Question

我正在尝试创建一个显示一些片段的活动。我在这里遵循这个例子：http://developer.android.com/training/animation/screen-slide.html，但似乎有一些代码/不一致的缺失。我已经缩小了许多问题，但我只是坚持了一个部分，尽管对于知道这种方法的人来说似乎很简单。

private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm) {
    super(fm); // error on fm
}

错误在fm上强调super(fm);： FragmentStatePagerAdapter中的FragmentStatePagerAdapter（android.support.v4.app.FragmentManager）无法应用于（android.app.FragmentManager）“

@Override
public Fragment getItem(int position) { // error on Fragment
    return ScreenSlidePageFragment.create(position);
}

错误在Fragment上强调public Fragment getItem(int position) {：'com.example.Application.ScreenSlideActivity.ScreenSlidePagerAdapter'中的'getItem（int）'与'android中的'getItem（int）'冲突。 support.v4.app.FragmentStatePagerAdapter“;尝试使用不兼容的返回类型

ScreenSlideActivity.java：

package com.example.dgzl.corvegas;

import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Intent;
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 ScreenSlideActivity extends android.support.v4.app.FragmentActivity {

    /* The number of pages (wizard steps) to show in this demo.*/
    private static final int NUM_PAGES = 3;

    /* 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_prev).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)
                        ? "action_finish"
                        : "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;
        }
    }
}

ScreenSlidePageFragment.java“

package com.example.Application
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class ScreenSlidePageFragment extends Fragment {

public static final String ARG_PAGE = "page";

private int mPageNumber;

public static ScreenSlidePageFragment create(int pageNumber) {
    ScreenSlidePageFragment fragment = new ScreenSlidePageFragment();
    Bundle args = new Bundle();
    args.putInt(ARG_PAGE, pageNumber);
    fragment.setArguments(args);
    return fragment;
}

public ScreenSlidePageFragment() {
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mPageNumber = getArguments().getInt(ARG_PAGE);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout containing a title and body text.
    ViewGroup rootView = (ViewGroup) inflater
            .inflate(R.layout.fragment_today, container, false);

    // Set the title view to show the page number.
    ((TextView) rootView.findViewById(android.R.id.text1)).setText(
            getString(R.string.title_template_step, mPageNumber + 1));

    return rootView;
}

/**
 * Returns the page number represented by this fragment object.
 */
public int getPageNumber() {
    return mPageNumber;
}
}

Answer 1

您必须从支持库导入Fragment和FragmentManager类，请在ScreenSlideActivity类中更改前两行导入

import  android.support.v4.app.FragmentManager
import android.support.v4.app.Fragment

android.support.v4.app和android.app

1 个答案: