【问题标题】:How to call setContentView method from a fragment class?如何从片段类调用 setContentView 方法?
【发布时间】:2016-06-17 23:43:12
【问题描述】:

我想在这个类中添加coverflow对象,但我没有找到任何解决方法。我是 Android 开发新手。

public class NoticeEvents extends Fragment {

View android;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    android = inflater.inflate(R.layout.events, container, false);

    CoverFlow coverFlow;
    coverFlow = new CoverFlow(getContext());

    coverFlow.setAdapter(new ImageAdapter(getContext()));

    ImageAdapter coverImageAdapter = new ImageAdapter(getContext());

    coverImageAdapter.createReflectedImages();

    coverFlow.setAdapter(coverImageAdapter);

    coverFlow.setSpacing(-15);
    coverFlow.setSelection(8, true);

    // i got error for this line but i need to add the coverflow object
    this.setContentView(coverFlow);

      return android;
}

public class ImageAdapter extends BaseAdapter {
    int mGalleryItemBackground;
    private Context mContext;

    private FileInputStream fis;

    private Integer[] mImageIds = {
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd,
            R.drawable.asd
    };

    private ImageView[] mImages;

    public ImageAdapter(Context c) {
        mContext = c;
        mImages = new ImageView[mImageIds.length];
    }

    public boolean createReflectedImages() {
        //The gap we want between the reflection and the original image
        final int reflectionGap = 4;


        int index = 0;
        for (int imageId : mImageIds) {
            Bitmap originalImage = BitmapFactory.decodeResource(getResources(),
                    imageId);
            int width = originalImage.getWidth();
            int height = originalImage.getHeight();


            //This will not scale but will flip on the Y axis
            Matrix matrix = new Matrix();
            matrix.preScale(1, -1);

            //Create a Bitmap with the flip matrix applied to it.
            //We only want the bottom half of the image
            Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height / 2, width, height / 2, matrix, false);


            //Create a new bitmap with same width but taller to fit reflection
            Bitmap bitmapWithReflection = Bitmap.createBitmap(width
                    , (height + height / 2), Bitmap.Config.ARGB_8888);

            //Create a new Canvas with the bitmap that's big enough for
            //the image plus gap plus reflection
            Canvas canvas = new Canvas(bitmapWithReflection);
            //Draw in the original image
            canvas.drawBitmap(originalImage, 0, 0, null);
            //Draw in the gap
            Paint deafaultPaint = new Paint();
            canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
            //Draw in the reflection
            canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

            //Create a shader that is a linear gradient that covers the reflection
            Paint paint = new Paint();
            LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0,
                    bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff,
                    Shader.TileMode.CLAMP);
            //Set the paint to use this shader (linear gradient)
            paint.setShader(shader);
            //Set the Transfer mode to be porter duff and destination in
            paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
            //Draw a rectangle using the paint with our linear gradient
            canvas.drawRect(0, height, width,
                    bitmapWithReflection.getHeight() + reflectionGap, paint);

            ImageView imageView = new ImageView(mContext);
            imageView.setImageBitmap(bitmapWithReflection);
            imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180));
            imageView.setScaleType(ImageView.ScaleType.MATRIX);
            mImages[index++] = imageView;

        }
        return true;
    }

    public int getCount() {
        return mImageIds.length;
    }

    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {

        //Use this code if you want to load from resources
        //ImageView i = new ImageView(mContext);
        //i.setImageResource(mImageIds[position]);
        //i.setLayoutParams(new CoverFlow.LayoutParams(130, 130));
        //i.setScaleType(ImageView.ScaleType.MATRIX);
        //return i;

        return mImages[position];
    }

    /**
     * Returns the size (0.0f to 1.0f) of the views
     * depending on the 'offset' to the center.
     */
    public float getScale(boolean focused, int offset) {
    /* Formula: 1 / (2 ^ offset) */
        return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
    }

}
}

这里是我的 CoverFlow 类定义 ....

public class CoverFlow extends CoverAbsSpinner implements GestureDetector.OnGestureListener {
....
}

【问题讨论】:

标签: android android-fragments setcontentview


【解决方案1】:

您没有在 Fragments 中设置内容视图。相反,你初始化你的视图并像你已经在做的那样返回它。因此,只需删除 this.setContentView(coverFlow); 即可。

【讨论】:

    【解决方案2】:

    方法setContentView仅用于活动。

    当使用片段时,您应该在 onCreateView 方法中返回 View

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    
        ViewGroup android = (ViewGroup) inflater.inflate(R.layout.events, container, false);
    
        CoverFlow coverFlow;
        coverFlow = new CoverFlow(getContext());
    
        ImageAdapter coverImageAdapter = new ImageAdapter(getContext());
    
        coverImageAdapter.createReflectedImages();
    
        coverFlow.setAdapter(coverImageAdapter);
    
        coverFlow.setSpacing(-15);
        coverFlow.setSelection(8, true);
    
    
        android.addView(coverFlow);
        return android;
    }
    

    【讨论】:

    • 我编辑了答案,现在试试。如果它不起作用,请发布您的events.xml
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