MainActivity代码：
public class MainActivity extends AppCompatActivity implements OnColorButtonListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public void onColorClick(int color) {
Fragment fragment = null;
switch (color) {
case 0:
fragment = new RedFragment();
break;
case 1:
fragment = new BlueFragment();
break;
}
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_ex, fragment).commit();
}
}
RedFragment代码：
public class RedFragment extends Fragment implements FlowerAdapter.FlowerClickListener {
private SwipeRefreshLayout swipeContainer_red;
private RecyclerView mRecyclerView;
private RestManager mRestManager;
private FlowerAdapter mFlowerAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_red, null);
swipeContainer_red = (SwipeRefreshLayout) view.findViewById(R.id.swipeContainer_red);
swipeContainer_red.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
mRestManager = new RestManager();
Call<List<Flower>> listCall = mRestManager.getmFlowerApiService(getActivity()).getAllFlowers();
listCall.enqueue(new Callback<List<Flower>>() {
@Override
public void onResponse(Call<List<Flower>> call, Response<List<Flower>> response) {
if (response.isSuccessful()) {
mFlowerAdapter.clear();
List<Flower> flowerList = response.body();
for(int i =0; i<flowerList.size(); i++) {
Flower flower = flowerList.get(i);
mFlowerAdapter.addFlower(flower);
}
swipeContainer_red.setRefreshing(false);
}
}
@Override
public void onFailure(Call<List<Flower>> call, Throwable t) {
}
});
}
});
configViews(view);
return view;
}
private void configViews(View view) {
mRecyclerView = (RecyclerView) view.findViewById(R.id.rv_flower_red);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setRecycledViewPool(new RecyclerView.RecycledViewPool());
mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity().getApplicationContext(), 3));
mFlowerAdapter = new FlowerAdapter(this);
mRecyclerView.setAdapter(mFlowerAdapter);
}
@Override
public void onClick(int position) {
}
}
当我阅读RedFragment的内容时，我转到蓝色的Fragment，然后回到RedFragment，RedFragment丢失了以前在RedFragment上的所有内容。
我希望当我跳下另一个Fragment时RedFragment不会被更改。
题
当我看到其他碎片时如何使RedFragment设置不变？
编辑//RowFragment.java
public class RowFragment extends Fragment implements View.OnClickListener {
private OnColorButtonListener onColorButtonListener;
public RowFragment() {
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
onColorButtonListener = (OnColorButtonListener) context;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_row, container, false);
view.findViewById(R.id.v_red).setOnClickListener(this);
view.findViewById(R.id.v_blue).setOnClickListener(this);
return view;
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.v_red:
onColorButtonListener.onColorClick(0);
break;
case R.id.v_blue:
onColorButtonListener.onColorClick(1);
break;
}
我修改的代码：MainActivity的onColorClick方法
@Override
public void onColorClick(int color) {
Fragment frag = null;
switch (color) {
case 0:
frag = getSupportFragmentManager().findFragmentByTag("red");
if(frag==null){
frag=new RedFragment();
getSupportFragmentManager().beginTransaction().add(R.id.fragment_ex, frag, "red").commit();
}
break;
case 1:
frag = getSupportFragmentManager().findFragmentByTag("blue");
if(frag==null){
frag=new BlueFragment();
getSupportFragmentManager().beginTransaction().add(R.id.fragment_ex, frag, "blue").commit();
}
break;
}
getSupportFragmentManager().beginTransaction().show(frag).commit();
}
但是该代码存在问题，当第一次单击时，它可以正常工作，但是第二次单击相同的颜色，它将不再起作用。我应该怎么解决呢？
最佳答案
而不是每次尝试newFragment
Fragment frag=getSupportFragmentManager().findFragmentByTag(TAG);
if(frag==null){
frag=new Fragment();
}
在添加片段时，请指定一个标签，以便以后可以重新访问并重新访问。
您也可以使用
setRetainInstance方法，并在onCreate中设置内容。