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我正在尝试使用片段创建具有主/明细流的应用程序。选择一个项目将打开一个细节片段，然后可以打开另一个片段并将其添加到后端堆栈。在主/细节流中切换片段
我已经重新命名了类来帮助说明他们做了什么。
public class ListOfDetails extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
}
//Callback method indicating that an item with the given ID was selected.
public void onItemSelected(String id) {
// Performing logic to determine what fragment to start omitted
if (ifTwoPanes()) {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
Intent newIntent = new Intent(this, SinglePaneFragmentWrapper.class);
newIntent.putExtra("id", id);
startActivity(newIntent);
}
}
// My attempt at making it possible to change displayed fragment from within fragments
public void changeDetailFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
transaction.addToBackStack(null);
transaction.replace(R.id.aContainer, fragment);
transaction.commit();
}
}
其中一个详细片段的示例。在不同情况下可能会创建许多不同的片段。
public class DetailFragmentType1 extends Fragment {
private ListOfDetails parent;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Activity a = getActivity();
if (a instanceof ListOfDetails) {
parent = (ListOfDetails) a;
}
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Button aButton = (Button) getActivity().findViewById(R.id.aButton);
aButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
parent.changeDetailFragment(new SubDetailFragment());
}
});
}
}
当电话，一个包装活动是用来装片段
public class SinglePaneFragmentWrapper extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Duplicate logic must be performed to start fragment
// Performing logic to determine what fragment to start omitted
String id = getIntent().getStringExtra("id");
if(id == "DetailFragmentType1") {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
...
}
}
}
什么是改变就是在这种情况下的细节窗格中打开该片段的正确方法？我的方法在使用两个窗格时感觉像是黑客，并且在仅使用一个窗格时不起作用，因为来自SinglePaneFragmentWrapper的getParent()返回null，使我无法呼叫parent.changeDetailFragment()。
这是一个复杂的问题，希望我解释得很好。让我知道如果我错过了什么。谢谢