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[英]Restore Android GridView after screen orientation change (without reloading it)
[英]Android: fragment restore after screen orientation change
我從片段開始,現在面臨一個問題。 屏幕旋轉后,我將無法恢復片段。 我的應用程序如下所示:在橫向視圖上,左側區域有一個按鈕,該按鈕在右側區域更新了一個標簽。 如果是縱向模式,我將導航到一個新活動。 但是,旋轉后我不會保持片段狀態。 代碼如下:
左側區域片段:
public class ListFragment extends Fragment implements OnClickListener {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_list, container, false);
Button button = (Button) view.findViewById(R.id.button1);
button.setOnClickListener(this);
return view;
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button1:
updateDetail();
break;
}
}
public void updateDetail() {
String newTime = String.valueOf(System.currentTimeMillis());
DetailFragment fragment = (DetailFragment) getFragmentManager()
.findFragmentById(R.id.detailFragment);
if (fragment != null && fragment.isInLayout()) {
fragment.setText(newTime);
} else {
Intent intent = new Intent(getActivity().getApplicationContext(),
DetailActivity.class);
intent.putExtra("value", newTime);
startActivity(intent);
}
}
}
正確的區域活動:
public class DetailActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
finish();
return;
}
if (savedInstanceState == null) {
setContentView(R.layout.activity_detail);
Bundle extras = getIntent().getExtras();
if (extras != null) {
String s = extras.getString("value");
TextView view = (TextView) findViewById(R.id.detailsText);
view.setText(s);
}
}
}
}
右側區域片段:
public class DetailFragment extends Fragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater
.inflate(R.layout.fragment_detail, container, false);
return view;
}
public void setText(String item) {
TextView view = (TextView) getView().findViewById(R.id.detailsText);
view.setText(item);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
FragmentManager fm = getFragmentManager();
DetailFragment fragment = (DetailFragment)fm.findFragmentById(R.id.detailFragment);
if (fragment == null) {
fragment = new DetailFragment();
fragment.setTargetFragment(this, 0);
fm.beginTransaction().add(R.id.detailFragment, fragment).commit();
}
}
}
我可能做錯了什么?
你可以使用捆綁的幾個選項對夫婦的方法來保存和恢復片段的狀態。
或者,您可以使用setRetainInstance方法:
onCreate(Bundle save)
{
super.onCreate(save);
setRetainInstance(true);
}
請記住,setRetainInstance方法不適用於Backstack中的片段。
@Override
public void onConfigurationChanged(Configuration newConfig) {
int orientation = getResources().getConfiguration().orientation;
switch (orientation) {
case Configuration.ORIENTATION_LANDSCAPE:
getSupportFragmentManager().beginTransaction().replace(R.id.detailFragment, new DetailFragment()).commitAllowingStateLoss();
getSupportFragmentManager().beginTransaction().remove(new DetailFragment()).commitAllowingStateLoss();
break;
case Configuration.ORIENTATION_PORTRAIT:
getSupportFragmentManager().beginTransaction().replace(R.id.detailFragment, new DetailFragment()).commitAllowingStateLoss();
getSupportFragmentManager().beginTransaction().remove(new DetailFragment()).commitAllowingStateLoss();
break;
}
super.onConfigurationChanged(newConfig);
}
您可以檢查onConfigurationChange
並確保做你的片段狀態不丟commitAllowingStateLoss
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