Android，两个互相影响的EditText如何避免死循环

简单来说，是一个类似如下的需求：

两个EditText，假设名字分别是 et1和et2;et1的值*一个数字，假设是4500=et2的值；

当 et1 的值发生变化时，et2 的值也发生变化，et2的值发生变化时，et1的值也发生变化，

用过用简单的 TextWatcher 就会发生死循环，如何避免，下面是这个例子代码的最核心部分，简单来说就是在一个事件起效果时，另外一个事件注销。

private int v1
private EditText et1, et2;
 
private TextWatcher tw1, tw2;
 
/** Called when the activity is first created. */
@Override
public void
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
 
 
    et1 = (EditText) findViewById(R.id.editText1);
    et2 = (EditText) findViewById(R.id.editText2);
    et1.setText("3");
    et2.setText("13500");
 
    tw1 = new
 
    @Override
    public void onTextChanged(CharSequence s, int start, int before,int
        et2.removeTextChangedListener(tw2);
        int
        try
            et1val =Integer.parseInt(s.toString());
        } catch
            et1val = 0;
        }
        Log.i("eee1", ""+et1val);
 
        int et2val = et1val * v1;
        et2.setText(""
    }
 
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,int
        }
 
    @Override
    public void
        et2.addTextChangedListener(tw2);
    }
    };

    tw2 = new
 
    @Override
    public void onTextChanged(CharSequence s, int start, int before,int
        et1.removeTextChangedListener(tw1);
        int
        try
            et2val = Integer.parseInt(s.toString());
        } catch
            et2val = 0;
        }
        Log.i("eee2", ""+et2val);
 
 
        int et1val = et2val / v1;
        et1.setText(""
    }
 
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,int
    }
 
    @Override
    public void
        et1.addTextChangedListener(tw1);
    }
    };
 
    et1.addTextChangedListener(tw1);
    et2.addTextChangedListener(tw2);
 
 
 
}