“看看这个，我相信你会喜欢的。”

log_in.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        username=user_name.getText().toString();
        password=pass_word.getText().toString();
        if(username.equals(""))
        {
            user_name.setError("Enter username");
        }
        else if(password.equals(""))
        {
            pass_word.setError("Enter your password");
        }
        else
        {
            Intent intent=new Intent(MainActivity.this,Scan_QRActivity.class);
            startActivity(intent);
        }
    }
});

private boolean hasContent(EditText et) {
       return (et.getText().toString().trim().length() > 0);
}

尝试使用If ELSE If条件。您可以轻松地验证editText字段。

 if(TextUtils.isEmpty(username)) {
                userNameView.setError("User Name Is Essential");
                return;
         } else  if(TextUtils.isEmpty(phone)) {
                phoneView.setError("Please Enter Your Phone Number");
                return;
            }

试试这个:

EditText txtUserName = (EditText) findViewById(R.id.txtUsername);
String strUserName = usernameEditText.getText().toString();
if (strUserName.trim().equals("")) {
    Toast.makeText(this, "plz enter your name ", Toast.LENGTH_SHORT).show();
    return;
}

或者像这样使用TextUtils类:

if(TextUtils.isEmpty(strUserName)) {
    Toast.makeText(this, "plz enter your name ", Toast.LENGTH_SHORT).show();
    return;
}

EditText edt=(EditText)findViewById(R.id.Edt);

String data=edt.getText().toString();

if(data=="" || data==null){

 Log.e("edit text is null?","yes");

}

else {

 Log.e("edit text is null?","no");

}

对所有五个编辑文本都这样做吗

我使用这个方法，使用trim()来避免空格:

EditText myEditText = (EditText) findViewById(R.id.editUsername);
if ("".equals(myEditText.getText().toString().trim()) {
    Toast.makeText(this, "You did not enter a value!", Toast.LENGTH_LONG).show();
    return;
}

一个例子，如果你有几个EditText´

if (("".equals(edtUser.getText().toString().trim()) || "".equals(edtPassword.getText().toString().trim()))){
        Toast.makeText(this, "a value is missing!", Toast.LENGTH_LONG).show();
        return;
}