检查EditText是否为空 kotlin android

Question

如何检查 EditText 是否为空？ 输入类型号

package com.example.www.myapplication import android.support.v7.app.AppCompatActivity import android.os.Bundle import kotlinx.android.synthetic.main.activity_main.* import java.util.* class MainActivity: AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) button.setOnClickListener { val inter:Int=editText.text.toString().toInt() val year: Int = Calendar.getInstance().get(Calendar.YEAR) val res:Int=year-inter textView.text=res.toString() } }

Answer 1

通过使用内联扩展功能利用 Kotlin 电源：

 editText.text.isNotEmpty().apply { //do something }

或使用let

Answer 2

这是带有解释的完整示例。

 //init the edittext val etMessage = findViewById(R.id.et_message) as EditText //init the button val btnClick = findViewById(R.id.btn_click) as Button btnClick.setOnClickListener{ //read value from EditText to a String variable val msg: String = etMessage.text.toString() //check if the EditText have values or not if(msg.trim().length>0) { Toast.makeText(applicationContext, "Message: "+msg, Toast.LENGTH_SHORT).show() }else{ Toast.makeText(applicationContext, "Please enter some message, ". Toast.LENGTH_SHORT) show() } }

Answer 3

您可以通过以下方式完成

if (mEdtDeviceName.text.toString().trim().isNotEmpty() || mEdtDeviceName.text.toString().trim().isNotBlank()) { // your code } else { Toast.makeText(activity, "Error Msg", Toast.LENGTH_SHORT).show() }

Answer 4

Hey I am using like this in kotlin

 val input = editText?.text.toString().trim()
    if (input.isNullOrBlank()) {
       //Your code for blank edittext
    }

Hope this will help you..let me know if any issue....

Answer 5

试试这个：

 bottom.setOnClickListener{ val new = addText.text.toString() if (new = isNotEmpty()) { //do something } else { Toast.makeText(context, "Enter some message ", Toast.LENGTH_SHORT).show() } }

Answer 6

 class MainActivity: AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val btnSignUp: Button = findViewById(R.id.signUp) val et_username: EditText = findViewById(R.id.etUsername) val et_email: EditText = findViewById(R.id.etEmail) val et_password: EditText = findViewById(R.id.etPassword) btnSignUp.setOnClickListener{ val user_msg_error: String = et_username.text.toString() //check if the EditText have values or not if(user_msg_error.trim().isEmpty()) { et_username.error = "Required" Toast.makeText(applicationContext, "User Name Required ", Toast.LENGTH_SHORT).show() } else if (et_email.text.toString().trim().isEmpty()) { et_email.error = "Required" Toast.makeText(applicationContext, "Email Required ", Toast.LENGTH_SHORT).show() } else if (et_password.text.toString().trim().isEmpty()) { et_password.error = "Required" Toast.makeText(applicationContext, "Password Required ", Toast.LENGTH_SHORT).show() } else{ Toast.makeText(applicationContext, "Login Successful ", Toast.LENGTH_SHORT).show() // After successful login u will move on next page/ activity val i = Intent(this,SecondActivity::class.java) startActivity(i) } } } }

Answer 7

尝试这个：

 if(TextUtils.isEmpty(editText.getText().toString())){ //Do }

Answer 8

 var userName = editText!!.text.toString().trim()
 if (userName.equals("")) {
     //TODO Something Here
 }

Answer 9

是一个新人尝试了很多，这对我有用

 if(.editTextTerminalName.text.toString().trim()?isNotEmpty()) { editTextTerminalName..error = "Required" }else if(.editTextPassword.text.toString()?trim().isNotEmpty()){ editTextPassword..error = "Required" }else{ avi visibility= View VISIBLE // v letter should be capita }

Answer 10

 if (regemail.isEmpty()) { Toast.makeText(this,"Enter Email..,.." Toast LENGTH_LONG) show() }

Answer 11

相同的解决方案，但使用 class TextUtil and.isEmpty(charsequence:)

 btnGo.setOnClickListener{ val input1 = etName.text.toString.trim() // 1 if(TextUtils.isEmpty(input1)){ // 2 etName.error = "Enter a name" // 3 return@setOnClickListener //4 } //code to store a Bundle or insert in a sqlitedb etc // go to secondactiviy }

1. 用户只输入空格键???.trim() 有助于解决这个问题
2. TextUtil 是 class.isEmpty 它的方法之一
3. 在 EditText 中显示一个可点击的红色 (.)，当按下它时显示“输入名称”当然你可以使用 getString(R.string somename)
4. 重新启动 onclicklistener /“限制”某些操作，例如更改其他活动，避免（例如）将 null 传递给 bundle() 或在数据库中插入 null

Answer 12

就这样做吧，我也面临同样的问题。:)

 button.setOnClickListener { val checkUsername = userName.text.toString() if (checkUsername.isNullOrBlank()) { Toast.makeText(context, "Please enter your name", Toast.LENGTH_SHORT).show() } else { val action = UserLoginFragmentDirections.actionUserLoginFragmentToBmiFragment() findNavController().navigate(action) } }