在片段内的 ViewFlipper 中自动翻转图像

Question

我正在尝试使用 ViewFlipper 自动更改片段内的图像。我的活动代码是：

package com.example.scientia;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.Toast;
import android.widget.ViewFlipper;

public class HomeActivity extends Activity implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    private NavigationDrawerFragment mNavigationDrawerFragment; //manages behaviors of navigation drawer

    private CharSequence mTitle; //stores title of last screen

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

        mNavigationDrawerFragment = (NavigationDrawerFragment) getFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout));
    }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
        // update the main content by replacing fragments
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction ft = fragmentManager.beginTransaction();
        fragmentManager.beginTransaction().replace(R.id.fragment1, PlaceholderFragment.newInstance(position + 1))
                .commit();
        if(position == 0)
        {
            Fragment f1 = new HomeFragment();
            ft.replace(R.id.fragment1, f1);
            ft.commit();
        }
        if(position == 1)
        {
            Fragment f1 = new IqQuiz();
            ft.replace(R.id.fragment1, f1);
            ft.commit();
        }
        if(position == 2)
        {
            Fragment f1 = new LogicalQuiz();
            ft.replace(R.id.fragment1, f1);
            ft.commit();
        }
        if(position == 3)
        {
            Fragment f1 = new AptitudeQuiz();
            ft.replace(R.id.fragment1, f1);
            ft.commit();
        }
        if(position == 4)
        {
            Fragment f1 = new VerbalQuiz();
            ft.replace(R.id.fragment1, f1);
            ft.commit();
        }
    }

    public void onSectionAttached(int number) {
        switch (number) {
        case 1:
            mTitle = getString(R.string.title_section1);
            break;
        case 2:
            mTitle = getString(R.string.title_section2);
            break;
        case 3:
            mTitle = getString(R.string.title_section3);
            break;
        case 4:
            mTitle = getString(R.string.title_section4);
            break;
        case 5:
            mTitle = getString(R.string.title_section5);
            break;
        }
    }

    public void restoreActionBar() {
        ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(mTitle);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        if (!mNavigationDrawerFragment.isDrawerOpen()) {
            getMenuInflater().inflate(R.menu.home, menu);
            restoreActionBar();
            return true;
        }
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) { //handles action bar item clicks
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public static class PlaceholderFragment extends Fragment { //placeholder containes a simple view

        private static final String ARG_SECTION_NUMBER = "section_number";

        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment(); //returns new fragment for the section number
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_home, container, false);
            ViewFlipper viewflipper = (ViewFlipper) rootView.findViewById(R.id.view_flipper);
            viewflipper.setAutoStart(true);
            viewflipper.setFlipInterval(300);
            viewflipper.startFlipping();
            Toast.makeText(getActivity(), "Flipping", 300);
            return rootView;
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            ((HomeActivity) activity).onSectionAttached(getArguments().getInt(ARG_SECTION_NUMBER));
        }
    }

}

相关的片段XML文件编码为：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.scientia.HomeActivity$PlaceholderFragment" >


    <ViewFlipper
        android:id="@+id/view_flipper"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">

            <ImageView
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_gravity="center"
                android:adjustViewBounds="true"
                android:scaleType="centerCrop"
                android:src="@drawable/school" />

            <TextView
                style="@style/ImageTitle"
                android:text="School" />
        </RelativeLayout>

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">

            <ImageView
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_gravity="center"
                android:adjustViewBounds="true"
                android:scaleType="centerCrop"
                android:src="@drawable/retina_wood" />

            <TextView
                style="@style/ImageTitle"
                android:text="Retina Woods" />
        </RelativeLayout>

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">

            <ImageView
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_gravity="center"
                android:adjustViewBounds="true"
                android:scaleType="centerCrop"
                android:src="@drawable/skulls" />

            <TextView
                style="@style/ImageTitle"
                android:text="Skulls" />
        </RelativeLayout>
    </ViewFlipper>

</RelativeLayout>

没有编译错误或应用程序崩溃，但图像不会自动翻转。请帮忙！

Answer 1

我不明白为什么你的 ViewFlipper 中有所有这些 RelativeLayout。尝试从 ViewFlipper 中删除所有这些 RelativeLayout，并在 xml 文件中为 ViewFlipper 设置属性android:flipInterval="3000"android:autoStart="true"。如果您还需要组织您的 TextViews 和 ImageViews，只需使用 android:layout_below="@+id/XXXXXX" 将一个放在另一个下方。