Android onClick方法错误

Question

我试图在Android中做一个简单的计算器。

public class MainActivity extends Activity {

    Button  show_cam_ctrl,
            show_voice_ctrl,
            cal_btn_clear,
            cal_btn_del,
            cal_btn_percent,
            cal_btn_divide,
            cal_btn_plus,
            cal_btn_pi,
            cal_btn_root,
            cal_btn_dot,
            cal_btn_equal,
            cal_btn_power,
            cal_btn_ptrl,
            cal_btn_sin, cal_btn_cos, cal_btn_tan,
            cal_btn_sinIn, cal_btn_cosIn, cal_btn_tanIn,
            cal_btn_0, cal_btn_1, cal_btn_2, cal_btn_3, cal_btn_4, cal_btn_5, cal_btn_6, cal_btn_7, cal_btn_8, cal_btn_9;

    TextView ma_res_txt;

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

        //Control Buttons
        show_cam_ctrl = (Button) findViewById(R.id.show_cam_ctrl);
        show_voice_ctrl = (Button) findViewById(R.id.show_voice_ctrl);

        show_cam_ctrl.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent i = new Intent(MainActivity.this,cam_calculator.class);
                startActivity(i);
            }
        });
        show_voice_ctrl.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent i = new Intent(MainActivity.this,voice_calculator.class);
                startActivity(i);
            }
        });


    }

    //Calculator main page logic

    public void calculate(View v){

        ma_res_txt = (TextView) findViewById(R.id.ma_res_txt);
        String t;
        int length = ma_res_txt.getText().length();

        switch (v.getId()){


            case R.id.cal_btn_clear:{
                ma_res_txt.setText("");
                break;
            }
            case R.id.cal_btn_del:{
                String text = ma_res_txt.getText().toString();
                ma_res_txt.setText(text.substring(0, text.length() - 1));
            }


            case R.id.cal_btn_percent:{
                t = "%";
                ma_res_txt.setText(t);
                break;
            }


        }

    }






    @Override
    public void finish() {
        super.finish();
    }




}

Answer 1

如果在onClick中添加了calculate()，请检查xml按钮代码，然后删除（）

  <Button 
   android:id="@+id/cal_btn_percent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="calculate()" />

要更改remove（）

<Button android:id="@+id/cal_btn_percent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="calculate" />