正在编写一个简单的计算器,按钮点击出现问题,详情见下!请指教

Question

点击按钮后无法在TextView中显示出对应的内容.
源码如下:
package com.example.xingpengfei.calculator;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

private TextView inputnum;
private Button button0;
private Button button1;
private Button button2;
private Button button3;
private Button button4;
private Button button5;
private Button button6;
private Button button7;
private Button button8;
private Button button9;
private Button button10;
private Button button11;
private Button button12;
private Button button13;
private Button button14;
private Button button15;
private Button button16;
private Button button17;
private  String s="";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    inputnum=(TextView)findViewById(R.id.input_num);
    button0=(Button)findViewById(R.id.button0);
    button1=(Button)findViewById(R.id.button1);
    button2=(Button)findViewById(R.id.button2);
    button3=(Button)findViewById(R.id.button3);
    button4=(Button)findViewById(R.id.button4);
    button5=(Button)findViewById(R.id.button5);
    button6=(Button)findViewById(R.id.button6);
    button7=(Button)findViewById(R.id.button7);
    button8=(Button)findViewById(R.id.button8);
    button9=(Button)findViewById(R.id.button9);
    button10=(Button)findViewById(R.id.button10);
    button11=(Button)findViewById(R.id.button11);
    button12=(Button)findViewById(R.id.button12);
    button13=(Button)findViewById(R.id.button13);
    button14=(Button)findViewById(R.id.button14);
    button15=(Button)findViewById(R.id.button15);
    button16=(Button)findViewById(R.id.button16);
    button17=(Button)findViewById(R.id.button17);
}
@Override
public void onClick(View view) {
    switch (view.getId())
    {
        case R.id.button0:
            s+=0;
            inputnum.setText(s);
            break;
        case R.id.button1:{
            s+=1;
            inputnum.setText(s);
            break;
        }
        case R.id.button2:
            s+=2;
            inputnum.setText(s);
            break;
        case R.id.button3:
            s+=3;
            inputnum.setText(s);
            break;
        case R.id.button4:
            s+=4;
            inputnum.setText(s);
            break;
        case R.id.button5:
            s+=5;
            inputnum.setText(s);
            break;
        case R.id.button6:
            s+=6;
            inputnum.setText(s);
            break;
        case R.id.button7:
            s+=7;
            inputnum.setText(s);
            break;
        case R.id.button8:
            s+=8;
            inputnum.setText(s);
            break;
        case R.id.button9:
            s+=9;
            inputnum.setText(s);
            break;
        case R.id.button10:
            s+="+";
            inputnum.setText(s);
            break;
        case R.id.button11:
            s+="-";
            inputnum.setText(s);
            break;
        case R.id.button12:
            s+="*";
            inputnum.setText(s);
            break;
        case R.id.button13:
            s+="÷";
            inputnum.setText(s);
            break;
        case R.id.button14:
            s+=".";
            inputnum.setText(s);
            break;
        case R.id.button15:
            //start
            inputnum.setText("");
            break;
        case R.id.button16:    //delete

            inputnum.setText("");
            break;
        case R.id.button17:  //=

            inputnum.setText("");
            break;

    }
}

}

Answer 1

虽然你的Activity去实现了OnClickListener接口但是你还需要去指定每个button的点击事件：
button.setOnclickListener(this)