Question

当我在OnClickListener中访问我的变量时，它显示错误。

这是一段代码：

 EditText hight=(EditText)findViewById(R.id.hight);
        EditText wight=(EditText)findViewById(R.id.wight);
        Button calc=(Button) findViewById(R.id.calculate);
        TextView result=(TextView) findViewById(R.id.result);

        calc.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Double h=Double.valueOf(hight.getText().toString());
                Double w=Double.valueOf(wight.getText().toString());

                h=h/100;

Answer 1

如果您想在内部类中使用它们，那么您尝试访问的变量只需要标记为final。

        final EditText hight=(EditText)findViewById(R.id.hight);
        final EditText wight=(EditText)findViewById(R.id.wight);
        final Button calc=(Button) findViewById(R.id.calculate);
        final TextView result=(TextView) findViewById(R.id.result);

        calc.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Double h=Double.valueOf(hight.getText().toString());
                Double w=Double.valueOf(wight.getText().toString());

                h=h/100;

Answer 2

试试这个：

  final EditText hight,wight;
  final   Button calc;
  final   TextView result;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        hight=(EditText)findViewById(R.id.hight);
        wight=(EditText)findViewById(R.id.wight);
        calc=(Button) findViewById(R.id.calculate);
        result=(TextView) findViewById(R.id.result);

        calc.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Double h=Double.valueOf(hight.getText().toString());
                Double w=Double.valueOf(wight.getText().toString());

                h=h/100;

Answer 3

final EditText hight=(EditText)findViewById(R.id.hight);
final     EditText wight=(EditText)findViewById(R.id.wight);

 Button calc=(Button) findViewById(R.id.calculate);
        TextView result=(TextView) findViewById(R.id.result);

无论您要在内部课程中访问什么，您都必须将这些项目声明为最终项目。

从内部类中访问的变量

3 个答案: