我有全屏浏览图像的活动(比如画廊)。在这个活动中,我有离屏限制为 6 的 ViewPager。我将TouchImageView用于我的图像。问题是,当我第一次缩放图像并滑动到另一张照片时,我想在返回时看到未缩放的照片。TouchImageView 具有 resetZoom() 功能,但如何从 FragmentStatePageAdapter 或 ViewPager 获取屏幕外页面视图?这是我的活动代码:
public class ImageSlidesActivity extends FragmentActivity implements ViewPager.OnPageChangeListener {
final int PAGE_LIMIT = 6;
final int PAGE_MARGIN = 8;
long userID;
long deviceID;
String key;
String[] mAttachments;
ImageSlidesAdapter mAdaper;
ViewPager mPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
setContentView(R.layout.activity_image_slides);
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
//actionBar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#33ffffff")));
Intent intent = getIntent();
mAttachments = intent.getStringArrayExtra("attachments");
int position = intent.getIntExtra("position", 0);
SharedPreferences pref = getApplicationContext().getSharedPreferences("authData", 0);
key = pref.getString("key", null);
userID = pref.getLong("userID", 0);
deviceID = pref.getLong("deviceID", 0);
setPageIndicator(position);
mAdaper = new ImageSlidesAdapter(getSupportFragmentManager(), mAttachments);
final View container = findViewById(R.id.container);
container.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getActionBar().hide();
container.setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
}
});
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(mAdaper);
mPager.setOnPageChangeListener(this);
mPager.setOffscreenPageLimit(PAGE_LIMIT);
mPager.setCurrentItem(position-1);
/* cause bug with the white strip
final float density = getResources().getDisplayMetrics().density;
mPager.setPageMargin((int) (PAGE_MARGIN * density + 0.5f));
mPager.setPageMarginDrawable(android.R.color.black);
*/
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
//getMenuInflater().inflate(R.menu.image_slides, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == android.R.id.home) {
onBackPressed();
}
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
setPageIndicator(position+1);
}
@Override
public void onPageScrollStateChanged(int state) {
}
private void setPageIndicator(int page) {
setTitle(Integer.toString(page) + "/" + Integer.toString(mAttachments.length));
}
/**
* A fragment containing zoomable image.
*/
public static class ShowImageFragment extends Fragment {
String mAlias;
long mUserId;
long mDeviceId;
String mKey;
TouchImageView mImage;
static ShowImageFragment newInstance(String alias, long userId, long deviceId,
String key) {
ShowImageFragment f = new ShowImageFragment();
Bundle args = new Bundle();
args.putString("alias", alias);
args.putLong("userID", userId);
args.putLong("deviceID", deviceId);
args.putString("key", key);
f.setArguments(args);
return f;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle bundle = getArguments();
mAlias = bundle.getString("alias");
mUserId = bundle.getLong("userID");
mDeviceId = bundle.getLong("deviceID");
mKey = bundle.getString("key");
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_image_slides, container, false);
mImage = (TouchImageView) rootView.findViewById(R.id.imageView);
final ProgressBar prBar = (ProgressBar) rootView.findViewById(R.id.progressBar);
new AsyncTask<Void, Void, Bitmap>() {
@Override
protected Bitmap doInBackground(Void... voids) {
try {
String[] links = API.getImageLinkByAlias(mAlias, mUserId,
mDeviceId, mKey);
return ImageLoader.getInstance().loadImageSync(links[1]);
} catch (Exception e) {
// TODO: handle exceptions
e.printStackTrace();
cancel(true);
return null;
}
}
@Override
protected void onPostExecute(Bitmap bitmap) {
prBar.setVisibility(View.GONE);
if (bitmap == null) { return; }
mImage.setImageBitmap(bitmap);
mImage.setVisibility(View.VISIBLE);
mImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (getActivity().getActionBar().isShowing()) {
getActivity().getActionBar().hide();
} else {
getActivity().getActionBar().show();
}
}
});
}
}.execute();
return rootView;
}
}
public class ImageSlidesAdapter extends FragmentStatePagerAdapter {
private String[] mAliases;
public ImageSlidesAdapter(android.support.v4.app.FragmentManager fm, String[] aliases) {
super(fm);
mAliases = aliases;
}
@Override
public android.support.v4.app.Fragment getItem(int position) {
return ShowImageFragment.newInstance(mAliases[position], userID, deviceID, key);
}
@Override
public int getCount() {
return mAliases.length;
}
}
}