Java onCreate、onResume&;onPause保存回收器查看旋转位置?
无论我选择遵循stackoverflow中的哪个示例,我都没有得到期望的结果 我想在旋转时保存recyclerView滚动位置,但选择的保存状态Java onCreate、onResume&;onPause保存回收器查看旋转位置?,java,android,Java,Android,无论我选择遵循stackoverflow中的哪个示例,我都没有得到期望的结果 我想在旋转时保存recyclerView滚动位置,但选择的保存状态(最受欢迎的电影、最喜爱的电影和流行电影)似乎会覆盖该状态,以便从屏幕顶部重新加载所需的选择 例如,在底部的一半或全部,然后旋转它保存选择类型(例如,旋转前显示的内容),但从开始重新加载(顶部(不需要,我需要保持在同一位置)) 我的代码: 主要活动 public class MainActivity extends AppCompatActivity {
(最受欢迎的电影、最喜爱的电影和流行电影)
似乎会覆盖该状态,以便从屏幕顶部重新加载所需的选择
例如,在底部的一半或全部,然后旋转它保存选择类型(例如,旋转前显示的内容),但从开始重新加载(顶部(不需要,我需要保持在同一位置))
我的代码:
主要活动
public class MainActivity extends AppCompatActivity {
public static final String TAG = MainActivity.class.getSimpleName();
public static final int POP = 1;
public static final int TOP = 2;
public static final int FAV = 3;
int selection = -1;
private RecyclerView rv;
private MovieAdapter adapter;
private MovieDbHelper dbHelper;
private FrameLayout frame;
private AppCompatActivity activity = MainActivity.this;
private static final String BUNDLE_RECYCLER_LAYOUT = "classname.recycler.layout";
public static int index = -1;
public static int top = -1;
int currentVisiblePosition;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (!isOnline()) {
Toast.makeText(activity, "No Connection", Toast.LENGTH_SHORT).show();
} else {
initControls();
dbHelper = new MovieDbHelper(activity);
if (savedInstanceState != null) {
selection = savedInstanceState.getInt("selection");
//Now just load the list
switch (selection) {
case POP:
loadJSON(POP);
break;
case TOP:
loadJSON(TOP);
break;
case FAV:
initializeFavorites();
break;
case -1:
initializeViews();
break;
}
} else {
initializeViews();
}
}
}
private void initControls() {
rv = findViewById(R.id.rv_main);
adapter = new MovieAdapter(this, new ArrayList<Movie>());
rv.setLayoutManager(new GridLayoutManager(this, ScreenSizeUtil.calculateNoOfColumns(this)));
rv.setItemAnimator(new DefaultItemAnimator());
rv.setAdapter(adapter);
dbHelper = new MovieDbHelper(activity);
frame = findViewById(R.id.frame);
checkSortOrder();
}
private void initializeViews() {
Toast.makeText(this, "Change sort order via the Settings Menu....", Toast.LENGTH_SHORT).show();
}
private void initializeFavorites() {
getAllFavorites();
}
private boolean isOnline() {
ConnectivityManager cm =
(ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
return netInfo != null && netInfo.isConnectedOrConnecting();
}
private void loadJSON(int listType) {
try {
if (BuildConfig.THE_MOVIE_DB_API_TOKEN.isEmpty()) {
Toast.makeText(this, "Error with Api Key....", Toast.LENGTH_SHORT).show();
return;
}
Client Client = new Client();
Service apiService =
Client.getClient().create(Service.class);
Call<MovieResponse> call = listType==TOP? apiService
.getMovies("top_rated",BuildConfig.THE_MOVIE_DB_API_TOKEN): apiService.getMovies("popular",BuildConfig.THE_MOVIE_DB_API_TOKEN) ;
call.enqueue(new Callback<MovieResponse>() {
@Override
public void onResponse(Call<MovieResponse> call, final Response<MovieResponse> response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
List<Movie> movies = response.body().getResults();
adapter.setMovieList(movies);
rv.scrollToPosition(0);
}
});
}
@Override
public void onFailure(Call<MovieResponse> call, Throwable t) {
Log.d("Error", t.getMessage());
Toast.makeText(MainActivity.this, "Error with Data!", Toast.LENGTH_SHORT).show();
}
});
} catch (Exception e) {
Log.d("Error", e.getMessage());
Toast.makeText(this, e.toString(), Toast.LENGTH_SHORT).show();
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelable(BUNDLE_RECYCLER_LAYOUT, rv.getLayoutManager().onSaveInstanceState());
}
private void checkSortOrder(){
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String sortOrder = preferences.getString(
this.getString(R.string.pref_sort_order_key),
this.getString(R.string.pref_most_popular)
);
if (sortOrder.equals(this.getString(R.string.pref_most_popular))) {
Log.d(TAG, "Sorting by most popular");
loadJSON(POP);
} else if (sortOrder.equals(this.getString(R.string.pref_highest_rated))){
Log.d(TAG, "Sorting by Top rated");
loadJSON(TOP);
} else{
Log.d(TAG, "Sorting by Favorites");
initializeFavorites();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
Intent intent = new Intent(this, SettingsActivity.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onResume() {
super.onResume();
(rv.getLayoutManager()).scrollToPosition(currentVisiblePosition);
currentVisiblePosition = 0;
}
@Override
public void onPause() {
super.onPause();
currentVisiblePosition = 0;
currentVisiblePosition = ((LinearLayoutManager)rv.getLayoutManager()).findFirstCompletelyVisibleItemPosition();}
private void getAllFavorites() {
new AsyncTask<Void, Void, ArrayList<Movie>>() {
@Override
protected ArrayList<Movie> doInBackground(Void... voids) {
return new ArrayList<>(dbHelper.getAllFavorites());
}
@Override
protected void onPostExecute(ArrayList<Movie> aVoid) {
super.onPostExecute(aVoid);
adapter.setMovieList(aVoid);
}
}.execute();
}
}
public类MainActivity扩展了AppCompatActivity{
公共静态最终字符串标记=MainActivity.class.getSimpleName();
公共静态最终int POP=1;
公共静态最终int TOP=2;
公共静态最终整数FAV=3;
整数选择=-1;
私人回收车;
私人电影适配器;
私人电影助手;
专用框架布局框架;
私有AppCompativeActivity=MainActivity.this;
私有静态最终字符串包\u RECYCLER\u LAYOUT=“classname.RECYCLER.LAYOUT”;
公共静态整数指数=-1;
公共静态int top=-1;
int-currentVisiblePosition;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
如果(!isOnline()){
Toast.makeText(活动“无连接”,Toast.LENGTH_SHORT).show();
}否则{
initControls();
dbHelper=新的MovieDbHelper(活动);
如果(savedInstanceState!=null){
selection=savedInstanceState.getInt(“selection”);
//现在只需加载列表
开关(选择){
个案流行:
loadJSON(POP);
打破
案例顶部:
loadJSON(顶部);
打破
案例FAV:
初始化为vorites();
打破
案例1:
初始化视图();
打破
}
}否则{
初始化视图();
}
}
}
私有控件(){
rv=findViewById(R.id.rv_main);
adapter=new MovieAdapter(这个,new ArrayList());
rv.setLayoutManager(新的GridLayoutManager(此,ScreenSizeUtil.CalculateNofColumns(此));
rv.setItemAnimator(新的DefaultItemAnimator());
rv.设置适配器(适配器);
dbHelper=新的MovieDbHelper(活动);
frame=findviewbyd(R.id.frame);
checkSortOrder();
}
private void initializeViews(){
Toast.makeText(这是“通过设置菜单更改排序顺序…”),Toast.LENGTH_SHORT.show();
}
私有void initializeFavorites(){
getAllFavorites();
}
私有布尔isOnline(){
连接管理器cm=
(ConnectionManager)getApplicationContext().getSystemService(Context.CONNECTIVITY_服务);
NetworkInfo netInfo=cm.getActiveNetworkInfo();
返回netInfo!=null&&netInfo.isConnectedOrConnecting();
}
私有void loadJSON(int-listType){
试一试{
if(BuildConfig.THE\u MOVIE\u DB\u API\u TOKEN.isEmpty()){
Toast.makeText(这是“Api键出错…”,Toast.LENGTH_SHORT.show();
返回;
}
客户端=新客户端();
服务业=
Client.getClient().create(Service.class);
Call Call=listType==TOP?apiService
.getMovies(“最高评级”,BuildConfig.THE_MOVIE\u DB\u API\u令牌):apiService.getMovies(“流行”,BuildConfig.THE_MOVIE\u DB\u API\u令牌);
call.enqueue(新回调(){
@凌驾
公共void onResponse(呼叫、最终响应){
runOnUiThread(新的Runnable(){
@凌驾
公开募捐{
List movies=response.body().getResults();
adapter.setMovieList(电影);
右心室位置(0);
}
});
}
@凌驾
失败时公共无效(调用调用,可丢弃的t){
Log.d(“Error”,t.getMessage());
Toast.makeText(MainActivity.this,“数据错误!”,Toast.LENGTH_SHORT.show();
}
});
}捕获(例外e){
Log.d(“错误”,例如getMessage());
Toast.makeText(例如toString(),Toast.LENGTH_SHORT).show();
}
}
@凌驾
SaveInstanceState上的公共无效(束超出状态){
super.onSaveInstanceState(超出状态);
outState.putParcelable(BUNDLE\u RECYCLER\u布局,rv.getLayoutManager().onSaveInstanceState());
}
私有无效检查排序器(){
SharedReferences preferences=PreferenceManager.GetDefaultSharedReferences(此);
String sortOrder=preferences.getString(
这个.getString(R.string.pref\u sort\u order\u键),
this.getString(R.string.pref\u最流行)
);
if(sortOrder.equals(this.getString(R.string.pref_most_popular))){
Log.d(标签,“按最流行的排序”);
loadJSON(POP);
}else if(sortOrder.equals(this.getString(R.string.pref\u highest\u rated))){
Log.d(标签“按最高评级排序”);
loadJSON(顶部);
}否则{
Log.d(标记“按收藏夹排序”);
初始化为vorites();
}
}
@凌驾
公共布尔onCreateOptions菜单(菜单)