Question

我试图从Udacity的Android多屏幕应用课程中学习Android ArrayAdapter。我已经完成了课程中提到的所有内容，但无法查看列表视图。此外，没有从Android工作室得到任何错误。

以下是我的代码 -

NumbersActivity.java

package com.example.android.miwok;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;

public class NumbersActivity extends AppCompatActivity {

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

        // Create a list of words
        ArrayList<Word> words = new ArrayList<Word>();

        words.add(new Word("one","lutti"));
        words.add(new Word("two","otikko"));
        words.add(new Word("three","tolokooosu"));
        words.add(new Word("four","oyyisa"));
        words.add(new Word("five","massokka"));
        words.add(new Word("six","temmokka"));
        words.add(new Word("seven","kenakaku"));
        words.add(new Word("eight","kawinta"));
        words.add(new Word("nine","woe"));
        words.add(new Word("ten","naaaache"));


        WordAdapter adapter = new WordAdapter(this, words);

        ListView listView = (ListView) findViewById(R.id.list);

        listView.setAdapter(adapter);

    }
}

WordAdapter.java

package com.example.android.miwok;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * Created by opsol on 15/7/16.
 */
public class WordAdapter extends ArrayAdapter<Word> {

    public WordAdapter(Activity context, ArrayList<Word> words) {
        // Here, we initialize the ArrayAdapter's internal storage for the context and the list.
        // the second argument is used when the ArrayAdapter is populating a single TextView.
        // Because this is a custom adapter for two TextViews and an ImageView, the adapter is not
        // going to use this second argument, so it can be any value. Here, we used 0.
        super(context, 0, words);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // Check if the existing view is being reused, otherwise inflate the view
        View listItemView = convertView;
        if(listItemView == null) {
            listItemView = LayoutInflater.from(getContext()).inflate(
                    R.layout.list_item, parent, false);
        }

        // Get the {@link AndroidFlavor} object located at this position in the list
        Word currentWord = getItem(position);

        // Find the TextView in the list_item.xml layout with the ID version_name
        TextView miwokTextView = (TextView) listItemView.findViewById(R.id.miwok_text_view);
        // Get the version name from the current AndroidFlavor object and
        // set this text on the name TextView
        miwokTextView.setText(currentWord.getmMiwokTranslation());

        // Find the TextView in the list_item.xml layout with the ID version_number
        TextView defaultTextView = (TextView) listItemView.findViewById(R.id.default_text_view);
        // Get the version number from the current AndroidFlavor object and
        // set this text on the number TextView
        defaultTextView.setText(currentWord.getDefaultTranslation());

        return listItemView;
    }
}

Word.java

package com.example.android.miwok;

/**
 * Created by opsol on 15/7/16.
 */
public class Word {
    private String mDefaultTranslation;
    private String mMiwokTranslation;

    public Word(String mDefaultTranslation, String mMiwokTranslation){
        mDefaultTranslation = mDefaultTranslation;
        mMiwokTranslation = mMiwokTranslation;
    }

    public String getDefaultTranslation(){
        return mDefaultTranslation;
    }

    public String getmMiwokTranslation(){
        return mMiwokTranslation;
    }
}

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    <TextView
        android:id="@+id/miwok_text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="lutti" />

    <TextView
        android:id="@+id/default_text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="one" />

</LinearLayout>

activity_numbers.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/list"
    android:orientation="vertical"
    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="com.example.android.miwok.NumbersActivity">

</ListView>

我的列表视图的屏幕截图 -

有人帮我理解这里的错误吗？

此致

Answer 1

您的Word类构造函数应该如下所示

public Word(String mDefaultTranslation, String mMiwokTranslation) {
        this.mDefaultTranslation = mDefaultTranslation;
        this.mMiwokTranslation = mMiwokTranslation;
    }

列出Android ArrayAdapter示例中不可见的内容

1 个答案: