Question

我有一个转换货币的应用程序，当输入一个值为美元金额时它会起作用但是如果用户没有在textview中输入任何值然后按下它会崩溃的按钮我该怎么做呢1.它没有崩溃 2.它通过Toast消息告诉用户没有输入任何值

这是我的代码

package com.example.user.currencyconverter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

public void convert(View view) {

    EditText dollarfield = (EditText) findViewById(R.id.dollarfield);

        Double dollarAmount = Double.parseDouble(dollarfield.getText().toString());

        Double poundAmount = dollarAmount * 0.7;

        Toast.makeText(getApplicationContext(), poundAmount.toString() + "Pounds", Toast.LENGTH_LONG).show();

}




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

Answer 1

    if (dollarfield.getText().toString().equals(""))
    {
            Toast.makeText(getApplicationContext(), "no value has been entered", Toast.LENGTH_LONG).show();

    }
    else
    {
Double dollarAmount = Double.parseDouble(dollarfield.getText().toString());

            Double poundAmount = dollarAmount * 0.7;

            Toast.makeText(getApplicationContext(), poundAmount.toString() + "Pounds", Toast.LENGTH_LONG).show();
    }

如何在按下按钮时阻止我的货币转换器应用程序崩溃？

1 个答案: