我是編程新手，我需要你的幫助，我在editText txt50中插入數字時遇到錯誤，應用程序崩潰請幫助我，我不知道是什么錯誤：法典：public class Main2Activity extends AppCompatActivity { private EditText cinco, cien, doscientos, quinientos, mil, dosmil, cincomil, diezmil, veintemil, cincuentamil, cienmil; private TextView diezmob; public static final String nombres = "names"; TextView txtBienvenido; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); txtBienvenido = (TextView) findViewById(R.id.txtbienvenido); String usuario = getIntent().getStringExtra("names"); txtBienvenido.setText("?Bienvenido(a) Hermano(a) " + usuario + "!"); diezmob = (TextView) findViewById(R.id.txtdiezmob); cinco = (EditText) findViewById(R.id.txt50); cien = (EditText) findViewById(R.id.txt100); doscientos = (EditText) findViewById(R.id.txt200); quinientos = (EditText) findViewById(R.id.txt500); mil = (EditText) findViewById(R.id.txt1000); dosmil = (EditText) findViewById(R.id.txt2000); cincomil = (EditText) findViewById(R.id.txt5000); diezmil = (EditText) findViewById(R.id.txt10000); veintemil = (EditText) findViewById(R.id.txt20000); cincuentamil = (EditText) findViewById(R.id.txt50000); cienmil = (EditText) findViewById(R.id.txt100000); cinco.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } }); } }日志：在編輯文本 txt50 中插入數字時出錯，應用程序崩潰：java.lang.NumberFormatexception： 無效的雙精度： “”
2 回答
慕森王
TA貢獻1777條經驗 獲得超3個贊
我用這個代碼解決這個錯誤，任何錯誤請說出來。
package com.example.josue.login;
import android.app.DatePickerDialog;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TextView;
import java.util.Calendar;
public class Main2Activity extends AppCompatActivity implements View.OnClickListener {
private TextView diezmob;
public static final String nombres = "names";
TextView txtBienvenido;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
txtBienvenido = (TextView) findViewById(R.id.txtbienvenido);
String usuario = getIntent().getStringExtra("names");
txtBienvenido.setText("?Bienvenido(a) Hermano(a) " + usuario + "!");
diezmob = (TextView) findViewById(R.id.txtdiezmob);
findViewById(R.id.btncalcular).setOnClickListener(this);
findViewById(R.id.btncalcular5).setOnClickListener(this);
findViewById(R.id.btncalcular10).setOnClickListener(this);
findViewById(R.id.btncalcular15).setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btncalcular:
double cinco, cien, doscientos, quinientos, mil, dosmil, cincomil, diezmil, veintemil, cincuentamil, cienmil;
String Cinco = ((EditText) findViewById(R.id.txt50)).getText().toString();
String Cien = ((EditText) findViewById(R.id.txt100)).getText().toString();
String Doscientos = ((EditText) findViewById(R.id.txt200)).getText().toString();
String Quinientos = ((EditText) findViewById(R.id.txt500)).getText().toString();
String Mil = ((EditText) findViewById(R.id.txt1000)).getText().toString();
String Dosmil = ((EditText) findViewById(R.id.txt2000)).getText().toString();
String Cincomil = ((EditText) findViewById(R.id.txt5000)).getText().toString();
String Diezmil = ((EditText) findViewById(R.id.txt10000)).getText().toString();
String Veintemil = ((EditText) findViewById(R.id.txt20000)).getText().toString();
String Cincuentamil = ((EditText) findViewById(R.id.txt50000)).getText().toString();
String Cienmil = ((EditText) findViewById(R.id.txt100000)).getText().toString();
if (Cinco != null && !Cinco.equals("")) {
cinco = Double.valueOf(Cinco);
}else{
cinco = 0;
}
if (Cien != null && !Cien.equals("")){
cien = Double.valueOf(Cien);
}else{
cien=0;
}
if (Doscientos != null && !Doscientos.equals("")) {
doscientos = Double.valueOf(Doscientos);
}else{
doscientos=0;
}
if (Quinientos != null && !Quinientos.equals("")) {
quinientos = Double.valueOf(Quinientos);
}else{
quinientos = 0;
}
if (Mil != null && !Mil.equals("")){
mil = Double.valueOf(Mil);
}else{
mil = 0;
}
if (Dosmil != null && !Dosmil.equals("")) {
dosmil = Double.valueOf(Dosmil);
}else {
dosmil = 0;
}
if (Cincomil != null && !Cincomil.equals("")) {
cincomil = Double.parseDouble(Cincomil);
}else {
cincomil = 0;
}
if (Diezmil !=null && !Diezmil.equals("")) {
diezmil = Double.valueOf(Diezmil);
}else {
diezmil = 0;
}
if (Veintemil != null && !Veintemil.equals("")) {
veintemil = Double.valueOf(Veintemil);
}else {
veintemil = 0;
}
if (Cincuentamil != null && !Cincuentamil.equals("") ) {
cincuentamil = Double.valueOf(Cincuentamil);
}else {
cincuentamil = 0;
}
if (Cienmil != null && !Cienmil.equals("") ) {
cienmil = Double.valueOf(Cienmil);
}else {
cienmil = 0;
}
double suma = (cinco * 50) + (cien * 100) + (doscientos * 200) + (quinientos * 500) + (mil * 1000) +
(dosmil * 2000) + (cincomil * 5000) + (diezmil * 10000) + (veintemil * 20000) + (cincuentamil * 50000) +
(cienmil * 100000);
String resultado = String.valueOf((int)(suma));
diezmob.setText(String.valueOf(resultado));
break;
case R.id.btncalcular5:
Intent i = new Intent(this, Main5Activity.class);
i.putExtra("dato",diezmob.getText().toString());
startActivity(i);
break;
case R.id.btncalcular10:
Intent ii = new Intent(this, Main5Activity.class);
startActivity(ii);
break;
case
R.id.btncalcular15:
Intent iii = new Intent(this, Main5Activity.class);
startActivity(iii);
break;
default:
break;
}
}
}
富國滬深
TA貢獻1790條經驗 獲得超9個贊
讓我們來評估一下：
if ((cinco.toString().equals("")) && (!cinco.toString().equals(null)) && (cinco.toString().isEmpty() || (cinco.toString().length() >= 0))) {
double valor1 = Double.parseDouble((cinco.getText().toString()));
你說如果（“cinco是一個空字符串”）和（不是空）和（是空的（與空字符串相同））或長度>= 0），那么解析雙精度
我很確定唯一一次這個評估為真的是，如果cinco是空的，這將導致一個數字格式異常，因為你試圖解析cinco一個雙倍，而它是空的。您必須使用試捕獲塊處理異常：
try {
double valor1 = Double.parseDouble((cinco.getText().toString()));
} catch (NumberFormatException e) {
e.printStackTrace();
}
或者構造如果不允許在 cinco 為空時對其進行求值的語句：
if(cinco.toString() != null && !(cinco.toString().isEmpty() {
double valor1 = Double.parseDouble((cinco.getText().toString()));
}
編輯：代碼中的所有雙精度雙倍都會拋出數字格式異常，而不僅僅是順便說一句。那個只是第一個，所以這個答案適用于所有解析。
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