我的MainActivity中有一个ViewPager（mainViewPager），它从包含另一个ViewPager（imageViewPager）和TextView的片段呈现。现在，imageViewPager从包含ImageView和按钮的另一个片段呈现。我在这个ImageView上设置了onClick监听器，它通过下方的按钮转换图像的全屏视图。现在点击这个按钮我想要返回到我的MainActivity，条件是在我输入的同一页面上与我在全屏中看到的相同图像。我能够获得相同的页面，但图像始终从0开始。
基本上我的层次结构如下：
MainActivity
--mainViewPager-->TaskFragment
--imageViewPager-->ImageFragment(contains only ImageView
--TextView(set text returned from MainActivity)
我的代码： 的 MainActivity.java
public class MainActivity extends FragmentActivity {
private ViewPager mViewPager;
private CustomPagerAdapter mPagerAdapter;
private int changedPosition;
private String[] vehicles = new String[]{"Audi Q7", "Honda Accord", "Hyundai i20", "Maruti Suzuki Swift", "Mahindra XUV 500",
"Swift Dzire", "Honda City", "Honda Civic", "Mercedez Benz", "Rolls Royce", "Ferrari"};
private String[][] vehicle_info = new String[][]{
{"http://www.hdwallpapers.in/walls/2010_abt_audi_q7_3_tdi_3-wide.jpg",
"http://www.hdwallpapers.in/walls/2010_mtm_audi_s5_cabrio_michelle_edition-wide.jpg",
"http://www.hdwallpapers.in/walls/2009_audi_tts_coupe_car-wide.jpg"},
{"http://automobiles.honda.com/images/2015/accord-sedan/exterior-gallery/2015-honda-accord-sedan-sport-exterior-side1.jpg",
"http://www.carprousa.com/wp-content/uploads/2015/01/HondaInterior-e1421978263126.jpg",
"http://www.carprousa.com/wp-content/uploads/2015/01/HondaInterior2-e1421978365916.jpg"},
...........
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mViewPager = (ViewPager)findViewById(R.id.mainViewPager);
mPagerAdapter = new CustomPagerAdapter(getSupportFragmentManager(), vehicles, vehicle_info);
mViewPager.setAdapter(mPagerAdapter);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 0) {
changedPosition = data.getIntExtra("CHANGED_POSITION", 0);
Log.i("POSITION 3:"," "+changedPosition);
TaskFragment fragment = new TaskFragment();
Bundle bundle = new Bundle();
bundle.putInt("IMAGE_POSITION", changedPosition);
fragment.setArguments(bundle);
}
}
}
activity_main.xml中
<android.support.v4.view.ViewPager
android:id="@+id/mainViewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</android.support.v4.view.ViewPager>
CustomPagerAdapter.java
public class CustomPagerAdapter extends FragmentStatePagerAdapter{
private String[] vehicles,selected_vehicle_info;
private String[][] vehicle_info;
public CustomPagerAdapter(FragmentManager fragmentManager,String[] vehicles,String[][] vehicle_info){
super(fragmentManager);
this.vehicles = vehicles;
this.vehicle_info = vehicle_info;
}
@Override
public Fragment getItem(int position) {
selected_vehicle_info = vehicle_info[position];
TaskFragment taskFragment = new TaskFragment();
Bundle bundle = new Bundle();
bundle.putString("ITEM",vehicles[position]);
bundle.putStringArray("ITEM_INFO",selected_vehicle_info);
taskFragment.setArguments(bundle);
return taskFragment;
}
@Override
public int getCount() {
return vehicles.length;
}
}
TaskFragment.java
public class TaskFragment extends Fragment {
private String vehicle;
private String[] vehicle_info;
private ViewPager imageViewPager;
private ImagePagerAdapter imagePagerAdapter;
private int changedImagePosition;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
vehicle = getArguments().getString("ITEM");
vehicle_info = getArguments().getStringArray("ITEM_INFO");
View view = inflater.inflate(R.layout.activity_task_fragment,container,false);
TextView messageTextView = (TextView) view.findViewById(R.id.textView);
messageTextView.setText(vehicle);
imageViewPager = (ViewPager)view.findViewById(R.id.imageViewPager);
imagePagerAdapter = new ImagePagerAdapter(getActivity(), vehicle_info);
imagePagerAdapter.notifyDataSetChanged();
imageViewPager.setAdapter(imagePagerAdapter);
imageViewPager.setCurrentItem(changedImagePosition);
return view;
}
private class ImagePagerAdapter extends PagerAdapter {
private Activity activity;
private String[] vehicle_info;
public ImagePagerAdapter(Activity activity,String[] vehicle_info){
this.activity = activity;
this.vehicle_info = vehicle_info;
}
@Override
public Object instantiateItem(ViewGroup container, final int position) {
LayoutInflater inflater = LayoutInflater.from(activity);
View view = inflater.inflate(R.layout.activity_image_fragment,container,false);
ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
Picasso.with(getContext()).load(vehicle_info[position]).into(imageView);
if(imageView.getParent()!=null)
((ViewGroup)imageView.getParent()).removeView(imageView);
((ViewPager) container).addView(imageView, 0);
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(activity, ImageInFullScreen.class);
intent.putExtra("IMAGES_URL", vehicle_info);
intent.putExtra("IMAGE_POSITION", position);
activity.startActivityForResult(intent, 0);
}
});
return imageView;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
@Override
public int getCount() {
return vehicle_info.length;
}
@Override
public void destroyItem(ViewGroup collection, int position, Object view) {
collection.removeView((View) view);
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
}
}
ImageInFullScreen.java
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent();
intent.putExtra("CHANGED_POSITION",changedImgPosition);
setResult(0,intent);}});
//和相同的适配器n。
答案 0 :(得分：0)
在哪里想要刷新视图，请输入以下代码
this.page_position = 0;
imagePagerAdapter.notifyDataSetChanged();
并在您的ImagePagerAdapter中覆盖以下函数 -
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
POSITION_NONE表示无论何时调用notifyDataSetChanged，适配器都会创建新视图而不是使用相同的视图。
这应该适用于我们的情况。
答案 1 :(得分：0)
我找到了一个问题的答案，问题是我的setCurrentItem（）不知道在TaskFragment的onCreateView（）中工作，所以我把它移到了Run方法Runnable接口的postAtTime（）nd然后它工作得很好。
这是我编辑过的代码。
<强> MainActivity.java `
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 0) {
claim_id = vehicleDetailsArrayList.get(changedPage).getClaimId();
//Retrieve value of position of last viewed image, before clicking the button
changedPosition = data.getIntExtra("CHANGED_POSITION", 0);
Log.i("POSITION 3:"," "+changedPosition);
if(changedPage > -1 && changedPage < vehicleDetailsArrayList.size()) {
addUpdateImagePositionInList(claim_id, changedPosition);
}
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
if (mViewPager.getAdapter() != null) {
mViewPager.getAdapter().notifyDataSetChanged();
}
}
}, 0);
}
}
public void addUpdateImagePositionInList(int claimId, int position){
for (int imageLength = 0; imageLength < imagePositionArrayList.size(); imageLength++)
{
if (claimId == (imagePositionArrayList.get(imageLength).getClaim_id()))
{
imagePositionArrayList.get(imageLength).setImagePosition(position);
return;
}
}
imagePositionArrayList.add(new ImagePosition(claimId, position));
}
public int getChangedImagePosition(int claimId){
for (int imageLength = 0; imageLength < imagePositionArrayList.size(); imageLength++)
{
if (claimId == (imagePositionArrayList.get(imageLength).getClaim_id()))
{
Log.i("POSITION123 "," ::"+ imagePositionArrayList.get(imageLength).getImagePosition() );
return imagePositionArrayList.get(imageLength).getImagePosition();
}
}
return 0;
}
`
<强> TaskFragment.java `
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
id = getArguments().getInt("ID");
vehicle = getArguments().getString("ITEM");
vehicle_info = getArguments().getStringArray("ITEM_INFO");
changedImagePosition = ((MainActivity)getActivity()).getChangedImagePosition(id);
View view = inflater.inflate(R.layout.task_fragment,container,false);
TextView messageTextView = (TextView) view.findViewById(R.id.textView);
messageTextView.setText(vehicle);
imageViewPager = (ViewPager)view.findViewById(R.id.imageViewPager);
imagePagerAdapter = new ImagePagerAdapter(getActivity(), vehicle_info);
imageViewPager.setAdapter(imagePagerAdapter);
/*The below code doesn't work
if (imageViewPager.getCurrentItem() != changedImagePosition) {
Log.i("POSITION current", ":" + imageViewPager.getCurrentItem());
Log.i("POSITION changed", " :"+ changedImagePosition);
setCurrentItem = true;
imageViewPager.setCurrentItem(changedImagePosition, false);
Log.i("POSITION getCurrent", " :" + imageViewPager.getCurrentItem());
}
*/
new Handler().postAtTime(new Runnable() {
@Override
public void run() {
if (imageViewPager.getAdapter() != null) {
imageViewPager.getAdapter().notifyDataSetChanged();
imageViewPager.setCurrentItem(changedImagePosition);
}
}
},0);
return view;
}
`