android-demo1登陆界面数据保存

实现一个第一次登陆成功切选择保存后第二次打开默认用户名：
   protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        final EditText edit1=(EditText) findViewById(R.id.editText1);
        final EditText edit2=(EditText) findViewById(R.id.editText2);
        final CheckBox check=(CheckBox) findViewById(R.id.checkBox1);
        final SharedPreferences pre=getSharedPreferences("mypre",MODE_PRIVATE);
        final Editor editor=pre.edit();
        final Button bt=(Button) findViewById(R.id.button1);
        
        
        String name=pre.getString("username","");
        if(name==null){
        	check.setChecked(false);
        }else{
        	edit1.setText(name);
        	check.setChecked(true);
        }
        
        
        
        
        
        
        bt.setOnClickListener(new OnClickListener(){     

			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				String username=edit1.getText().toString().trim();  //trim()方法为去掉先后空白
				String password=edit2.getText().toString().trim();
				
				if("admin".equals(username)&&"123456".equals(password)){  //若是用户名或密码正确切check框为选中状态，则将用户名信息储存起来
					if(check.isChecked()){                                        
						editor.putString("username",username);
						editor.commit();
					}else{
						editor.remove(username); //不须要储存则删除
						editor.commit();
						
					}
					
				}else{
					Toast.makeText(MainActivity.this,"用户名或密码错误",Toast.LENGTH_LONG).show();
				}
				
				
				
				
			}
        	
        });