Android Application Force关闭错误

Question

我写了下面的代码并编译了它,但是当我运行应用程序时,我得到错误android应用程序已经意外停止强制关闭eclipse.我认为这是因为我没有初始化Button和TextView对象,但是当我初始化它们时,我会丢失令牌";" 错误.这个错误的原因是什么？

package com.umer.first.project;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class StartingPoint extends Activity {

int counter;
TextView display;
Button add, sub;
//add= new Button(this);
//sub=new Button(this);
//display=new TextView();
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_starting_point);

    add= (Button) findViewById(R.id.aButton);
    sub = (Button) findViewById(R.id.sButton);
    display= (Button) findViewById(R.id.tvButton);

    add.setOnClickListener(new View.OnClickListener() {

        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            counter++;
            display.setText("The total is " + counter);
        }
    });

    sub.setOnClickListener(new View.OnClickListener() {

        public void onClick(View arg0) {
            // TODO Auto-generated method stub

            counter--;
            display.setText("You counter is " + counter);

        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_starting_point, menu);
    return true;
}
}

Answer 1

Display是一个TextView,你不能把它投到一个按钮.

display= (Button) findViewById(R.id.tvButton);