通过一个以上的额外费用。任何想法？

It seems I can't pass more than one extra. Any ideas?

推荐答案

如果你不赋值给变量 drinkBut​​ton 和 drinkType ，他们都空当你在第一个活动中使用它们。在这种情况下，你的code：

If you don't assign values to the variables drinkButton and drinkType, they're both null when you use them in the first activity. In that case, your code:

bundle.putString(drinkButton, "4");
bundle.putString(drinkType, "1");

等同于

bundle.putString(null, "4");
bundle.putString(null, "1");

你看，你使用的是与空值作为钥匙的说法变量 putString（）。

See, you're using variables with null value as the "key" argument to putString().

要设置这样的钥匙参数的最常见的方法是使用常数。例如：

The most common way to set the "key" arguments like this is to use constants. For example:

public interface IntentConstants {
    public static final String EXTRA_DRINK_BUTTON = "DrinkButton";
    public static final String EXTRA_DRINK_TYPE = "DrinkType";
}

然后在你的活动中，使用这些常量，像这样的：

And then in your activity, use those constants, like this:

bundle.putString(IntentConstants.EXTRA_DRINK_BUTTON, "4");
bundle.putString(IntentConstants.EXTRA_DRINK_TYPE, "1");

和在第二活动检索它们

String drinkButton = extras.getString(IntentConstants.EXTRA_DRINK_BUTTON);
String drinkType = extras.getString(IntentConstants.EXTRA_DRINK_Type);

顺便说一句，有没有你传递的整数值为String额外特别的原因？为什么不将它们作为整数？

By the way, is there a particular reason that you're passing integer values as String extras? Why not pass them as integers?

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