java - 无法修改 ListView 中的值

标签 java android android-listview android-arrayadapter android-adapter

我遇到了这个问题

java.lang.UnsupportedOperationException

我想做的很简单，我给你看一个例子。

我的列表

蓝色
红色
绿色

当我在 OnItemLongClickListener() 上创建 Green 时，我的列表应该如下所示:

我的列表

绿色

我尝试过的是

final ArrayAdapter < String > adapter = new ArrayAdapter < String > (getActivity(), android.R.layout.simple_list_item_1, FileBackup.getFilesFound());
adapter.setNotifyOnChange(true);
lv.setAdapter(adapter);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

    @Override
    public boolean onItemLongClick(AdapterView <? > arg0, View arg1, final int arg2, long arg3) {
        String itemValue = (String) lv.getItemAtPosition(arg2);
        Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());
        FileBackup.setNameFile(itemValue);
        final Dialog dialog = new Dialog(getActivity());
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        dialog.setContentView(R.layout.user_file_choose);
        Button button = (Button) dialog.findViewById(R.id.btOk);
        Button button2 = (Button) dialog.findViewById(R.id.btKo);
        TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
        tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                dialog.dismiss();
                //Clear all the ListView
                lv.setAdapter(null);

            }
        });
    }
});

如果我想清除 ListView ，它工作正常，但就我而言，我不想这样做，我尝试添加项目或删除:

adapter.addAll("Something");

或

lv.removeViewAt(2);

然后调用 adapter.notifyDataSetChanged(); 但每次我尝试时都会给出相同的错误。

我做错了什么？

编辑

现在代码如下:

final ArrayAdapter < String > adapter = new ArrayAdapter < String > (getActivity(), Arrays.asList(FileBackup.getFilesFound()));
adapter.setNotifyOnChange(true);
lv.setAdapter(adapter);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

    @Override
    public boolean onItemLongClick(AdapterView <? > arg0, View arg1, final int arg2, long arg3) {
        String itemValue = (String) lv.getItemAtPosition(arg2);
        Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());
        FileBackup.setNameFile(itemValue);
        final Dialog dialog = new Dialog(getActivity());
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        dialog.setContentView(R.layout.user_file_choose);
        Button button = (Button) dialog.findViewById(R.id.btOk);
        Button button2 = (Button) dialog.findViewById(R.id.btKo);
        TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
        tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                dialog.dismiss();
                //Clear all the ListView
                lv.setAdapter(null);
                //Trying to add that current item clicked
                adapter.addAll(FileBackup.getNameFile());
                adapter.notifyDataSetChanged();

            }
        });
    }
});

这是 LogCat 错误:

06-10 20:14:43.531    8072-8072/info.androidhive.tabsswipe E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: info.androidhive.tabsswipe, PID: 8072
java.lang.UnsupportedOperationException
        at java.util.AbstractList.add(AbstractList.java:404)
        at java.util.AbstractList.add(AbstractList.java:425)
        at java.util.Collections.addAll(Collections.java:2583)
        at android.widget.ArrayAdapter.addAll(ArrayAdapter.java:211)
        at info.androidhive.tabsswipe.BackupWA$1$1.onClick(BackupWA.java:80)
        at android.view.View.performClick(View.java:4456)
        at android.view.View$PerformClick.run(View.java:18462)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5102)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

它指向的位置 --> adapter.addAll(FileBackup.getNameFile()); 但它不为 null 我也尝试过 adapter.addAll("RED");

编辑2

我试图保留我在 FileBackup.getFilesFound() 中单击的名称，以便我可以再次创建我的适配器，我正在这样做:

String[] itemvalues = (String[]) lv.getItemAtPosition(arg2);
FileBackup.setFilesFound(itemvalues);

然后我正在做:

 adapter.addAll(Arrays.asList(FileBackup.getFilesFound()));
 //Add the name
 adapter.notifyDataSetChanged();

在我的类上声明为 String[] ，错误是:

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.String[]

编辑3

每次我想更新列表时，它都会给出相同的错误......@Y.S.说最好发布我的所有代码来看看发生了什么，因为我在某个地方使用 String[] 而不是 ArrayList<String>

这是我的 FileBackup.java 

    public class FileBackup {

    private String path;
    private String pathFile;
    private File FileToBackUp;
    private String SDpath;
    private String[] FilesFound;
    private String nameFile;

    public String getPathFile() {
        return pathFile;
    }

    public void setPathFile(String pathFile) {
        this.pathFile = pathFile;
    }
    public String getNameFile() {
        return nameFile;
    }

    public void setNameFile(String nameFile) {
        this.nameFile = nameFile;
    }

    public FileBackup(String path){
        this.path = path;
    }

    public File getFileToBackUp() {
        return FileToBackUp;
    }

    public void setFileToBackUp(File fileToBackUp) {
        FileToBackUp = fileToBackUp;
    }
public String[] getFilesFound() {
       this.FilesFound = FilesFound();

        return FilesFound;
    }
 public String[] FilesFound() {
        File dir = new File(this.path);
        File[] filelist = dir.listFiles();
        String[] theNamesOfFiles = new String[filelist.length];
        for (int i = 0; i < theNamesOfFiles.length; i++) {

            theNamesOfFiles[i] = filelist[i].getName();
        }

        return theNamesOfFiles;
    }

这就是我获得文件列表的方式。

final String itemValue = (String) lv.getItemAtPosition(arg2);

 Log.d("Item clicked --> ", lv.getItemAtPosition(arg2).toString());


 final Dialog dialog = new Dialog(getActivity());
 dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
 dialog.setContentView(R.layout.user_file_choose);
 Button button = (Button) dialog.findViewById(R.id.btOk);
 Button button2 = (Button) dialog.findViewById(R.id.btKo);
 FileBackup.setNameFile(itemValue);
 TextView tvBackUpFile = (TextView) dialog.findViewById(R.id.textViewContentDialog);
 tvBackUpFile.setText("Do you want to backup " + FileBackup.getNameFile() + " ?");
 button.setOnClickListener(new View.OnClickListener() {
     public void onClick(View v) {
         //The complete path of the fail
         FileBackup.setPathFile(GlobalConstant.path + "/" + FileBackup.getNameFile());
         //Converting the path of the file to a File and putting it to FileToBackUp
         FileBackup.setFileToBackUp(PathToFile(FileBackup.getPathFile()));

         dialog.dismiss();
         //Clear all the ListView
         lv.setAdapter(null);

         //Add the name
         BackUpFile.setEnabled(true);


     }
 });

我尝试做类似的事情:

button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        //The complete path of the fail
        FileBackup.setPathFile(GlobalConstant.path + "/" + FileBackup.getNameFile());
        //Converting the path of the file to a File and putting it to FileToBackUp
        FileBackup.setFileToBackUp(PathToFile(FileBackup.getPathFile()));
        ///// THIS IS NEW ///////////
        String itemvalues = (String) lv.getItemAtPosition(arg2);
        FileBackup.setFilesFound(new String[] {
            itemvalues
        });
        adapter.addAll(FileBackup.getFilesFound());
        //Add the name
        adapter.notifyDataSetChanged();
        //////////TIL HERE/////////////
        dialog.dismiss();
        //Clear all the ListView


        //Add the name
        BackUpFile.setEnabled(true);


    }
});

这是 LogCat

 java.lang.UnsupportedOperationException
        at java.util.AbstractList.add(AbstractList.java:404)
        at java.util.AbstractList.add(AbstractList.java:425)
        at java.util.AbstractCollection.addAll(AbstractCollection.java:76)
        at android.widget.ArrayAdapter.addAll(ArrayAdapter.java:195)
        at info.androidhive.tabsswipe.BackupWA$1$1.onClick(BackupWA.java:88)
        at android.view.View.performClick(View.java:4456)
        at android.view.View$PerformClick.run(View.java:18462)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5102)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

指向哪里

adapter.addAll(Arrays.asList(FileBackup.getFilesFound()));

我也尝试过

adapter.addAll(FileBackup.getFilesFound());

但它给出了同样的错误...也许是我在不正确的地方执行此操作...

最佳答案

看看这个答案: ArrayAdapter

基本上正如这个答案所说:“ArrayAdapter 在由数组初始化时，将数组转换为无法修改的 AbstractList(列表)。”

很简单，创建您自己的 ArrayList(在您的 String 类型的情况下)，然后将其分配给 CustomAdapter，然后您可以从 ArrayList 中删除项目，notifyDataSetChanged() 应该可以工作。

问候

关于java - 无法修改 ListView 中的值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30763643/

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