spinner.setSelection 幫助

Question

我正在嘗試加載我的首選項並更新微調器以顯示先前保存的值。 我以前從未使用過 spinner.setSelection 並不斷收到 nullpointerexceptions。

String[] timeItems = new String[] {"After 2 minutes", "After 5 minutes", "Never"};
ArrayAdapter<String> adapter;
Spinner screenSpinner;

創建（）：

Spinner screenSpinner = (Spinner)findViewById(R.id.spinner_screen);
        screenSpinner.setOnItemSelectedListener(new MyOnItemSelectedListener());
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, timeItems);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        screenSpinner.setAdapter(adapter);

加載首選項（）

    //load the preferences
...
    //then update the selection in the spinner    
    if (mScreenTimer == SCREEN_TIMER_2MINUTES) {
                    int tmp_index = adapter.getPosition("After 2 minutes");
                    screenSpinner.setSelection(tmp_index,true);
                } else if (mScreenTimer == SCREEN_TIMER_5MINUTES) {
                    int tmp_index = adapter.getPosition("After 5 minutes");
                    screenSpinner.setSelection(tmp_index,true);
                } else if (mScreenTimer == SCREEN_TIMER_NEVER) {
                    int tmp_index = adapter.getPosition("Never");
                    screenSpinner.setSelection(tmp_index,true);
                }

我在 screenSpinner.setSelection(tmp_index, true) 上得到 NullPointerExecption

Answer 1

設置適配器后嘗試設置選擇