Question

我有一个微调器'光圈'设置了一个数字列表，一个微调器“模式”有两个选项。当按下按钮时，我需要使用各种输入运行计算，包括来自“光圈”的当前选择和来自“模式”的值。如何调用微调器的值以便在计算中使用它？

另外，如何在计算中使用微调器模式选择之前设置其他值？更具体地说，如果微调器设置为Small，那么我在计算中使用的值是0.015，而如果选择Large，我需要使用0.028

我的其他输入是EditText视图，所以现在我设置如下：

    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); 
}
}

这不是实际的等式，它只是一个测试，以确保一切正确连接。我如何调用微调器'光圈'和小/大微调器'模式'的值

Answer 1

要获取微调器的值，请根据需要调用以下任一项：

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，并将所选项目传递到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) { 

        ...

    }

您可能会选择一本基本的Java书籍并了解Java的工作范围。

Answer 2

为什么不以编程方式使用已知类型的对象填充ArrayAdapter并使用它。我写了一个类似性质的教程（链接在底部），这样做。基本前提是创建一个Java对象数组，告诉微调器，然后直接从spinner类中使用这些对象。在我的例子中，我有一个表示“状态”的对象，其定义如下：

包com.katr.spinnerdemo;

公共类州{

// 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();

现在你有一个很好的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 ) 
{ 
}

您可以在此处找到整个教程： http://www.katr.com/article_android_spinner01.php

Answer 3

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();

}

如果其他任何对象都说人。

然后

if(item != null) {

Person SelectedString = (Person) item;

}

调用微调器的值？另外，根据微调器的值使用其他值

3 个答案: