使所选项目更大gridview android

Question

我制作电视应用程序演示。我想让选定的项目更大。 来自movies.xml的数据 我的代码。

public class MainActivity extends Activity {
    private XmlPullParser xpp;
    private InputStream input;
    private List<Movie> movieList = new ArrayList<Movie>();

    private MyAdapter adapter;
    private GridView gridview;

    private static final String MOVIE = "movie";
    private static final String ID = "id";
    private static final String TITLE = "title";
    private static final String BACKGROUND = "background";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gridview = (GridView) findViewById(R.id.gridview);
        movieList = createMovies();
        adapter = new MyAdapter(this, movieList);
        gridview.setAdapter(adapter);
        gridview.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> parent, View view,
                    int position, long id) {
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });
        String str = "123456";
    }

    /*
     * 从xml中获取movies的信息
     * */
    public List<Movie> createMovies() {
        List<Movie> resultList = new ArrayList<Movie>();
        xpp = Xml.newPullParser();
        Movie item = null;
        try {
            input = getResources().getAssets().open("movies.xml");
            xpp.setInput(input,"utf-8");
            int type = xpp.getEventType();
            while(type!=XmlPullParser.END_DOCUMENT){
                switch(type){
                case XmlPullParser.START_TAG:
                    String name = xpp.getName();
                    if(name.equalsIgnoreCase(MOVIE)){
                        item = new Movie();
                    }else if(item!=null){
                        if(name.equalsIgnoreCase(ID)){
                            item.setId(Integer.parseInt(xpp.nextText()));
                        }else if(name.equalsIgnoreCase(TITLE)){
                            item.setTitle(xpp.nextText());
                        }
                        else if(name.equalsIgnoreCase(BACKGROUND)){
                            item.setBackground(xpp.nextText());
                        }
                    }
                    break;
                case XmlPullParser.END_TAG:
                    if(xpp.getName().equalsIgnoreCase(MOVIE) && item!=null){
                        resultList.add(item);
                        item = null;
                    }
                default:
                    break;
                }
                type = xpp.next();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return resultList;
    }

}

我的自定义适配器。我做了一个测试，使第二个项目更大ObjectAnimator。但它不起作用。

public class MyAdapter extends BaseAdapter {
    private Context mContext;
    private LayoutInflater mInflater;
    private List<Movie> movieList;

    private ObjectAnimator mZoomInAnimation;
    private ObjectAnimator mZoomOutAnimation;

    public MyAdapter(Context context,List<Movie> list){
        mContext = context;
        mInflater = LayoutInflater.from(mContext);
        movieList = list;
        initAnimation();
    }

    @Override
    public int getCount() {
        return movieList.size();
    }

    @Override
    public Object getItem(int position) {
        return movieList.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        if(null == convertView){
            convertView = mInflater.inflate(R.layout.item_grid_view, null);
            holder = new ViewHolder();

            holder.view = convertView.findViewById(R.id.border);
            LayoutParams params = (LayoutParams) holder.view.getLayoutParams();
            params.height = 300 + 15;
            params.width = 250 + 15;

            holder.background = (ImageView) convertView.findViewById(R.id.background);
            LayoutParams backLayoutParams = (LayoutParams) holder.background.getLayoutParams();
            backLayoutParams.height = 300;
            backLayoutParams.width = 250;

            holder.title = (TextView) convertView.findViewById(R.id.title);
            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }
        holder.title.setText(movieList.get(position).getTitle());

//      int i = mContext.getResources().getIdentifier("drawable/photography1", null, mContext.getPackageName());
//      holder.background.setImageResource(i);

        AssetManager assetManager = mContext.getAssets();
        InputStream istr;
        String url = movieList.get(position).getBackground();
        String str = url.substring(9);
        try { 
            istr = assetManager.open(str);
            Bitmap bitmap = BitmapFactory.decodeStream(istr);
            holder.background.setBackgroundDrawable(new BitmapDrawable(bitmap));
            istr.close();
        } catch (IOException e) {
            e.printStackTrace();
        } 
        //mContext.getResources().getDrawable(R.drawable.list_detail_item_border).getConstantState()
//        Boolean is = holder.background.getDrawable().getCurrent().getConstantState().equals(null)?true:false;
        if(position == 1){   //如果view的图片是list_detail_item_border则一个动画
            if(mZoomInAnimation!=null){
                mZoomOutAnimation.cancel();
                mZoomInAnimation.start();
            }
        }
        else{ // 如果不是则另外一个动画
            if(mZoomOutAnimation!=null){
                mZoomInAnimation.cancel();
                mZoomOutAnimation.start();
            }
        }
        return convertView;
    }

    public class ViewHolder{
        public View view;
        public ImageView background;
        public TextView title;
    }


    public void initAnimation() {

        float endVal = 2.2f;
        PropertyValuesHolder inScaleX = PropertyValuesHolder.ofFloat("scaleX", 1.0f, endVal);
        PropertyValuesHolder inScaleY = PropertyValuesHolder.ofFloat("scaleY", 1.0f, endVal);

        mZoomInAnimation = new ObjectAnimator();
        mZoomInAnimation.setTarget(this);
        mZoomInAnimation.setValues(inScaleX, inScaleY);
        mZoomInAnimation.setDuration(200);

        PropertyValuesHolder outScaleX = PropertyValuesHolder.ofFloat("scaleX", endVal, 1.0f);
        PropertyValuesHolder outScaleY = PropertyValuesHolder.ofFloat("scaleY", endVal, 1.0f);

        mZoomOutAnimation = new ObjectAnimator();
        mZoomOutAnimation.setTarget(this);
        mZoomOutAnimation.setValues(outScaleX, outScaleY);
        mZoomOutAnimation.setDuration(200);
    }