Question

以下MainActivity.java仅包含几个if/else块：

// Simple array with a list of languages
    String[] languages = {"Arabic", "Armenian", "Cantonese", "Cherokee",
            "Czech", "Dutch", "English", "French", "Gaelic", "German",
            "Greek", "Haitian Creole", "Hawaiian", "Italian", "Japanese", "Korean",
            "Mandarin", "Navajo", "Philippines Tagalog", "Polish", "Portuguese", "Romanian",
            "Russian", "Spanish", "Swedish", "Vietnamese"};

    // Simple array with a list of the spelling for Merry Christmas in language 
    final String[] merrychristmas = {"Eid Melad Majeed", "Shnorhavor Surb Tsnund",
            "Sing-daan Faai-lohk", "ulihelisdi hunadetiyisgvi", "veselé vánoce",
            "vrolijk kerstfeest", "Merry Christmas!", "joyeux Noël", "Nollaig Shona Duit",
            "frohe Weihnacten", "Kalá Christoúgenna", "Jwaye Nwèl", "Mele Kalikimaka",
            "Buon Natale", "Merīkurisumasu", "jilgohun-christmas-bonoseyo",
            "Shèndàn kuàilè", "Nizhónígo Késhmish Da'doohleel", 
            "Mąligayang Pasko", "Wesołych Świąt", "Feliz Natal", "Crăcuin fericit",
            "schastlivogo Rozhdestva", "Feliz Navidad", "god jul", "Chúc Mừng Giáng Sinh"};

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

    rowItems = new ArrayList<DataModel>();
    for (int i = 0; i < languages.length; i++) {
        DataModel item = new DataModel(languages[i]);
        rowItems.add(item);
    }

    listView = (ListView) findViewById(R.id.listView1);
    CustomAdapter adapter = new CustomAdapter(this, R.layout.item_row, rowItems);
    listView.setAdapter(adapter);
    listView.setOnItemClickListener(this);

}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
LinearLayout layout = new LinearLayout(MainActivity.this);
    layout.setBackgroundResource(R.drawable.circle);
    TextView tv = new TextView(MainActivity.this);
    // set the TextView properties
    tv.setTextColor(Color.WHITE);
    tv.setTextSize(20);
    tv.setPaddingRelative(22, 108, 0, 0);
    tv.setGravity(Gravity.FILL);
    tv.setText(merrychristmas[position]);
    layout.addView(tv);
    Toast toast = new Toast(MainActivity.this);

    if (position == 0) {
        Toast.makeText(getApplicationContext(),
                merrychristmas[position], Toast.LENGTH_LONG);
        toast.setView(layout);
        toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
        toast.show();
        _player = MediaPlayer.create(MainActivity.this, R.raw.arabic);
        _player.start();
    }
    if (position == 1) {
        Toast.makeText(getApplicationContext(),
                merrychristmas[position], Toast.LENGTH_LONG);
        // set the layout as the toast view
        toast.setView(layout);
        toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
        toast.show();
        _player = MediaPlayer.create(MainActivity.this, R.raw.armenian);
        _player.start();
    }
    if (position == 2) {
        Toast.makeText(getApplicationContext(),
                merrychristmas[position], Toast.LENGTH_LONG);

CustomAdapter.java：

public class CustomAdapter extends ArrayAdapter<DataModel> {

    Context context;

    /****** custom adapter constructor ******/
    public CustomAdapter(Context context, int resourceId, List<DataModel> data) {
        super(context, resourceId, data);
        this.context = context;
    }

    /****** create a holder class to contain inflated xml file elements ******/

    private class ViewHolder {
        public TextView txtlanguage;
    } 

    /**
    **** create each ListView row *****
    */
    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder holder = null;
        DataModel rowItem = getItem(position);

        LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

        if (convertView == null) {
            /****** Inflate item_row file for each row ******/
            convertView = mInflater.inflate(R.layout.item_row, null);
            /****** ViewHolder object to contain item_row.xml file elements ******/
            holder = new ViewHolder();
            holder.txtlanguage = (TextView) convertView.findViewById(R.id.text1);
            /****** set holder with LayoutInflater ******/
            convertView.setTag(holder);
        } else
            holder = (ViewHolder) convertView.getTag();

        /****** set model values in Holder elements ******/
        holder.txtlanguage.setText(rowItem.getLanguage());
        /****** set itemClickListener for LayoutInflater for each row ******/
        return convertView;
    }
}

对于DataModel.java：

public class DataModel {

private String language;

public DataModel(String language) {
    this.language = language;
}

/****** get methods ******/
public String getLanguage() {
    return this.language;
}
/****** set methods ******/
public void setLanguage(String language) {
    this.language = language;
}

} // end class DataModel

这里是崩溃转储：

10-12 08:53:01.135    1134-1134/com.blogspot.joyouslybeingjoy.merrychristmas
W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb3a86ba8)
10-12 08:53:01.155    1134-1134/com.blogspot.joyouslybeingjoy.merrychristmas 
E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.blogspot.joyouslybeingjoy.merrychristmas, PID: 1134
java.lang.ClassCastException: com.blogspot.joyouslybeingjoy.merrychristmas.
DataModel cannot be cast to java.lang.String
        at com.blogspot.joyouslybeingjoy.merrychristmas.MainActivity.
        onItemClick(MainActivity.java:102)
        at android.widget.AdapterView.performItemClick(AdapterView.java:299)
        at android.widget.AbsListView.performItemClick(AbsListView.java:1113)
        at android.widget.AbsListView$PerformClick.run(AbsListView.java:2904)
        at android.widget.AbsListView$3.run(AbsListView.java:3638)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5017)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
        at dalvik.system.NativeStart.main(Native Method)

提前致谢！我确实学到了很多，并且乐在其中！感谢支持！

Answer 1

是CustomAdapter extends ArrayAdapter。使用CustomAdapter extends ArrayAdapter<DataModel> 这是我想的问题，请发布你的102行。

Answer 2

CustomAdapter extends ArrayAdapter

装置

CustomAdapter extends ArrayAdapter <Object>

这样做，它会起作用

CustomAdapter extends ArrayAdapter <DataModel>

Answer 3

错误发生在第102行。我移动了那个和其他一些注释掉的行在同一区域中（实际上是文件的底部）并且我确保CustomAdapter扩展了ArrayAdapter到位，做了一个干净的它正在工作！我现在将所有注释掉的行移到NotePad ++上！非常感谢。真的很喜欢从这个板上学习。

DataModel无法强制转换为java.lang.String

3 个答案: