Question

我在一项活动中有一个searchView。搜索过滤器工作得很好，除了有一个我不知道如何解决的问题。你看，当我从纵向到横向改变方向时，它会导致错误，我不知道我做错了什么。那么有谁能告诉我我做错了什么？

这是代码

 ArrayList<petbook_getItem> bookItem=new ArrayList<>();
RecyclerView petbook;
petbook_adapter adapter;
LinearLayoutManager linearLayoutManager;
TextView pet_title;
private static Parcelable pet_recycler;
SearchView searchView;
private static final String SEARCH_KEY = "search";
String mSearchString;
MenuItem searchItem;

if(savedInstanceState != null){
           mSearchString=savedInstanceState.getString(SEARCH_KEY);
        }

        pet_title=(TextView)findViewById(R.id.pet_book_title);
        petbook=(RecyclerView)findViewById(R.id.pet_book_pet);
        navbot=(BottomNavigationView) findViewById(R.id.petbook_navbot);
        toolbar=(Toolbar)findViewById(R.id.petbook_toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDisplayShowTitleEnabled(false);
        toolbar.setTitle("");
        linearLayoutManager=new LinearLayoutManager(this);
        petbook.setHasFixedSize(true);
        petbook.setLayoutManager(linearLayoutManager);
        refresh();
        disableShiftMode(navbot);
petbook.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                if (dy > 0 && navbot.isShown()) {
                    navbot.setVisibility(View.GONE);
                } else if (dy < 0 ) {
                    navbot.setVisibility(View.VISIBLE);

                }
            }
        });
    }

 @Override
    public boolean onOptionsItemSelected(MenuItem item) {
       if(item.getItemId()==android.R.id.home){
           {
               finish();
           }

       }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onCreateOptionsMenu(final Menu menu) {
        MenuInflater menuInflater= getMenuInflater();
        menuInflater.inflate(R.menu.petbook_searck,menu);
        searchItem=menu.findItem(R.id.pet_book_search_mode);
        searchView =(SearchView)MenuItemCompat.getActionView(searchItem);
        if (mSearchString != null && !mSearchString.isEmpty()) {
            searchItem.expandActionView();
            searchView.setQuery(mSearchString, true);
            searchView.clearFocus();
        }
        search(searchView);
        MenuItemCompat.setOnActionExpandListener(searchItem, new MenuItemCompat.OnActionExpandListener() {
            @Override
            public boolean onMenuItemActionExpand(MenuItem item) {
                pet_title.setVisibility(View.INVISIBLE);
                return true;
            }

            @Override
            public boolean onMenuItemActionCollapse(MenuItem item) {
                pet_title.setVisibility(View.VISIBLE);
                return true;
            }
        });
        return true;
    }
    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mSearchString = searchView.getQuery().toString();
        outState.putString(SEARCH_KEY, mSearchString);
    }
   @Override
    public void onPause() {
        super.onPause();
        pet_recycler = petbook.getLayoutManager().onSaveInstanceState();

    }
    @Override
    public void onResume()
    {  //
        super.onResume();
        if (mSearchString != null && !mSearchString.isEmpty()) {
            searchItem.expandActionView();
            searchView.setQuery(mSearchString, true);
            searchView.clearFocus();
            adapter.filterSearch(newList);
            adapter.notifyDataSetChanged();
        }
        else
        {
            bookItem.clear();
            refresh();
        }
        petbook.getLayoutManager().onRestoreInstanceState(pet_recycler);
    }

    public void search(android.support.v7.widget.SearchView search)
    {
        search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                newText=newText.toLowerCase();
                newList=new ArrayList<>();
                for(petbook_getItem items : bookItem){
                    String pets=items.getPet_name().toLowerCase();
                    if(pets.contains(newText))
                        newList.add(items);
                }
                adapter.filterSearch(newList);
                adapter.notifyDataSetChanged();
                return true;
            }
        });
    }

这是发生的错误

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: petguide.com.petguide101, PID: 25230
              java.lang.RuntimeException: Unable to resume activity {petguide.com.petguide101/petguide.com.petguide101.petbook.pet_book}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.SearchView.setQuery(java.lang.CharSequence, boolean)' on a null object reference
                  at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3226)
                  at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3257)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2600)
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4210)
                  at android.app.ActivityThread.access$900(ActivityThread.java:178)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1476)
                  at android.os.Handler.dispatchMessage(Handler.java:111)
                  at android.os.Looper.loop(Looper.java:194)
                  at android.app.ActivityThread.main(ActivityThread.java:5631)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at java.lang.reflect.Method.invoke(Method.java:372)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.SearchView.setQuery(java.lang.CharSequence, boolean)' on a null object reference
                  at petguide.com.petguide101.petbook.pet_book.onResume(pet_book.java:197)
                  at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1267)
                  at android.app.Activity.performResume(Activity.java:6178)
                  at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3211)
                  at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3257) 
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2600) 
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4210) 
                  at android.app.ActivityThread.access$900(ActivityThread.java:178) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1476) 
                  at android.os.Handler.dispatchMessage(Handler.java:111) 
                  at android.os.Looper.loop(Looper.java:194) 
                  at android.app.ActivityThread.main(ActivityThread.java:5631) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at java.lang.reflect.Method.invoke(Method.java:372) 
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)

Answer 1

在这里！代码中的所有内容对我来说都很好在项目清单中的活动定义中使用此属性标记。

android:configChanges="keyboardHidden|orientation|screenSize"

这将停止屏幕旋转上的自动活动重启问题。还有更多方法可以做到这一点 check out THIS for more

更改方向时如何保存searchView的状态

1 个答案: