java - 从 EditText 读取行并将字符串添加到 ArrayList

Question

您好，这是我想在 Android 中重建的 Java 代码，但我遇到了一些问题。 java代码:

package pickrandom;

import static java.lang.System.in;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
import java.util.Random;

public class Pickrandom {
    static Random randomGenerator;

    static Scanner userInput = new Scanner(System.in);
    static List<String> strings = new ArrayList<String>();

    private static void displayList() {
        System.out.println(strings);
    }

    public static void main(String[] args) {
        // TODO code application logic here

        System.out.println("Please enter your strings:");
        String names;
        String item;
        while (true){
            names = userInput.next();
            if(names.equalsIgnoreCase("quit"))
                break;
            else
                strings.add(names);
        }
        displayList();

        randomGenerator = new Random();

        int index = randomGenerator.nextInt(strings.size());
        item=strings.get(index);

        System.out.println("Picked name is: " + item);
    }

}

这是输出:

Please enter your strings: 
cafe 
bar 
cinema 
quit 
[cafe, bar, cinema] 
Picked name is: cafe

我想在我的Android程序中编写类似的代码。我想在我的编辑文本中逐行写入一些名称，并随机选择一个名称。

这是我的 XML:

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingLeft="3dp"
    android:text="Enter all names in the field below, each on a separate line:"
    android:textColor="#000000"
    android:textSize="21sp"
    android:textStyle="bold"
    android:layout_marginTop="20dp"
    android:layout_marginBottom="20dp"/>
<EditText
    android:id="@+id/itemList"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<Button
    android:id="@+id/picker"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="PICK ONE"
    android:layout_weight="0"/>
<TextView
    android:id="@+id/result"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingLeft="3dp"
    android:text=""
    android:textColor="#000000"
    android:textSize="21sp"
    android:textStyle="bold"
    android:layout_marginTop="20dp"
    android:layout_marginBottom="20dp"/>

我的主要 Activity :

public class MainActivity extends AppCompatActivity {

    static Random randomGenerator;
    static Scanner userInput = new Scanner(System.in);
    static List<String> strings = new ArrayList<String>();

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

        Button btn = (Button) findViewById(R.id.picker);

        final EditText itemList = (EditText) findViewById(R.id.itemList);
        final TextView myTextView = (TextView)findViewById(R.id.result);

        btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {

                String items = itemList.getText().toString();

                String pickedItem;
                while (userInput.hasNextLine()){
                    strings.add(items);
                }
                randomGenerator = new Random();
                int index = randomGenerator.nextInt(strings.size());
                pickedItem=strings.get(index);

                myTextView.setText("Result: \n" + pickedItem);
            }
        });
    }
}

正如我在标题中提到的，我认为我在从 EditText 读取行并将字符串添加到 ArrayList 时遇到问题。预先感谢您的帮助

Answer 1

您不应该再使用扫描仪。

从 EditText 获取字符串后，您应该将其拆分以获取每一行。然后将所有子字符串添加到您的列表中。

btn.setOnClickListener(new View.OnClickListener(){
    @Override
    public void onClick(View v) {

        String items = itemList.getText().toString();
        String[] subStrings = items.split("\n"); //split your String at every new line
        String pickedItem;
        strings.clear();
        for(String s : subStrings){ //run through all substrings to add them to the list
            strings.add(s);
        }
        randomGenerator = new Random();
        int index = randomGenerator.nextInt(strings.size());
        pickedItem=strings.get(index);

        myTextView.setText("Result: \n" + pickedItem);
    }
});