检查是否EditText.isEmpty（）不工作 [英] Checking if EditText.isEmpty() not working

问题描述

在我的code，我要检查，如果密码字段为空。我现在用的的isEmpty（）方法来实现它，但它不工作。离开密码领域的空白，将恢复到第二否则-if语句，而不是第三。结果

 公共类MainActivity延伸活动{
@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.activity_main）;    最终的EditText密码=（EditText上）findViewById（R.id.editText_Password）;
    按钮输入=（按钮）findViewById（R.id.button）;    enter.setOnClickListener（新OnClickListener（）{        @覆盖
        公共无效的onClick（查看为arg0）{            串user_pass;
            。user_pass = password.getText（）的toString（）;                如果（user_pass.equals（123））{
                    Toast.makeText（MainActivity.this，欢迎光临！，Toast.LENGTH_SHORT）.show（）;
                    意图I =新意图（com.mavenmaverick.password.OKActivity）;
                    startActivity（Ⅰ）;
                }                其他                    如果（user_pass！=123）{
                    Toast.makeText（MainActivity.this，不正确的，Toast.LENGTH_SHORT）.show（）;
                    AlertDialog.Builder dialogBu​​ilder =新AlertDialog.Builder（MainActivity.this）;
                        dialogBu​​ilder.setIcon（R.drawable.ic_launcher）;
                        dialogBu​​ilder.setTitle（哎呀！）;
                        dialogBu​​ilder.setMessage（密码不正确）;
                        dialogBu​​ilder.setPositiveButton（OK，NULL）;
                        dialogBu​​ilder.show（）;
                    }                其他
                    如果（user_pass.isEmpty（））{
                        AlertDialog.Builder dialogBu​​ilder =新AlertDialog.Builder（MainActivity.this）;
                            dialogBu​​ilder.setIcon（R.drawable.ic_launcher）;
                            dialogBu​​ilder.setTitle（哎呀！）;
                            dialogBu​​ilder.setMessage（密码字段不能为空）;
                            dialogBu​​ilder.setPositiveButton（OK，NULL）;
                            dialogBu​​ilder.show（）;
                        }        }
    }）;
}
 

解决方案

您如果第二次检查 user_pass！=123。从逻辑上讲，如果 user_pass 是空它不是123，它甚至不会去的第三个如果。如果你想要的工作，你切换第二和第三个如果。

In my code, I want to check if the password field is empty. I am using the isEmpty() method to accomplish it but it does not work. Leaving the password field blank, reverts to the 2nd else-if statement and not the third.

public class MainActivity extends Activity {


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final EditText password = (EditText) findViewById(R.id.editText_Password);
    Button enter = (Button) findViewById(R.id.button);

    enter.setOnClickListener(new OnClickListener() {



        @Override
        public void onClick(View arg0) {

            String user_pass;
            user_pass = password.getText().toString();

                if (user_pass.equals("123")) {
                    Toast.makeText(MainActivity.this, "Welcome!", Toast.LENGTH_SHORT).show();
                    Intent I = new Intent("com.mavenmaverick.password.OKActivity");
                    startActivity(I);
                }

                else

                    if(user_pass != "123"){
                    Toast.makeText(MainActivity.this, "Incorrect", Toast.LENGTH_SHORT).show();
                    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
                        dialogBuilder.setIcon(R.drawable.ic_launcher);
                        dialogBuilder.setTitle("Oops!");
                        dialogBuilder.setMessage("Incorrect Password");
                        dialogBuilder.setPositiveButton("OK", null);
                        dialogBuilder.show();
                    }

                else
                    if (user_pass.isEmpty()) {
                        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(MainActivity.this);
                            dialogBuilder.setIcon(R.drawable.ic_launcher);
                            dialogBuilder.setTitle("Oops!");
                            dialogBuilder.setMessage("Password Field Cannot Be Empty");
                            dialogBuilder.setPositiveButton("OK", null);
                            dialogBuilder.show();
                        }

        }
    });




}

解决方案

Your second if checks for user_pass != "123". Logically, if the user_pass is empty it is not "123" and it won't even go for the third if. If you want it to work, switch your second and third if.

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