android - 获取 Android 中微调器的位置

Question

我试图获取微调器的位置（编号），以便在另一个活动中使用它，每次都会根据所选项目显示不同的地图。当我运行应用程序时它崩溃了。这是第一个活动代码：

public class TestProjectActivity extends Activity {
    public Spinner spinner1;
    public Integer number;
    private Button valideButton;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        MySpinner();
        valide_button();

    }

    public void MySpinner() {

        final Spinner spinner1 = (Spinner) findViewById(R.id.spinner1);

        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                this, R.array.num, android.R.layout.simple_spinner_item);
                                      adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner1.setAdapter(adapter);

        spinner1.setOnItemSelectedListener(new OnItemSelectedListener() {

            public void onItemSelected(AdapterView<?> parentView,
                    View selectedItemView, int position, long id) {
                // Object item = parentView.getItemAtPosition(position);

                TestProjectActivity.this.number = spinner1
                        .getSelectedItemPosition() + 1;

            }

            public void onNothingSelected(AdapterView<?> arg0) {// do nothing
            }

        });

    }

    public void valide_button() {

        valideButton = (Button) findViewById(R.id.valide_button);
        valideButton.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                Intent intent = new Intent(TestProjectActivity.this,
                        MetroMapActivity.class);
                startActivity(intent);
            }

        });

    }

}

score 106 · Accepted Answer

选择微调器的方法是：

  spinner1.getSelectedItemPosition();

文档参考： http: //developer.android.com/reference/android/widget/AdapterView.html#getSelectedItemPosition()

但是，在您的代码中，您引用它的一个地方是在您的setOnItemSelectedListener(). 无需轮询微调器，因为该onItemSelected方法将位置作为“位置”变量传递。

因此，您可以将该行更改为：

TestProjectActivity.this.number = position + 1;

如果这不能解决问题，请发布您的应用崩溃时生成的错误消息。

score 2 · Accepted Answer

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt = findViewById(R.id.button);
        spinner = findViewById(R.id.sp_item);
        setInfo();
        spinnerAdapter = new SpinnerAdapter(this, arrayList);
        spinner.setAdapter(spinnerAdapter);



        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                //first,  we have to retrieve the item position as a string
                // then, we can change string value into integer
                String item_position = String.valueOf(position);

                int positonInt = Integer.valueOf(item_position);

                Toast.makeText(MainActivity.this, "value is "+ positonInt, Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });







note: the position of items is counted from 0.

score 1 · Accepted Answer

    final int[] positions=new int[2]; 
    Spinner sp=findViewByID(R.id.spinner);

    sp.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) {
            // TODO Auto-generated method stub
            Toast.makeText( arg2....);
        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }
    });

score 1 · Accepted Answer

if (position ==0) {
    if (rYes.isChecked()) {
        Toast.makeText(SportActivity.this, "yes ur answer is right", Toast.LENGTH_LONG).show();
    } else if (rNo.isChecked()) {
        Toast.makeText(SportActivity.this, "no.ur answer is wrong", Toast.LENGTH_LONG).show();
    }
}

此代码应该选中两个复选框。
有问题吗？

android - 获取 Android 中微调器的位置

4 回答 4

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