问题
I'm testing an android project (http://developer.android.com/training/animation/screen-slide.html) and I have an error in one class.
/*
* Copyright 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.screensidetest2;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Intent;
import android.os.Bundle;
import android.support.v13.app.FragmentActivity;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.app.NavUtils;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;
/**
* Demonstrates a "screen-slide" animation using a {@link ViewPager}. Because {@link ViewPager}
* automatically plays such an animation when calling {@link ViewPager#setCurrentItem(int)}, there
* isn't any animation-specific code in this sample.
*
* <p>This sample shows a "next" button that advances the user to the next step in a wizard,
* animating the current screen out (to the left) and the next screen in (from the right). The
* reverse animation is played when the user presses the "previous" button.</p>
*
* @see ScreenSlidePageFragment
*/
public class ScreenSlideActivity extends FragmentActivity {
/**
* The number of pages (wizard steps) to show in this demo.
*/
private static final int NUM_PAGES = 5;
/**
* The pager widget, which handles animation and allows swiping horizontally to access previous
* and next wizard steps.
*/
private ViewPager mPager;
/**
* The pager adapter, which provides the pages to the view pager widget.
*/
private PagerAdapter mPagerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen_slide);
// Instantiate a ViewPager and a PagerAdapter.
mPager = (ViewPager) findViewById(R.id.pager);
mPagerAdapter = new ScreenSlidePagerAdapter(getFragmentManager());
mPager.setAdapter(mPagerAdapter);
mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// When changing pages, reset the action bar actions since they are dependent
// on which page is currently active. An alternative approach is to have each
// fragment expose actions itself (rather than the activity exposing actions),
// but for simplicity, the activity provides the actions in this sample.
invalidateOptionsMenu();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.activity_screen_slide, menu);
menu.findItem(R.id.action_previous).setEnabled(mPager.getCurrentItem() > 0);
// Add either a "next" or "finish" button to the action bar, depending on which page
// is currently selected.
MenuItem item = menu.add(Menu.NONE, R.id.action_next, Menu.NONE,
(mPager.getCurrentItem() == mPagerAdapter.getCount() - 1)
? R.string.action_finish
: R.string.action_next);
item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// Navigate "up" the demo structure to the launchpad activity.
// See http://developer.android.com/design/patterns/navigation.html for more.
NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
return true;
case R.id.action_previous:
// Go to the previous step in the wizard. If there is no previous step,
// setCurrentItem will do nothing.
mPager.setCurrentItem(mPager.getCurrentItem() - 1);
return true;
case R.id.action_next:
// Advance to the next step in the wizard. If there is no next step, setCurrentItem
// will do nothing.
mPager.setCurrentItem(mPager.getCurrentItem() + 1);
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A simple pager adapter that represents 5 {@link ScreenSlidePageFragment} objects, in
* sequence.
*/
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return ScreenSlidePageFragment.create(position);
}
@Override
public int getCount() {
return NUM_PAGES;
}
}
}
I added the jar in libs (I have both, v13 and v4), but the error still persists. Thank you.
EDIT: After changing v13 to v4, a lot of errors are disappearing remaining only 2.
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm) {
super(fm);
}
super(fm); The constructor FragmentStatePageAdapter(FragmentManager) is undefined.
and
public Fragment getItem(int position) {
return ScreenSlidePageFragment.create(position);
}
public Fragment getItem(int position) - the return type is incompatible with FragmentStatePageAdapter.getItem(int).
回答1:
Change the "import android.support.v13.app.FragmentActivity" to "import android.support.v4.app.FragmentActivity"
For the undefined part, try this syntax:
public class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter (android.support.v4.app.FragmentManager fm) {
super(fm);
}
and:
@Override
public android.support.v4.app.Fragment getItem(int position) {
return ScreenSlidePagerAdapter.create(position);
}
Original suggestion: Have you added the libraries to your build path? Just right-click on the project and the menu item "Java Build Path" will be listed. Select this and add the libraries to your path.
回答2:
I was blocked on this for a while and just managed to fix it,
Try using getSupportFragmentManager() instead of getFragmentManager().
回答3:
Here is a full code for further reference
package com.team.test;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.app.NavUtils;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;
/**
* Demonstrates a "screen-slide" animation using a {@link ViewPager}. Because
* {@link ViewPager} automatically plays such an animation when calling
* {@link ViewPager#setCurrentItem(int)}, there isn't any animation-specific
* code in this sample.
*
* <p>
* This sample shows a "next" button that advances the user to the next step in
* a wizard, animating the current screen out (to the left) and the next screen
* in (from the right). The reverse animation is played when the user presses
* the "previous" button.
* </p>
*
* @see ScreenSlidePageFragment
*/
public class MenuActivity extends FragmentActivity {
/**
* The number of pages (wizard steps) to show in this demo.
*/
private static final int NUM_PAGES = 6;
/**
* The pager widget, which handles animation and allows swiping horizontally
* to access previous and next wizard steps.
*/
private ViewPager mPager;
/**
* The pager adapter, which provides the pages to the view pager widget.
*/
private PagerAdapter mPagerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.activity_screen_slide);
// Instantiate a ViewPager and a PagerAdapter.
mPager = (ViewPager) findViewById(R.id.pager);
mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
mPager.setAdapter(mPagerAdapter);
mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// When changing pages, reset the action bar actions since they
// are dependent
// on which page is currently active. An alternative approach is
// to have each
// fragment expose actions itself (rather than the activity
// exposing actions),
// but for simplicity, the activity provides the actions in this
// sample.
invalidateOptionsMenu();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.activity_screen_slide, menu);
menu.findItem(R.id.action_previous).setEnabled(
mPager.getCurrentItem() > 0);
// Add either a "next" or "finish" button to the action bar, depending
// on which page
// is currently selected.
MenuItem item = menu
.add(Menu.NONE,
R.id.action_next,
Menu.NONE,
(mPager.getCurrentItem() == mPagerAdapter.getCount() - 1) ? R.string.action_finish
: R.string.action_next);
item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM
| MenuItem.SHOW_AS_ACTION_WITH_TEXT);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// Navigate "up" the demo structure to the launchpad activity.
// See http://developer.android.com/design/patterns/navigation.html
// for more.
NavUtils.navigateUpTo(this, new Intent(this, Login.class));
return true;
case R.id.action_previous:
// Go to the previous step in the wizard. If there is no previous
// step,
// setCurrentItem will do nothing.
mPager.setCurrentItem(mPager.getCurrentItem() - 1);
return true;
case R.id.action_next:
// Advance to the next step in the wizard. If there is no next step,
// setCurrentItem
// will do nothing.
mPager.setCurrentItem(mPager.getCurrentItem() + 1);
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A simple pager adapter that represents 5 {@link ScreenSlidePageFragment}
* objects, in sequence.
*/
public class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(android.support.v4.app.FragmentManager fm) {
super(fm);
}
@Override
public android.support.v4.app.Fragment getItem(int position) {
return ScreenSlidePageFragment.create(position);
}
@Override
public int getCount() {
return NUM_PAGES;
}
}
}
回答4:
I think i should explain the difference...
if you want to support api <11. Then you should import android.support.v4.app.FragmentPagerAdapter; and then create all Fragment by import android.support.v4.app.Fragment; and you are done.
API==11
If you don't want to support api <11. or you simply want to use simple Fragment(without support) then you should import android.support.v13.app.FragmentPagerAdapter; then getItem will need a simple Fragment.
@Override
public android.app.Fragment getItem(int position) {
return ScreenSlidePagerAdapter.create(position);
}
来源：https://stackoverflow.com/questions/14111898/the-import-android-support-v13-app-fragmentactivity-cannot-be-resolved