Question

这里BookList.java是一个微调器类，它维护两个出现，一个是书，另一个是作者，都有自己的列表视图类。通过在OnItemSelected（）方法内切换案例，可以访问它们的意图。但我面临的问题是，无法访问第一个列表视图应用的意图，但是可以访问作者意图。如果有人帮我编辑我的代码会很有帮助。这是java文件。

            public class BookList extends Activity implements OnItemSelectedListener {

                Spinner spinner;
                //private static final String[]paths = {"Book", "Author"};
                @Override
                protected void onCreate(Bundle savedInstanceState) {
                    super.onCreate(savedInstanceState);
                    setContentView(R.layout.activity_booklist);
                    TextView t =(TextView)findViewById(R.id.t1) ;
                    spinner = (Spinner)findViewById(R.id.spinner);
                    //ArrayAdapter<String>adapter = new ArrayAdapter<String>(BookList.this,
                            //android.R.layout.simple_spinner_item,paths);
                    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.blist_array, android.R.layout.simple_spinner_item);
                    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    spinner.setAdapter(adapter);
                    adapter.notifyDataSetChanged();
                    spinner.setOnItemSelectedListener(this);

                }

                public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {

                    final Intent intent;
                    switch (position) {
                        case 1:
                            intent = new Intent(BookList.this, BookListView.class);
                            startActivity(intent);
                            break;
                        case 2:
                            intent = new Intent(BookList.this, BookListAuthorView.class);
                            startActivity(intent);
                            break;
                    }



                }
                public void onNothingSelected(AdapterView<?> arg0) {
                    Toast.makeText(this, "Please choose a field", Toast.LENGTH_SHORT).show();

                }

}

Answer 1

项目位置从0开始，而不是从1开始，因此请使用此

所以0位置会在你第一次打开你的活动时自动触发，所以为spinner创建一个这样的微调器数组

String arr ={"select choice","book","author"};

                switch (position) {
                    case 1:
                        intent = new Intent(BookList.this, BookListView.class);
                        startActivity(intent);
                        break;
                    case 2:
                        intent = new Intent(BookList.this, BookListAuthorView.class);
                        startActivity(intent);
                        break;
                }

加上你不必调用`adapter.notifyDataSetChanged（）;'

在微调器类

1 个答案: