列表视图一遍又一遍地只显示最后一项
Listview show only last item over and over
我是 android 开发的新手。我注册了 Udacity 课程,我到达了必须使用服装 arrayAdapter 来显示数据列表视图(文本)的地方,我确定了其中的大部分内容,但我在显示数据时遇到了问题,即:当我启动我的 activity listView 显示 arraylist 上的最后一项
我已经尝试了几乎所有方法,但对我没有用
我的数据
/**
* Displays text to the user.
*/
public class Numbers {
//First we Set the Stat of our Class :
// English Translation
public static String englishTranslation;
//Tamazight Translation
public static String tamazightTranslation;
/**
* Create a new Numbers Object :
*
* @param englishTranslation is for ENGLISH NUMBERS
* @param tamazightTranslation is for TAMAZIGHT NUMBERS
*/
//Constructor
public Numbers(String englishTranslation, String tamazightTranslation) {
this.englishTranslation = englishTranslation;
this.tamazightTranslation = tamazightTranslation;
}
//Getter
public static String getEnglishTranslation() {
return englishTranslation;
}
public static String getTamazightTranslation() {
return tamazightTranslation;
}
}
我的数组列表:
public class ActivityNumbers extends AppCompatActivity {
//Add English numbers to The ARRAYList
ArrayList<Numbers> englishNumbers = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_numbers);
englishNumbers.add(new Numbers("One", "Yan"));
englishNumbers.add(new Numbers("Two", "Sin"));
englishNumbers.add(new Numbers("Three", "Krad"));
englishNumbers.add(new Numbers("Four", "Koz"));
englishNumbers.add(new Numbers("Five", "Smos"));
englishNumbers.add(new Numbers("Six", "Sdis"));
englishNumbers.add(new Numbers("Seven", "Sa"));
englishNumbers.add(new Numbers("Eight", "Tam"));
englishNumbers.add(new Numbers("Nine", "Tza"));
englishNumbers.add(new Numbers("Ten", "Mraw"));
//EnglishNumbers.remove(0);
//EnglishNumbers.size();
// EnglishNumbers.get(1);
//Create a NEW TV object
/**Creating an ArrayAdapter (DATA HOLDER)
@param Context / the ACTIVITY concerned
@param Android.R.layout : an XML layout file contains TextView predefined by Android
@param Items to display */
NumbersAdapter itemsAdapter = new NumbersAdapter (this, englishNumbers);
// Linking the ListView object to a Variable
ListView numbersListView = (ListView) findViewById(R.id.list);
//Calling setAdapter Method on numbersListView with "itemsAdapter
numbersListView.setAdapter(itemsAdapter);
}
}
我的适配器:
public class NumbersAdapter extends ArrayAdapter<Numbers> {
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
super(context, 0, englishNumbers);
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
View listItemView = convertView;
if (listItemView == null) {
listItemView = LayoutInflater.from(getContext()).inflate(R.layout.listitem, parent, false);
}
Numbers numbers = getItem(position);
System.out.println(position);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(numbers.getEnglishTranslation());
System.out.println(numbers.getEnglishTranslation());
english_item.setText(numbers.getTamazightTranslation());
System.out.println(numbers.getTamazightTranslation());
return listItemView;
}
}
您的 tamazightTranslation
和 englishTranslation
属性在 Numbers
class 上是静态的,这意味着它们是 class 属性。从变量和吸气剂中删除 static
,你应该没问题。在此处查看 class 属性和实例属性之间的区别 https://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html
试试这个方法
Context context;
ArrayList<Numbers> englishNumbers;
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers)
{
this.context=context;
this.englishNumbers=englishNumbers;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
convertView= LayoutInflater.from(context).inflate(R.layout.listitem,parent,false);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(englishNumbers.get(position).getEnglishTranslation());
english_item.setText(englishNumbers.get(position).getTamazightTranslation());
return convertView;
}
并且不要忘记让 NumbersAdapter 扩展 BaseAdapter
我已经更改了您的型号 class 和适配器 class 请按照此操作 它会起作用
public class Numbers {
//First we Set the Stat of our Class :
// English Translation
private String englishTranslation;
//Tamazight Translation
private String tamazightTranslation;
public String getEnglishTranslation() {
return englishTranslation;
}
public void setEnglishTranslation(String englishTranslation) {
this.englishTranslation = englishTranslation;
}
public String getTamazightTranslation() {
return tamazightTranslation;
}
public void setTamazightTranslation(String tamazightTranslation) {
this.tamazightTranslation = tamazightTranslation;
}
}
适配器 Class
public class NumbersAdapter extends ArrayAdapter<Numbers> {
private Context mContext;
private ArrayList<Numbers>list;
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
super(context, 0, englishNumbers);
this.mContext=context;
this.list = englishNumbers;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
View listItemView = convertView;
if (listItemView == null) {
listItemView = LayoutInflater.from(mContext).inflate(R.layout.listitem, parent, false);
}
Numbers numbers = list.get(position);
System.out.println(position);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(numbers.getEnglishTranslation());
System.out.println(numbers.getEnglishTranslation());
english_item.setText(numbers.getTamazightTranslation());
System.out.println(numbers.getTamazightTranslation());
return listItemView;
}
}
如果它在您的列表视图中显示最后一项,可能有多种原因。
您需要覆盖 ArrayAdapter 中的 getCount()
以获得列表的大小。它可能会解决问题。
确保列表视图未在 xml 布局中的滚动视图内声明。如果是,请使用 nestedscrollview 或其他方式正确处理它。
如果它在列表视图的所有行中显示相同的数据,那么它可能是
- 在你的情况下,你需要去掉属性前面的
static
关键字,static
表示属性或方法属于Number class,而不是你Number的实例class 对象。基本上肯定是这个原因。
我是 android 开发的新手。我注册了 Udacity 课程,我到达了必须使用服装 arrayAdapter 来显示数据列表视图(文本)的地方,我确定了其中的大部分内容,但我在显示数据时遇到了问题,即:当我启动我的 activity listView 显示 arraylist 上的最后一项 我已经尝试了几乎所有方法,但对我没有用
我的数据
/**
* Displays text to the user.
*/
public class Numbers {
//First we Set the Stat of our Class :
// English Translation
public static String englishTranslation;
//Tamazight Translation
public static String tamazightTranslation;
/**
* Create a new Numbers Object :
*
* @param englishTranslation is for ENGLISH NUMBERS
* @param tamazightTranslation is for TAMAZIGHT NUMBERS
*/
//Constructor
public Numbers(String englishTranslation, String tamazightTranslation) {
this.englishTranslation = englishTranslation;
this.tamazightTranslation = tamazightTranslation;
}
//Getter
public static String getEnglishTranslation() {
return englishTranslation;
}
public static String getTamazightTranslation() {
return tamazightTranslation;
}
}
我的数组列表:
public class ActivityNumbers extends AppCompatActivity {
//Add English numbers to The ARRAYList
ArrayList<Numbers> englishNumbers = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_numbers);
englishNumbers.add(new Numbers("One", "Yan"));
englishNumbers.add(new Numbers("Two", "Sin"));
englishNumbers.add(new Numbers("Three", "Krad"));
englishNumbers.add(new Numbers("Four", "Koz"));
englishNumbers.add(new Numbers("Five", "Smos"));
englishNumbers.add(new Numbers("Six", "Sdis"));
englishNumbers.add(new Numbers("Seven", "Sa"));
englishNumbers.add(new Numbers("Eight", "Tam"));
englishNumbers.add(new Numbers("Nine", "Tza"));
englishNumbers.add(new Numbers("Ten", "Mraw"));
//EnglishNumbers.remove(0);
//EnglishNumbers.size();
// EnglishNumbers.get(1);
//Create a NEW TV object
/**Creating an ArrayAdapter (DATA HOLDER)
@param Context / the ACTIVITY concerned
@param Android.R.layout : an XML layout file contains TextView predefined by Android
@param Items to display */
NumbersAdapter itemsAdapter = new NumbersAdapter (this, englishNumbers);
// Linking the ListView object to a Variable
ListView numbersListView = (ListView) findViewById(R.id.list);
//Calling setAdapter Method on numbersListView with "itemsAdapter
numbersListView.setAdapter(itemsAdapter);
}
}
我的适配器:
public class NumbersAdapter extends ArrayAdapter<Numbers> {
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
super(context, 0, englishNumbers);
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
View listItemView = convertView;
if (listItemView == null) {
listItemView = LayoutInflater.from(getContext()).inflate(R.layout.listitem, parent, false);
}
Numbers numbers = getItem(position);
System.out.println(position);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(numbers.getEnglishTranslation());
System.out.println(numbers.getEnglishTranslation());
english_item.setText(numbers.getTamazightTranslation());
System.out.println(numbers.getTamazightTranslation());
return listItemView;
}
}
您的 tamazightTranslation
和 englishTranslation
属性在 Numbers
class 上是静态的,这意味着它们是 class 属性。从变量和吸气剂中删除 static
,你应该没问题。在此处查看 class 属性和实例属性之间的区别 https://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html
试试这个方法
Context context;
ArrayList<Numbers> englishNumbers;
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers)
{
this.context=context;
this.englishNumbers=englishNumbers;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
convertView= LayoutInflater.from(context).inflate(R.layout.listitem,parent,false);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(englishNumbers.get(position).getEnglishTranslation());
english_item.setText(englishNumbers.get(position).getTamazightTranslation());
return convertView;
}
并且不要忘记让 NumbersAdapter 扩展 BaseAdapter
我已经更改了您的型号 class 和适配器 class 请按照此操作 它会起作用
public class Numbers {
//First we Set the Stat of our Class :
// English Translation
private String englishTranslation;
//Tamazight Translation
private String tamazightTranslation;
public String getEnglishTranslation() {
return englishTranslation;
}
public void setEnglishTranslation(String englishTranslation) {
this.englishTranslation = englishTranslation;
}
public String getTamazightTranslation() {
return tamazightTranslation;
}
public void setTamazightTranslation(String tamazightTranslation) {
this.tamazightTranslation = tamazightTranslation;
}
}
适配器 Class
public class NumbersAdapter extends ArrayAdapter<Numbers> {
private Context mContext;
private ArrayList<Numbers>list;
public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
super(context, 0, englishNumbers);
this.mContext=context;
this.list = englishNumbers;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
View listItemView = convertView;
if (listItemView == null) {
listItemView = LayoutInflater.from(mContext).inflate(R.layout.listitem, parent, false);
}
Numbers numbers = list.get(position);
System.out.println(position);
TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);
tamazight_item.setText(numbers.getEnglishTranslation());
System.out.println(numbers.getEnglishTranslation());
english_item.setText(numbers.getTamazightTranslation());
System.out.println(numbers.getTamazightTranslation());
return listItemView;
}
}
如果它在您的列表视图中显示最后一项,可能有多种原因。
您需要覆盖 ArrayAdapter 中的
getCount()
以获得列表的大小。它可能会解决问题。确保列表视图未在 xml 布局中的滚动视图内声明。如果是,请使用 nestedscrollview 或其他方式正确处理它。
如果它在列表视图的所有行中显示相同的数据,那么它可能是
- 在你的情况下,你需要去掉属性前面的
static
关键字,static
表示属性或方法属于Number class,而不是你Number的实例class 对象。基本上肯定是这个原因。