4

我有一个带有数字列表的微调器“光圈”,以及一个带有两个选项的微调器“模式”。当按下按钮时,我需要使用各种输入进行计算,包括来自“光圈”的当前选择和从“模式”派生的值。如何调用微调器的值以便在计算中使用它?

另外,在计算中实施之前,如何使用微调器'模式的选择来设置这个其他值?更具体地说,如果微调器设置为小,那么我在计算中使用的值是 0.015,而如果选择大,我需要使用 0.028

我的其他输入是 EditText 视图,所以现在我的设置如下:

    input = (EditText) findViewById(R.id.input1); 
    input2 = (EditText) findViewById(R.id.input2);
    input3 = (EditText) findViewById(R.id.input3); 
    input4 = (EditText) findViewById(R.id.input4);
    output = (TextView) findViewById(R.id.result); 
    output2 = (TextView) findViewById(R.id.result2);

    //aperture dropdown
    Spinner s = (Spinner) findViewById(R.id.apt);
    ArrayAdapter adapter2 = ArrayAdapter.createFromResource(        this, R.array.apertures,       
    android.R.layout.simple_spinner_item);
    adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    s.setAdapter(adapter2);

    //button
    final Button button = (Button) findViewById(R.id.calculate);
    button.setOnClickListener(new View.OnClickListener() {             
     public void onClick(View v) {                 
      // Perform action on click
      doCalculation();
       }         
      });
     }

private void doCalculation() { 
    // Get entered input value 
    String strValue = input.getText().toString(); 
    String strValue2 = input2.getText().toString();
    String strValue3 = input3.getText().toString(); 
    String strValue4 = input4.getText().toString();

    // Perform a hard-coded calculation 
    double imperial1 = (Double.parseDouble(strValue3) + (Double.parseDouble(strValue4) / 12));
    double number = Integer.parseInt(strValue) * 2; 
    double number2 = ((number / 20) + 3) / Integer.parseInt(strValue2);

    // Update the UI with the result 
    output.setText("Result:  "+ number); 
    output2.setText("Result2: "+ imperial1); 
}
}

这不是实际的方程式,它只是一个测试,以确保一切都正确连接。我如何称呼微调器“光圈”和小/大微调器“模式”的值

4

3 回答 3

5

要获取微调器的值,请酌情调用以下方法之一:

Object item = spinner.getSelectedItem();

long id = spinner.getSelectedItemId();

int position = getSelectedItemPosition();

View selectedView = getSelectedView();

在您的情况下,您可以将微调器声明为 final 并将所选项目传递给 doCalculations() 方法,如下所示:

    final Spinner aptSpinner = (Spinner) findViewById(R.id.apt);
    ...

    //button
    final Button button = (Button) findViewById(R.id.calculate);
    button.setOnClickListener(new View.OnClickListener() {             
     public void onClick(View v) {                 
      // Perform action on click
      doCalculation(aptSpinner.getSelectedItem());
       }         
      });
     }

    private void doCalculation(Object selectedItem) { 

        ...

    }

拿起一本基本的 Java 书籍并了解 Java 中的作用域如何工作可能对您有好处。

于 2010-01-25T03:18:51.047 回答
3

为什么不用已知类型的对象以编程方式填充您的 ArrayAdapter 并使用它。我已经写了一个类似性质的教程(底部的链接)来做到这一点。基本前提是创建一个 Java 对象数组,告诉微调器,然后直接从微调器类中使用这些对象。在我的示例中,我有一个表示“状态”的对象,其定义如下:

包 com.katr.spinnerdemo;

公共类状态{

// Okay, full acknowledgment that public members are not a good idea, however
// this is a Spinner demo not an exercise in java best practices.
public int id = 0;
public String name = "";
public String abbrev = "";

// A simple constructor for populating our member variables for this tutorial.
public State( int _id, String _name, String _abbrev )
{
    id = _id;
    name = _name;
    abbrev = _abbrev;
}

// The toString method is extremely important to making this class work with a Spinner
// (or ListView) object because this is the method called when it is trying to represent
// this object within the control.  If you do not have a toString() method, you WILL
// get an exception.
public String toString()
{
    return( name + " (" + abbrev + ")" );
}
}

然后,您可以使用这些类的数组填充微调器,如下所示:

       // Step 1: Locate our spinner control and save it to the class for convenience
    //         You could get it every time, I'm just being lazy...   :-)
    spinner = (Spinner)this.findViewById(R.id.Spinner01);

    // Step 2: Create and fill an ArrayAdapter with a bunch of "State" objects
    ArrayAdapter spinnerArrayAdapter = new ArrayAdapter(this,
          android.R.layout.simple_spinner_item, new State[] {   
                new State( 1, "Minnesota", "MN" ), 
                new State( 99, "Wisconsin", "WI" ), 
                new State( 53, "Utah", "UT" ), 
                new State( 153, "Texas", "TX" ) 
                });

    // Step 3: Tell the spinner about our adapter
    spinner.setAdapter(spinnerArrayAdapter);  

您可以按如下方式检索所选项目:

State st = (State)spinner.getSelectedItem();

现在你有一个真正的 java 类可以使用。如果要在微调器值更改时进行拦截,只需实现 OnItemSelectedListener 并添加适当的方法来处理事件。

public void onItemSelected(AdapterView<?> parent, View view, int position, long id) 
{
    // Get the currently selected State object from the spinner
    State st = (State)spinner.getSelectedItem();

    // Now do something with it.
} 

public void onNothingSelected(AdapterView<?> parent ) 
{ 
}

你可以在这里找到整个教程: http ://www.katr.com/article_android_spinner01.php

于 2010-10-30T15:16:21.760 回答
0

如果 R.array.apertures 是一个字符串数组,那么你可以使用

Object item = spinner.getSelectedItem(); 

if(item != null) {

String SelectedString = item.toString();

}

如果它的任何其他对象说人。

然后

if(item != null) {

Person SelectedString = (Person) item;

}
于 2010-10-20T18:07:31.990 回答