dt1=(EditText)findViewById(R.id.password); 
  cb1=(CheckBox)findViewById(R.id.checkbox_1); 
cb1.setOnCheckedChangeListener(new OnCheckedChangeListener() { 
   
  @Override 
  public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
    // TODO Auto-generated method stub 
    if(cb1.isChecked()){ 
       
      dt1.setTransformationMethod(HideReturnsTransformationMethod.getInstance()); //如果被选中则显示密码 
      dt1.setSelection(dt1.getText().length());   //TextView默认光标在最左端，这里控制光标在最右端 
       
    }else { 
       
      dt1.setTransformationMethod(PasswordTransformationMethod.getInstance()); //如果没选中CheckBox则隐藏密码 

    dt1.setSelection(dt1.getText().length()); 
  } 
} 
);