Question

我正在创建一个包含用户名和密码作为必填字段的登录页面。如果这些必填字段为空，则应抛出错误消息“用户名和密码为空”。但是根据以下代码没有任何反应。

以下是我的代码

public class Login_testingActivity extends Activity{
EditText edit1,edit2;

/** Called when the activity is first created. */

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    EditText edit1 = (EditText) findViewById(R.id.editText_username);
    EditText edit2 = (EditText) findViewById(R.id.editText_password);

    if (edit1.getText().length() != 0 && edit2.getText().length() != 0) {
        fun();
    } else {
        Toast.makeText(Login_testingActivity.this, "You need to enter a high AND low.", Toast.LENGTH_SHORT);
    }
}
     public boolean fun(){

        Button next = (Button) findViewById(R.id.button_login);
        next.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                Intent myIntent = new Intent(view.getContext(), Login_2.class);
                startActivityForResult(myIntent, 0);
            }
        });

        return true;
   }
}

Answer 1

 Toast.makeText(Login_testingActivity.this, "You need to enter a high AND low.", Toast.LENGTH_SHORT).show();

Answer 2

首先这一行if (edit1.getText().trim().length() != 0 && edit2.getText().trim().length() != 0) {

添加onClick(View view)并检查if(){startActivty(...);}else{Toast here..}

Answer 3

尝试这样，

if (edit1.getText().equalsIgnoreCase("") && edit2.getText().equalsIgnoreCase(""))
    {
         Toast.makeText(Login_testingActivity.this, "You need to enter a high AND low.", Toast.LENGTH_SHORT).show();
    } 
  else 
    {
         fun();

    }

Answer 4

我希望这对你有用。

if (!edit1.getText().equals("") && !edit2.getText().equals("")) {
    fun();
} else {
    Toast.makeText(Login_testingActivity.this, "You need to enter a high AND low.", Toast.LENGTH_SHORT).show();
}

Answer 5

将此行用作

if (edit1.getText().toString().length() > 0 && edit2.getText().toString().length() > 0) {
        fun();
    } else {
        Toast.makeText(Login_testingActivity.this, "You need to enter a high AND low.", Toast.LENGTH_SHORT).show();
    }

将textbox检查为null或不是java android

5 个答案: