我正在尝试仅使用片段进行构建。该应用程序以一个 Activity 空白打开,该空白只有一个 ActionBar 在单击汉堡包图标时它会打开一个抽屉,为您提供一个菜单选项。
单击其中一个菜单项后,它会打开具有回收器/卡片视图的第一个片段。单击其中一张卡片后,它会打开一个新片段,其中包含所选卡片的更多详细信息。
现在的问题是细节片段显示主页图标,因为我启用了 setDisplayHomeAsUpEnabled(true) 但是当我点击后退箭头时它什么也没做。硬件后退按钮确实将我带回到上一个(回收器/卡片视图)片段。我在详细信息片段中也有 setHasOptionsMenu(true) 。我将日志标签放在任何地方,以查看主页按钮何时做出反应,但什么也没有。
希望有人能帮帮我。
活动:
public class AppStart extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
ActionBarDrawerToggle actionBarDrawerToggle;
final String TAG = "AppSart: onBackPressed";
final String TAG1 = "AppSart: resetActionBar";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_app_start);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
}
@Override
public void onBackPressed() {
int stack = getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG,Integer.toString(stack));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return false;
}
public void resetActionBar(boolean childAction)
{
Log.d(TAG1,Boolean.toString(childAction));
if (childAction) {
actionBarDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
} else {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
actionBarDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
}
回收器片段:
public class ProductFragment extends Fragment {
final String TAG1 = "ProdFrag: onCreate";
final String TAG2 = "ProdFrag: onCreateView";
final String TAG3 = "ProdFrag: onResume";
final String TAG6 = "ProdFrag: ActionSetting";
final String TAG7 = "ProdFrag: home";
public ProductFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG1,Integer.toString(stack));
boolean canback = stack>0;
((AppStart)getActivity()).resetActionBar(canback);
}
@Override
public void onResume() {
super.onResume();
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG3,Integer.toString(stack));
boolean canback = stack>0;
((AppStart)getActivity()).resetActionBar(canback);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view=inflater.inflate(R.layout.fragment_product,container,false);
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG2,Integer.toString(stack));
return view;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// Inflate the menu; this adds items to the action bar if it is present.
inflater.inflate(R.menu.toolbar_menu, menu);
super.onCreateOptionsMenu(menu,inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
switch (item.getItemId()) {
case R.id.action_settings:
Log.d(TAG6,Integer.toString(stack));
return true;
default:
break;
}
return false;
}
}
细节片段:
public class ProductTabsFragment extends Fragment {
final String TAG1 = "TabFrag: onCreate";
final String TAG2 = "TabFrag: onResume";
final String TAG3 = "TabFrag: ActionSettings";
final String TAG4 = "TabFrag: home";
final String TAG5 = "TabFrag: onBckStkChng";
final String TAG6 = "TabFrag: onNavigateUp";
public ProductTabsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG1,Integer.toString(stack));
boolean canback = stack>0;
((AppStart)getActivity()).resetActionBar(canback);
}
@Override
public void onResume() {
super.onResume();
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
Log.d(TAG2,Integer.toString(stack));
boolean canback = stack>0;
((AppStart)getActivity()).resetActionBar(canback);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_product_tabs, container, false);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// Inflate the menu; this adds items to the action bar if it is present.
inflater.inflate(R.menu.toolbar_menu, menu);
super.onCreateOptionsMenu(menu,inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int stack = getActivity().getSupportFragmentManager().getBackStackEntryCount();
switch (item.getItemId()) {
case R.id.action_settings:
Log.d(TAG3,Integer.toString(stack));
return true;
case android.R.id.home:
Log.d(TAG4,Integer.toString(stack));
//getActivity().onBackPressed();
return true;
default:
break;
}
return false;
}
}
这也是回收器适配器中的代码,用于单击卡片以加载详细片段:
cvProduct.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
ProductTabsFragment productTabsFragment = new ProductTabsFragment();
AppCompatActivity activity = (AppCompatActivity) view.getContext();
FragmentTransaction transaction = activity.getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container,productTabsFragment);
transaction.addToBackStack(null);
transaction.commit();
}
});