java - 单击按钮时如何在 TextView 中显示 ArrayList？

Question

我是 Android 编程新手，过去 3 个月一直在观看 YouTube 视频，试图通过反复试验来学习。我被困住了。

我想做的就是在单击屏幕上的按钮后在 TextView (robotJoke) 中显示我的“JokeList.java”。有人可以帮我吗？

这是我的 MainActivity.java 文件

package com.example.wdoty.comedianrobot;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import java.lang.String;
import java.util.ArrayList;

public class MainActivity extends Activity{

ArrayList<String> jokeList;
TextView robotJoke;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    robotJoke = (TextView) findViewById(R.id.robotJoke);

}

public void buttonClicked(){
    printJoke();
}

public void printJoke(){
    String jokeString = jokeList.toString();
    robotJoke.setText(jokeString);
}


}

这是我的 ArrayList.java (JokeList.java)

package com.example.wdoty.comedianrobot;
import java.util.*;



public class JokeList extends MainActivity{

public void jokes(){

    ArrayList<String> jokeList = new ArrayList<String>();

    jokeList.add("Why couldn't the bicycle stand up?"+
            "Because it was two tired");
    jokeList.add("What do you call a cheese that isn't yours?"+
            "Nacho Cheese!");
    jokeList.add("Before I criticize a man, I like to walk a mile in his shoes."+
            "That way, when I do criticize him, I'm a mile away and I have his shoes.");
    jokeList.add("What do you call a fish with no eye?"+
            "Fssshh");
    jokeList.add("Have you heard the one about the Corduroy pillow?"+
            "It's making HEADLINES!");
    jokeList.add("What's red and bad for your teeth?"+
            "A brick.");
    jokeList.add("Why didn't the melons get married?"+
            "Because they cantaloupe!");
    jokeList.add("What did the cobbler say when a cat wandered into his shop?"+
            "Shoe!");
    jokeList.add("What did the Buddhist say to the hot dog vendor?"+
            "Make me one with everything!");
    jokeList.add("The face of a child can say it all"+
            "especially the mouth part of the face.");
    jokeList.add("Why did the cookie go to the hospital?"+
            "Because he felt crummy.");
    jokeList.add("I intend to live forever..."+
            "So far, so good.");

}

}

这是我的activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity">

<ImageView
    android:layout_width="120dp"
    android:layout_height="120dp"
    android:id="@+id/imageView"
    android:src="@drawable/android"
    android:layout_centerHorizontal="true"/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/robotText"
    android:text="Hello. My name is Andy the Android I like telling jokes. Click the button below if you would like for me to tell you 1."
    android:layout_below="@+id/imageView"
    android:paddingTop="10dp" />
<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/button"
    android:layout_below="@id/robotText"
    android:paddingTop="15dp"
    android:text="Button"
    android:layout_centerHorizontal="true"
    android:onClick="buttonClicked" />
<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/robotJoke"
    android:layout_below="@id/button"
    android:paddingTop="30dp"/>

</RelativeLayout>

Answer 1

您应该循环遍历列表并将列表中的元素一一追加。

public void printJoke(){
    StringBuilder jokeStringBuilder = new StringBuilder();
    for (String s : jokeList) {
        jokeStringBuilder.append(s + "\n");
    }
    robotJoke.setText(jokeStringBuilder.toString());
}

另一个错误是您需要将 buttonClicked() 函数中的 View 传递为 buttonClicked(View v)