Android 使用布尔标志来定义用户输入

Question

如果此处的语法不正确，我深表歉意，尤其是关于布尔值：

public class WeightConverter extends Activity implements OnClickListener, OnCheckedChangeListener {
    Button convertWeight;
    TextView conversionResults;
    EditText enterWeight;
    RadioGroup weightPicker;
    RadioButton radKG, radLB;
    double weightValue, convertedWeight;
    String weightString;
    String measurement;
    Boolean weightSwitch;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.weightconverter);
        initializeVariables();
        weightSwitch = false;
        radKG.setChecked(true);
    }

    private void initializeVariables() {
        convertWeight = (Button) findViewById(R.id.btnConvertWeight);
        conversionResults =(TextView) findViewById(R.id.tvWeightConversion);
        enterWeight =(EditText) findViewById(R.id.etWeightToConvert);
        weightPicker = (RadioGroup) findViewById(R.id.rgWeightType);
        radKG = (RadioButton) findViewById(R.id.radKG);
        radLB = (RadioButton) findViewById(R.id.radLB);
        convertWeight.setOnClickListener(this);
        weightPicker.setOnCheckedChangeListener(this);


    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {

        case R.id.btnConvertWeight:

            if (weightSwitch = true){
                convertedWeight = weightValue /2.2;
                measurement = "Kilograms";
            }else{
                convertedWeight = weightValue *2.2;
                measurement = "Pounds";
            }


            conversionResults.setText(weightValue + " = " + String.valueOf(convertedWeight) + " " + measurement);
            break;
        }

    }

    @Override

    public void onCheckedChanged(RadioGroup group, int checkedId) {
        weightValue = Double.parseDouble(enterWeight.getText().toString());
        switch (checkedId) {

        case R.id.radKG:

            weightSwitch = true;

            break;
        case R.id.radLB:

            weightSwitch = false;

            break;

        }
    }



}

根据用户是否选择任一布尔类型，应执行不同的计算，但是只有转换为磅才有效..

Answer 1

您正在尝试将 boolean 值与此行中的 = 运算符进行比较：

if (weightSwitch = true){

但是=是赋值运算符，所以weightSwitch总是true。

使用== 比较boolean 值，或更好：

if (weightSwitch)

因为它已经是一个boolean 值。