Java Timer幻灯片

Question

我正在构建一个Android应用程序，并试图通过使用timer类实现一个幻灯片放映。第一个图像加载正常，然后我的应用程序崩溃。你知道问题出在哪里吗？

import android.app.Service;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.IBinder;
import android.service.dreams.DreamService;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.widget.ImageView;

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

public class screenSaver extends DreamService {
    ArrayList<Bitmap> imageList = new ArrayList<Bitmap>();
    int slideCounter = 0;
    ImageView slide;
    Cursor images;
    private int counter = 0;
    public screenSaver() {

    }

    @Override
    public void onAttachedToWindow() {
        super.onAttachedToWindow();
        setInteractive(false);
        setFullscreen(true);
        setContentView(R.layout.screen_saver);
        databaseHelper dbHelper = new databaseHelper(this);
        SQLiteDatabase db = dbHelper.getReadableDatabase();
       images = db.rawQuery("SELECT " + databaseHelper.IMAGE + " FROM " + databaseHelper.TABLE_NAME + " where " + databaseHelper.LTO + " = 1", null);
        images.moveToFirst();

        while(!images.isAfterLast()) {
            imageList.add(BitmapFactory.decodeByteArray(images.getBlob(images.getColumnIndex(databaseHelper.IMAGE)), 0, images.getBlob(images.getColumnIndex(databaseHelper.IMAGE)).length ));
            images.moveToNext();
        }


        }




    @Override
    public void onDreamingStarted() {

        slide = (ImageView) findViewById(R.id.slider);
        class flipper extends TimerTask {

            @Override
            public void run() {

                slide.setImageBitmap(imageList.get(counter));
                if(counter == (imageList.size())) {
                    counter = 0;
                } else {
                    counter++;
                }

            }


        }
        Timer timer = new Timer();
        timer.scheduleAtFixedRate(new flipper(), 0, 5000);


    }
}

我已经在这个问题上挣扎了很长一段时间，所以我真的，真的很感谢大家的指导。

非常感谢！

编辑:错误

  Process: midamcorp.com.burgerkingapp, PID: 2126
                                                                           android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
                                                                               at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6556)
                                                                               at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:942)
                                                                               at android.view.ViewGroup.invalidateChild(ViewGroup.java:5081)
                                                                               at android.view.View.invalidateInternal(View.java:12713)
                                                                               at android.view.View.invalidate(View.java:12677)
                                                                               at android.view.View.invalidate(View.java:12661)
                                                                               at android.widget.ImageView.invalidateDrawable(ImageView.java:246)
                                                                               at android.graphics.drawable.Drawable.invalidateSelf(Drawable.java:385)
                                                                               at android.graphics.drawable.Drawable.setBounds(Drawable.java:165)
                                                                               at android.widget.ImageView.configureBounds(ImageView.java:1116)
                                                                               at android.widget.ImageView.updateDrawable(ImageView.java:898)
                                                                               at android.widget.ImageView.setImageDrawable(ImageView.java:472)
                                                                               at android.widget.ImageView.setImageBitmap(ImageView.java:605)
                                                                               at midamcorp.com.burgerkingapp.MainActivity$1flipper.run(MainActivity.java:48)
                                                                               at java.util.Timer$TimerImpl.run(Timer.java:284)

Answer 1

从调试消息中，错误是由线程引起的，因为它与UI不在同一线程中。

slide.setImageBitmap(imageList.get(counter));

可能的解决方案是使用Handler或runOnUIThread