Question

我有一个微调器这个问题+我是新的关于android所以idk做什么我已经搜索了几天没有找到任何东西但是PLZ帮助D：

asignatura = (Spinner) findViewById(R.id.spinnerAsignaturas);
    modificar = 0;
    // fin inflates
    Cursor cursor = getContentResolver().query(
            BDProvider.ASIGNATURAS_CONTENT_URI,
            new String[] { BDProvider.ID, BDProvider.ASIGNATURA_NOMBRE },
            null, null, BDProvider.ID);
    SimpleCursorAdapter adaptador = new SimpleCursorAdapter(this,
            android.R.layout.simple_spinner_item, cursor,
            new String[] { BDProvider.ASIGNATURA_NOMBRE },
            new int[] { android.R.id.text1 });

    adaptador
            .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    asignatura.setAdapter(adaptador);
    asignatura.setOnItemSelectedListener(new OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) {
            idAsignatura = (String) ((TextView) arg1).getText();
            setIdAsignatura(idAsignatura);
        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) {}

    });

日志：

  01-06 14:25:54.790: E/AndroidRuntime(5170): java.lang.NullPointerException
01-06 14:25:54.790: E/AndroidRuntime(5170):     at es.uvigo.esei.dm.p06.InsertarTarea$2.onItemSelected(InsertarTarea.java:85)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.AdapterView.fireOnSelected(AdapterView.java:893)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.AdapterView.selectionChanged(AdapterView.java:880)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.AdapterView.checkSelectionChanged(AdapterView.java:1043)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.AdapterView.handleDataChanged(AdapterView.java:1023)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:180)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.Spinner.onMeasure(Spinner.java:482)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.View.measure(View.java:16458)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1052)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.View.measure(View.java:16458)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.forceUniformWidth(LinearLayout.java:940)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:920)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.View.measure(View.java:16458)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.View.measure(View.java:16458)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
01-06 14:25:54.790: E/AndroidRuntime(5170):     at android.view.View.measure(View.java:16458)

它说onItemSelected上的视图为null但我不知道为什么，我认为光标是在设置适配器之前获取数据....

Answer 1

我假设您的TextView为空，getText（）返回null。而不是直接转换为String，尝试类似：

CharSequence cidAsignatura = ((TextView) arg1).getText();
if (cidAsignatura != null) {
  setIdAsignatura(cidAsignatura.toString());
}

Answer 2

好的，我发现一个简单的但不确定这是一个有效的方法，使它工作，但如果你

@Override
    public void onItemSelected(AdapterView<?> arg0, View arg1,
            int arg2, long arg3) {
        idAsignatura = (String) ((TextView) arg1).getText();
        setIdAsignatura(idAsignatura);
    }

采取＆＃34; arg1＆＃34;你这样做：

@Override
        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) {

            if(arg1!=null){
                setIdAsignatura((String) ((TextView) arg1).getText());
            }
        }

它不会崩溃！谢谢Rares Barbatan。

旋转屏幕时，Android微调器会崩溃

2 个答案: