Question

我已经使用gridlist创建了android应用程序，并且可以滑动图片，如图库或小书，有10张图片

网格列表和图片视图已成功打开，我可以启动该应用程序。

功能也很好但是当我想从网格列表中滑动下一个图像时，我的应用关闭并显示应用已停止并再次打开应用的消息。

请查看我的代码并指导我如何解决此问题。这是我的代码： -

public class MainActivity extends ActionBarActivity {

    private GridView gv;
    private Animator mCurrentAnimator;
    private int mShortAnimationDuration;
    private int j = 0;

    private GestureDetector detector;
    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;

    private int thumb[] = { R.drawable.img_android, R.drawable.img_chrome,
            R.drawable.img_facebook, R.drawable.img_firefox,
            R.drawable.img_gmail, R.drawable.img_google_plus,
            R.drawable.img_java, R.drawable.img_linux, R.drawable.img_skype,
            R.drawable.img_twitter, R.drawable.img_windows,
            R.drawable.img_wordpress };

    private ImageView expandedImageView;

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

        detector = new GestureDetector(this, new SwipeGestureDetector());

        gv = (GridView) findViewById(R.id.grid_view);
        gv.setAdapter(new ImageAdapter(this));
        gv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View v, int pos,
                    long id) {
                j = pos;
                zoomImageFromThumb(v, thumb[pos]);
            }
        });

        mShortAnimationDuration = getResources().getInteger(android.R.integer.config_shortAnimTime);
    }

    class ImageAdapter extends BaseAdapter{

        private LayoutInflater layoutInflater;

        public ImageAdapter(MainActivity activity) {
            layoutInflater = (LayoutInflater) activity
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        @Override
        public int getCount() {
            return thumb.length;
        }

        @Override
        public Object getItem(int pos) {
            return pos;
        }

        @Override
        public long getItemId(int pos) {
            return pos;
        }

        @Override
        public View getView(int pos, View convertView, ViewGroup parent) {

            View listItem = convertView;
            int p = pos;

            if(listItem == null) {
                listItem = layoutInflater.inflate(R.layout.single_grid_item, null);
            }

            ImageView iv = (ImageView) listItem.findViewById(R.id.thumb);

            iv.setBackgroundResource(thumb[p]);

            return listItem;
        }
    }

    private void zoomImageFromThumb(final View thumbView, int imageResId) {

        if(mCurrentAnimator != null) {
            mCurrentAnimator.cancel();
        }

        expandedImageView = (ImageView) findViewById(R.id.expanded_image);

        expandedImageView.setOnTouchListener(new View.OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(detector.onTouchEvent(event)){
                    return true;
                } else {
                    return false;
                }
            }
        });

        expandedImageView.setImageResource(imageResId);

        final Rect startBounds = new Rect();
        final Rect finalBounds = new Rect();
        final Point globalOffset = new Point();

        thumbView.getGlobalVisibleRect(startBounds);
        findViewById(R.id.container).getGlobalVisibleRect(finalBounds, globalOffset);

        startBounds.offset(-globalOffset.x, -globalOffset.y);
        finalBounds.offset(-globalOffset.x, -globalOffset.y);

        float startScale;

        if ((float) finalBounds.width() / finalBounds.height() > (float) startBounds
                .width() / startBounds.height()) {

            startScale = (float) startBounds.height() / finalBounds.height();
            float startWidth = startScale * finalBounds.width();
            float deltaWidth = (startWidth - startBounds.width()) / 2;
            startBounds.left -= deltaWidth;
            startBounds.right += deltaWidth;

        } else {

            startScale = (float) startBounds.width() / finalBounds.width();
            float startHeight = startScale * finalBounds.height();
            float deltaHeight = (startHeight = startBounds.height()) / 2;
            startBounds.top -= deltaHeight;
            startBounds.bottom += deltaHeight;
        }

        thumbView.setAlpha(0f);
        expandedImageView.setVisibility(View.VISIBLE);

        expandedImageView.setPivotX(0f);
        expandedImageView.setPivotY(0f);

        AnimatorSet set = new AnimatorSet();

        set.play(ObjectAnimator.ofFloat(expandedImageView, View.X, startBounds.left, finalBounds.left))
        .with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top, finalBounds.top))
        .with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_X, startScale, 1f))
        .with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_Y, startScale, 1f));

        set.setDuration(mShortAnimationDuration);
        set.setInterpolator(new DecelerateInterpolator());
        set.addListener(new AnimatorListenerAdapter() {

            @Override
            public void onAnimationEnd(Animator animation) {
                mCurrentAnimator = null;
            }

            @Override
            public void onAnimationCancel(Animator animation) {
                mCurrentAnimator = null;
            }
        });
        set.start();
        mCurrentAnimator = set;

        final float startScaleFinal = startScale;
        expandedImageView.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                if(mCurrentAnimator != null) {
                    mCurrentAnimator.cancel();
                }

                AnimatorSet set = new AnimatorSet();

                set.play(ObjectAnimator.ofFloat(expandedImageView, View.X, startBounds.left))
                .with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top))
                .with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_X, startScaleFinal))
                .with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_Y, startScaleFinal));

                set.setDuration(mShortAnimationDuration);
                set.setInterpolator(new DecelerateInterpolator());
                set.addListener(new AnimatorListenerAdapter() {

                    @Override
                    public void onAnimationEnd(Animator animation) {
                        thumbView.setAlpha(1f);
                        expandedImageView.setVisibility(View.GONE);
                        mCurrentAnimator = null;
                    }

                    @Override
                    public void onAnimationCancel(Animator animation) {
                        thumbView.setAlpha(1f);
                        expandedImageView.setVisibility(View.GONE);
                        mCurrentAnimator = null;
                    }
                });
                set.start();
                mCurrentAnimator = set;
            }
        });
    }

    private class SwipeGestureDetector extends GestureDetector.SimpleOnGestureListener{
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                float velocityY) {

            try {

                if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY){

                    if(thumb.length > j) {
                        j++;

                        if(j < thumb.length) {
                            expandedImageView.setImageResource(thumb[j]);
                            return true;
                        } else {
                            j = 0;
                            expandedImageView.setImageResource(thumb[j]);
                            return true;
                        }
                    }
                } else if(e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {

                    if(j > 0) {
                        j--;
                        expandedImageView.setImageResource(thumb[j]);
                        return true;
                    } else {
                        j = thumb.length - 1;
                        expandedImageView.setImageResource(thumb[j]);
                        return true;
                    }
                }
            } catch(Exception e) {
                e.printStackTrace();
            }
            return false;
        }
    }
}

Answer 1

您可以使用View Pager For Swipeable Views / fragment。

将此代码写入布局文件activity_main.xml。

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </android.support.v4.view.ViewPager>

接下来，在您的onCreate() Activity方法中，您将实例化您的自定义PagerAdapter实现并将其绑定到您的ViewPager对象。

 CustomPagerAdapter mCustomPagerAdapter = new CustomPagerAdapter(this);

   ViewPager mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mCustomPagerAdapter);

之后创建一个布局文件（pager_item.xml），该文件一次会在ViewPager上曝光，并且会包含ImageView类似这样的内容。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/imageView" />
</LinearLayout>

现在创建一个新类CustomPagerAdapter.java并编写自定义寻呼机适配器实现，它将在ViewPager中填充内容页面。

public class CustomPagerAdapter extends PagerAdapter {

   private int mResources[] = { R.drawable.img_android, R.drawable.img_chrome,
        R.drawable.img_facebook, R.drawable.img_firefox,
        R.drawable.img_gmail, R.drawable.img_google_plus,
        R.drawable.img_java, R.drawable.img_linux, R.drawable.img_skype,
        R.drawable.img_twitter, R.drawable.img_windows,
        R.drawable.img_wordpress };


    Context mContext;
    LayoutInflater mLayoutInflater;

    public CustomPagerAdapter(Context context) {
        mContext = context;
        mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return mResources.length;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((LinearLayout) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        View itemView = mLayoutInflater.inflate(R.layout.pager_item, container, false);

        ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);
        imageView.setImageResource(mResources[position]);

        container.addView(itemView);

        return itemView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((LinearLayout) object);
    }
}

Answer 2

好的，这是另一个问题的另一个答案

您必须使用GridView（已完成）创建两个活动，使用ViewPager创建另一个活动（您可以在我的第一个回答的帮助下创建）。

现在，您希望点击ViewPager点击GridView，了解如何执行此操作： -

 gv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View v, int pos,
                    long id) {
                Intent intent = new Intent(MainActivity.this,ViewPagerActivity.class);
                intent.putExtra("position",pos);
                startActivity(intent);
            }
        });

现在是ViewPagerActivity.java： -

import android.support.v7.app.AppCompatActivity;
public class ViewPagerActivity extends AppCompatActivity{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         CustomPagerAdapter mCustomPagerAdapter = new CustomPagerAdapter(this);

         Intent mIntent = getIntent();
         int position= mIntent.getIntExtra("position", 0);

         ViewPager mViewPager = (ViewPager) findViewById(R.id.pager);
         mViewPager.setAdapter(mCustomPagerAdapter);
         mViewPager.setCurrentItem(position);

    }
}

类SwipeGestureDetector无法在我的应用程序中工作

2 个答案: