当有两个单选组时检查单选按钮 ID

Question

I am a beginner in Android programming, and trying to create a simple program that converts inches to feet, and US dollars to Japanese Yen. I have the following two radio groups in my main_activity.xml file:

 <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/distanceInput"
        android:layout_below="@+id/distanceInput"
        android:layout_marginTop="10dp" >

        <RadioButton
            android:id="@+id/inch"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="12dp"
            android:checked="true"
            android:onClick="handleClickOne"
            android:text="Inches" />

        <RadioButton
        android:id="@+id/foot"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/currencyInput"
        android:layout_below="@+id/radioGroup1"
        android:onClick="handleClickOne"
        android:text="Feet" />

    </RadioGroup>

    <RadioGroup
        android:id="@+id/radioGroup2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/currencyInput"
        android:layout_below="@+id/currencyInput"
        android:layout_marginTop="10dp" >

        <RadioButton
            android:id="@+id/japan"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/radioGroup2"
            android:layout_centerVertical="true"
            android:checked="true"
            android:text="JPY" 
            android:onClick="handleClickTwo"
            />

        <RadioButton
            android:id="@+id/usdollar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/euro"
            android:layout_below="@+id/euro"
            android:text="US Dollars" 
            android:onClick="handleClickTwo"
            />
    </RadioGroup>

This following code is for my handleClickOne() method that checks which radio button is selected between Inches and Feet, but the switch-case loop always falls on the default case - I wonder why:

public void handleClickOne(View view) {
    DecimalFormat df = new DecimalFormat("#.##");


    boolean checked = ((RadioButton) view).isChecked();

    EditText distance = (EditText) findViewById(R.id.distanceInput);
    double distanceInput = parseStringToDouble(distance.getText().toString());

    switch(view.getId()) { 
    case R.id.foot:
        // convert inches to feet
        if (checked) {
            distance.setText(df.format(inchToFoot(distanceInput)));
        }
        break;

    case R.id.inch:
        //convert feet to inches
        if (checked) {
            distance.setText(df.format(footToInch(distanceInput)));
        }
        break;

    default:  
        distance.setText("000");
        break;
    }
}

My question is whether I need to select a radio button in a radio group? and if so how?

Answer 1

Use

RadioGroup.setOnCheckedChangeListener 

rather than onclick to see which radio button is set. I dont think onclick works reliably for radiobutton

Answer 2

I'm not sure if this is the best way to do, but the following works for now:

Because I know which click handler method works for which radio group, so in each of my click handler methods (in this case handleClickOne() ), I get the radioGroup object first:

RadioGroup radioGroup1 = (RadioGroup) findViewById(R.id.radioGroup1);

then do my switch-case in this way:

switch(radioGroup1.getCheckedRadioButtonId()) { 
        case R.id.foot:
        // convert inches to feet
        if (checked) {
            distance.setText(df.format(inchToFoot(distanceInput)));
        }
        break;

    case R.id.inch:
        //convert feet to inches
        if (checked) {
            distance.setText(df.format(footToInch(distanceInput)));
        }
        break;

    default:
            distance.setText("error");
            break;
}

It works for now, but I'm still interested in learning the best practice. Thanks to all