android - 如何检查edittext是否为空？

Question

我有一个注册表单，要求用户输入用户名和密码两次，我不想提交表单并在用户填写任何字段时发出警告，但按钮不是在所有情况下都有效，这是我的代码:

user = (EditText) this.findViewById(R.id.username);
pass = (EditText) this.findViewById(R.id.password);
pass2 = (EditText) this.findViewById(R.id.password2);

u = user.getText().toString();
p1 = pass.getText().toString();
p2 = pass2.getText().toString();

if(!(u.equals("")||p1.equals("")||p2.equals(""))){
    btn = (Button) this.findViewById(R.id.register2);

    btn.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(!p1.equals(p2))
                Toast.makeText(getApplicationContext(), "Passwords didn't match!", Toast.LENGTH_SHORT).show();
            else
                Toast.makeText(getApplicationContext(), "Passwords match!", Toast.LENGTH_SHORT).show();

            }
    });
}

Answer 1

删除这个 if 条件行

if(!(u.equals("")||p1.equals("")||p2.equals(""))){

并将其放入点击监听器中

if(!(u.equals("")||p1.equals("")||p2.equals(""))){
 //Toast message please enter the username or pwd
return;
}