微调如果字符串** ==不工作 [英] spinner If Strings** == not working

问题描述

这是为什么不工作？！

if(itemx == "Test number item 0")
    {
    Log.i("Dropdown", "inside if");
    us_lo_ans_hold.setText("0x");
    }; 

如果itemx是一个字符串，它有字符串测试号项目0'。

if itemx is a String and it has the string 'Test number item 0'.

我创建我的第一次微调。

I am creating my first spinner.

下面是活动的OnCreate块内的微调code：

Here is the spinner code within the onCreate block of the Activity:

    Spinner us_lo_spinner = (Spinner) findViewById(R.id.ul_ans_spinner); 
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource( this, R.array.test_defaults , android.R.layout.simple_spinner_item); 
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    us_lo_spinner.setAdapter(adapter); 

 // Spinner click listener 
us_lo_spinner.setOnItemSelectedListener(this);

下面是在strings.xml中的String数组：

Here is the String array in the strings.xml:

<string name="spin_title_ulover_ans">Spinner default:</string> 
<string-array name="test_defaults"> 
    <item>Test number item 0</item>
    <item>Test number item 1</item> 
    <item>Test number item 2</item> 
    <item>Test number item 3</item> 
    <item>Test number item 4</item> 
</string-array>

下面是onItemSelected：

Here is the onItemSelected:

public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) 
{
    Log.i("XXX_Dropdown", "XXXX");
    TextView us_lo_ans_hold = (TextView)findViewById(R.id.us_lo_ans_holdtest);
    // On selecting a spinner item 
    String itemx = arg0.getSelectedItem().toString();
    us_lo_ans_hold.setText("oppp12");
    Log.i("Dropdown", "item: " + itemx);
    Log.i("Dropdown", "arg1: " + arg1);
    Log.i("Dropdown", "arg2: " + arg2);
    Log.i("Dropdown", "arg3: " + arg3);
    // Showing selected spinner item 
    if(itemx == "Test number item 0")
        {
        Log.i("Dropdown", "inside if");
        us_lo_ans_hold.setText("0x");
        }; 

}

这是所有Log.i（，）■我把我能告诉itemx是正确的，它具有正确的字符串时，在微调的项目被选中。 然而，如果将无法正常工作。

From all the Log.i(,)s I put in I can tell the itemx is correct, it has the correct string when an item in the spinner is selected. Yet the IF will not work.

如果我将如果以这样的：

If I change the IF to this:

if(arg2 == 0)
    {
    Log.i("Dropdown", "inside if");
    us_lo_ans_hold.setText("0x");
    }; 

将工作;但是，这不是我想要的！

it will work; BUT that is not what I want!

所以......这是为什么不工作？！

So... why is this not working ?!:

if(itemx == "Test number item 0")
    {
    Log.i("Dropdown", "inside if");
    us_lo_ans_hold.setText("0x");
    }; 

如果itemx是一个字符串，它有字符串测试数项0。 ？

if itemx is a String and it has the string 'Test number item 0'. ?

还如何或何时会onNothingSelected被称为？ 当你点击后退按钮？ 当您选择该项目已被选中？ 我的onNothingSelected永远不会被调用！

also how or when would 'onNothingSelected' be called? When you hit the back button ? When you select the item already selected? My 'onNothingSelected' is never called !

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
    Log.i("Dropdown", "in NOTHING SELECTED");
    TextView us_lo_ans_hold = (TextView)findViewById(R.id.us_lo_ans_holdtest);
    us_lo_ans_hold.setText("nothing selected");
}

试图把在这样的活动的onCreate块：

Tried putting in the onCreate block of the Activity like the:

    // Spinner click listener 
    us_lo_spinner.setOnItemSelectedListener(this);

us_lo_spinner.onNothingSelected(this)   

但〜编译〜确实如此。

but the ~compiler~ does like that.

所以...如何或何时被onNothingSelected打来电话，它是如何迷上了一个微调？

So... how or when is 'onNothingSelected' called and how is it hooked up to a spinner ?

推荐答案

如果你的 itemx 是一个变量，那么你不能比较两个字符串 = = 。使用而不是 items.equals（测试号项目0）;

If your itemx is a variable then you cant compare two strings with ==. Use instead items.equals("Test number item 0");

== 比较的对象和等于（）比较两个字符串值。 看看一本帖子。

== compares objects and equals() compare string values. Take a look a this post.

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