在打开的DatePickerDialog中，当屏幕方向更改时，它会重置所选的用户数据。
（DatePickerDialog不关闭，它不维护所选数据）
码：
public class ActivityNeki extends FragmentActivity {
DialogFragment newDF = null;
private int datY, datM, datD;
@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
if(savedInstanceState == null){ setTheData(); writeTheData(); }
}
@Override protected void onSaveInstanceState(Bundle outState) {
outState.putInt("izY", datY); outState.putInt("izM", datM); outState.putInt("izD", datD);
super.onSaveInstanceState(outState);
}
@Override protected void onRestoreInstanceState(Bundle savedInstanceState) { super.onRestoreInstanceState(savedInstanceState);
datY = savedInstanceState.getInt("izY"); datM = savedInstanceState.getInt("izM"); datD = savedInstanceState.getInt("izD");
writeTheData();
}
public void onClickOpenDPD(View view) { // the method that is caled from XML onClick
class MyDialogFragment extends DialogFragment {
@Override public void onDestroyView() {
if (getDialog() != null && getRetainInstance()) getDialog().setDismissMessage(null);
super.onDestroyView();
}
@Override public void onCreate(Bundle state) { super.onCreate(state);
setRetainInstance(true);
}
@Override public Dialog onCreateDialog(Bundle state) {
DatePickerDialog dpd = new DatePickerDialog( getActivity(), new DatePickerDialog.OnDateSetListener() {
@Override public void onDateSet(DatePicker view, int leto, int mesec, int dan) {
datY = leto; datM = mesec; datD = dan;
writeTheData();
} }, datY, datM, datD);
return dpd;
}
}
newDF = new MyDialogFragment();
newDF.show( getSupportFragmentManager(), null );
}
public void setTheData(){
Calendar c = Calendar.getInstance();
datY = c.get(Calendar.YEAR); datM = c.get(Calendar.MONTH); datD = c.get(Calendar.DAY_OF_MONTH);
}
public void writeTheData(){ /* writes the data in a txtView */ }
}
建议我，如何解决这个问题？
正确实现的DialogFragment将能够在没有任何额外工作的情况下恢复状态。代码中的主要问题是非静态内部类。这有缺陷有两个原因：
WeakReferences。
https://stackoverflow.com/a/10968689/1493269故事的道德：小心非静态的内部阶级。
你的代码应该如何工作：
activity nek i.Java
public class ActivityNeki extends FragmentActivity implements DatePickerDialog.OnDateSetListener
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
Fragment fragment = getSupportFragmentManager().findFragmentByTag( "my_dialog_tag" );
if( fragment != null )
{
( (MyDialogFragment) fragment ).listener = this;
}
}
// Called from xml
public void onClickOpenDPD(View view)
{
MyDialogFragment.newInstance( x, x, x, this ).show( getSupportFragmentManager(), "my_dialog_tag" );
}
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth)
{
// Do your crazy callback stuff
}
}
my dialog fragment.Java
class MyDialogFragment extends DialogFragment
{
public static MyDialogFragment newInstance( int datY, int datM, int datD, DatePickerDialog.OnDateSetListener listener )
{
Bundle bundle = new Bundle( 3 );
bundle.putInt( "y", datY );
bundle.putInt( "m", datM );
bundle.putInt( "d", datD );
MyDialogFragment fragment = new MyDialogFragment();
fragment.setArguments( bundle );
fragment.listener = listener;
return fragment;
}
public DatePickerDialog.OnDateSetListener listener = null;
// Not entirely sure if this is still necessary
@Override
public void onDestroyView()
{
if(getDialog() != null && getRetainInstance())
{
getDialog().setDismissMessage(null);
super.onDestroyView();
}
}
@Override
public Dialog onCreateDialog(Bundle state)
{
return new DatePickerDialog(
getActivity(),
listener,
getArguments().getInt( "y" ),
getArguments().getInt( "m" ),
getArguments().getInt( "d" )
);
}
}
请原谅小错误，因为我在没有测试的情况下将其写下来。
你的代码看起来很糟糕。
首先，在方法体中声明匿名片段类 - 但是，最好将此类与Activity类分开或使其成为静态内部类。
然后，你setRetainInstance(true)，它告诉Android不要在Activity旋转时销毁片段。这是针对其他用例的，你的情况并非如此。
我建议你阅读以下信息：
How to communicate Activity with Fragments
基本上，如果您按照Android规则玩游戏，大部分用户输入都将保存在设备轮换中，您可以开箱即用（参见上面的链接）。
当方向改变时，应用程序实际上被销毁并再次创建。所以你必须在某处保存状态，例如在instantState Bundle中
- 新编辑
我尝试了另一种方法，使用Button中的OnClickListener回调，并保持状态更改方向。
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// the method that is called from XML onClick
class MyDialogFragment extends DialogFragment {
@Override
public void onDestroyView() {
if (getDialog() != null && getRetainInstance())
getDialog().setDismissMessage(null);
super.onDestroyView();
}
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
setRetainInstance(true);
}
@Override
public Dialog onCreateDialog(Bundle state) {
DatePickerDialog dpd = new DatePickerDialog(getActivity(), new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int leto, int mesec, int dan) {
datY = leto;
datM = mesec;
datD = dan;
writeTheData();
}
}, datY, datM, datD);
return dpd;
}
}
newDF = new MyDialogFragment();
newDF.show(getFragmentManager(), null);
}
});
}