Question

我正在开发一个小型的Android应用程序，让用户猜出1-100之间的数字，它会说猜测是正确的，是太小还是太高。它仍处于开发阶段，这是最基本的代码。我想提到的另一件事是我是初学Android程序员，这是我的第二个应用程序。

activity_main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <EditText android:id="@+id/number_input"
        android:layout_weight="2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:inputType="number" />

    <Button android:id="@+id/guess_button"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/guess_button" />
</LinearLayout>

<TextView android:id="@+id/message_view"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:textSize="20sp" />

</LinearLayout>

MainActivity.java 包com.vessialte.guessthenumber;

import java.util.Random;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    Button guess_button;
    TextView message_view;
    EditText number_input;

    int number;
    int randNumber;
    Random r;

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

        // initialize views
        guess_button = (Button) findViewById(R.id.guess_button);
        message_view = (TextView) findViewById(R.id.message_view);
        number_input = (EditText) findViewById(R.id.number_input);

        number = Integer.parseInt(number_input.getText().toString());

        // button click listener
        guess_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (number < 1 || number > 100) {
                    AlertDialog.Builder errDialog = new AlertDialog.Builder(MainActivity.this)
                    .setTitle("Error")
                    .setMessage("The number has to be between 1 and 100")
                    .setNeutralButton("OK", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            // temporary
                        Toast.makeText(getApplicationContext(), "OK button clicked", Toast.LENGTH_LONG).show();
                        }
                    });

                    errDialog.show();
                } else {
                    r = new Random();
                    randNumber = r.nextInt(100) + 1;

                    if (number == randNumber) {
                        message_view.setText("Your guess was correct! The number is: " + randNumber);
                    } else if (number < randNumber) {
                        message_view.setText("Your guess was too low! The number is: " + randNumber);
                    } else if (number > randNumber) {
                        message_view.setText("Your guess was too high! The number is: " + randNumber);
                    }
                }
            }
        });
}

}

提前非常感谢你。

Answer 1

这必须在onClickListener中。

number = Integer.parseInt(number_input.getText().toString());

你猜我猜NumberFormatException。因为Initially Edittext Value为空，并且您尝试转换为整数。

guess_button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
       number = Integer.parseInt(number_input.getText().toString());
    }
});

Answer 2

您尝试从number_input editText获取值，甚至在填写任何内容之前。移动

number = Integer.parseInt(number_input.getText().toString());

在setOnClickListener()内，这样你只要在点击guess_button时就让android获取值，因此editText中有一个值。

P.S。进行检查以确保在单击guess_button时editText不为空，否则您将再次收到错误。

应用程序在启动时立即崩溃

2 个答案: