Android手机应用程序闪退

Question

自己是Android初学新手，按照课本上的示例敲代码，结果安装程序成功后，打开其闪退。。。问了好多次度娘，还是没有着落，还请各位前辈帮帮小弟，不胜感激。。。

Answer 1

代码如下，还请各位前辈帮帮我。。。
package com.example.myfirstapplycation;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import android.view.View.OnClickListener;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {
private TextView showView=null;
private TextView note=null;
private EditText editNum1=null;
private EditText editNum2=null;
private Button butadd=null;
private Button butsub=null;
private Button butmul=null;
private Button butdiv=null;
private int num1=0;
private int num2=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.showView=(TextView)super.findViewById(R.id.mytext);
this.editNum1=(EditText)super.findViewById(R.id.myeda);
this.editNum2=(EditText)super.findViewById(R.id.myedb);
this.butadd=(Button)super.findViewById(R.id.mybutadd);
this.butsub=(Button)super.findViewById(R.id.mybutsub);
this.butmul=(Button)super.findViewById(R.id.mybutmul);
this.butdiv=(Button)super.findViewById(R.id.mybutdiv);
this.note=(TextView)super.findViewById(R.id.note);
this.butadd.setOnClickListener(new AddListener());
this.butsub.setOnClickListener(new SubListener());
this.butmul.setOnClickListener(new MulListener());
this.butdiv.setOnClickListener(new DivListener());
this.editNum1.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v){
MainActivity.this.editNum1.setText("");
}
});
this.editNum2.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v){
MainActivity.this.editNum2.setText("");
}
});
}
private class AddListener implements OnClickListener{
public void onClick(View v){
MainActivity.this.num1=Integer.parseInt(MainActivity.this.editNum1.getText().toString());
MainActivity.this.num2=Integer.parseInt(MainActivity.this.editNum2.getText().toString());
MainActivity.this.note.setText("+");
MainActivity.this.showView.setText(String.valueOf(num1+num2));}
}
private class SubListener implements OnClickListener{
public void onClick(View v){
MainActivity.this.num1=Integer.parseInt(MainActivity.this.editNum1.getText().toString());
MainActivity.this.num2=Integer.parseInt(MainActivity.this.editNum2.getText().toString());
MainActivity.this.note.setText("-");
MainActivity.this.showView.setText(String.valueOf(num1-num2));}
}
private class MulListener implements OnClickListener{
public void onClick(View v){
MainActivity.this.num1=Integer.parseInt(MainActivity.this.editNum1.getText().toString());
MainActivity.this.num2=Integer.parseInt(MainActivity.this.editNum2.getText().toString());
MainActivity.this.note.setText("*");
MainActivity.this.showView.setText(String.valueOf(num1*num2));}
}
private class DivListener implements OnClickListener{
public void onClick(View v){
MainActivity.this.num1=Integer.parseInt(MainActivity.this.editNum1.getText().toString());
MainActivity.this.num2=Integer.parseInt(MainActivity.this.editNum2.getText().toString());
MainActivity.this.note.setText("/");
MainActivity.this.showView.setText(String.valueOf(num1/num2));}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}