自定义控件实现微博图片九宫格效果

1：自定义GridView

public class NineGridlayout extends ViewGroup {    private NineGridAdapter adapter;    private OnItemClickListerner onItemClickListerner;    // 行间距    private int lineSpace;    //列间距    private int gap;    private final int DEFAULT_WIDTH = 140;    private int columns;//    private int rows;//    private int totalWidth;    private Context context;    int singleWidth = 0, singleHeight = 0;    private int defaultWidth, defaultHeight;    private int oldCount;    public NineGridlayout(Context context) {        this(context, null);    }    public NineGridlayout(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public NineGridlayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        this.context = context;        gap = dip2px(context, 10);        lineSpace = dip2px(context,10);        defaultWidth = defaultHeight = dip2px(context, DEFAULT_WIDTH);    }    public void setDefaultWidth(int defaultWidth) {        this.defaultWidth = defaultWidth;    }    public void setDefaultHeight(int defaultHeight) {        this.defaultHeight = defaultHeight;    }    public void setAdapter(NineGridAdapter adapter) {        this.adapter = adapter;        if (adapter == null) {            return;        }        //初始化布局形状        generateChildrenLayout(adapter.getCount());        //这里做一个重用view的处理//        if (oldCount == 0) {        removeAllViews();        for (int i = 0; i < adapter.getCount(); i++) {            View itemView = adapter.getView(i, null);            addView(itemView, generateDefaultLayoutParams());        }//        }         /*else {            //以前添加过view            int newViewCount = adapter.getCount();            if (oldCount > newViewCount) {                removeViews(newViewCount - 1, oldCount - newViewCount);                for (int i = 0; i < newViewCount - 1; i++) {                    adapter.getView(i, getChildAt(i));                }            } else if (oldCount < newViewCount) {                for (int i = 0; i < newViewCount - oldCount; i++) {                    View itemView = adapter.getView(i, null);                    addView(itemView, generateDefaultLayoutParams());                }            }        }*/        oldCount = adapter.getCount();        requestLayout();    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        int widthMode = MeasureSpec.getMode(widthMeasureSpec);        int heightMode = MeasureSpec.getMode(heightMeasureSpec);        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);        totalWidth = sizeWidth - getPaddingLeft() - getPaddingRight();        if (adapter != null && adapter.getCount() > 0) {            int measureWidth, measureHeight;            int childrenCount = adapter.getCount();            if (childrenCount == 1) {                singleWidth = defaultWidth;                singleHeight = defaultHeight;            } else {                singleWidth = (totalWidth - gap * (3 - 1)) / 3;                singleHeight = singleWidth;            }            measureChildren(MeasureSpec.makeMeasureSpec(singleWidth, MeasureSpec.EXACTLY),                    MeasureSpec.makeMeasureSpec(singleHeight, MeasureSpec.EXACTLY));            measureWidth = singleWidth * columns + gap * (columns - 1);            measureHeight = singleHeight * rows + lineSpace * (rows - 1);            setMeasuredDimension(sizeWidth, measureHeight);        }    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        layoutChildrenView();    }    private void layoutChildrenView() {        if (adapter == null || adapter.getCount() == 0) {            return;        }        int childrenCount = adapter.getCount();        for (int i = 0; i < childrenCount; i++) {            int[] position = findPosition(i);            int left = (singleWidth + gap) * position[1] + getPaddingLeft();            int top = (singleHeight + lineSpace) * position[0] + getPaddingTop();            int right = left + singleWidth;            int bottom = top + singleHeight;            ImageView childrenView = (ImageView) getChildAt(i);            if (childrenCount == 1) {                //只有一张图片                childrenView.setScaleType(ImageView.ScaleType.FIT_CENTER);            } else {                childrenView.setScaleType(ImageView.ScaleType.CENTER_CROP);            }            final int itemPosition = i;            childrenView.setOnClickListener(new OnClickListener() {                @Override                public void onClick(View v) {                    if (onItemClickListerner != null) {                        onItemClickListerner.onItemClick(v, itemPosition);                    }                }            });            childrenView.layout(left, top, right, bottom);        }    }    private int[] findPosition(int childNum) {        int[] position = new int[2];        for (int i = 0; i < rows; i++) {            for (int j = 0; j < columns; j++) {                if ((i * columns + j) == childNum) {                    position[0] = i;//行                    position[1] = j;//列                    break;                }            }        }        return position;    }    public int getGap() {        return gap;    }    public void setGap(int gap) {        this.gap = gap;    }    /**     * 根据图片个数确定行列数量     * 对应关系如下     * numrowcolumn     * 1   11     * 2   12     * 3   13     * 4   22     * 5   23     * 6   23     * 7   33     * 8   33     * 9   33     *     * @param length     */    private void generateChildrenLayout(int length) {        if (length <= 3) {            rows = 1;            columns = length;        } else if (length <= 6) {            rows = 2;            columns = 3;            if (length == 4) {                columns = 2;            }        } else {            rows = 3;            columns = 3;        }    }    /**     * dp to px     */    public static int dip2px(Context context, float dpValue) {        final float scale = context.getResources().getDisplayMetrics().density;        return (int) (dpValue * scale + 0.5f);    }    public void setOnItemClickListerner(OnItemClickListerner onItemClickListerner) {        this.onItemClickListerner = onItemClickListerner;    }    public interface OnItemClickListerner {        public void onItemClick(View view, int position);    }}

2：自定义Adapter

public abstract class NineGridAdapter {    protected Context context;    protected List list;    public NineGridAdapter(Context context, List list) {        this.context = context;        this.list = list;    }    public abstract int getCount();    public abstract String getUrl(int positopn);    public abstract Object getItem(int position);    public abstract long getItemId(int position);    public abstract View getView(int i, View view);}

3：MainActivity中正常调用，和GridView一样使用。xml布局中的控件写自定义的控件然后就可以使用了。

public class SinaActivity extends BaseActivity{    private String imageUrl = "http://pic1.nipic.com/2008-09-08/200898163242920_2.jpg";    private List<String> list = new ArrayList<String>();    private ImageLoader imageLoader;    private Adapter adapter;    private NineGridlayout mGV;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_sina);        mGV = (NineGridlayout) findViewById(R.id.iv_ngrid_layout);        imageLoader = ImageLoader.getInstance();        for (int i = 0;i<4;i++){            list.add(imageUrl);        }        if (adapter == null){            adapter = new Adapter(this,list);            mGV.setAdapter(adapter);        }        mGV.setOnItemClickListerner(new NineGridlayout.OnItemClickListerner() {            @Override            public void onItemClick(View view, int position) {                Toast.makeText(getApplicationContext(), String.valueOf(position),Toast.LENGTH_LONG).show();            }        });    }     private class Adapter extends NineGridAdapter {         public Adapter(Context context, List list){             super(context,list);         }        @Override        public int getCount() {            return list == null?0:list.size();        }        @Override        public String getUrl(int positon) {            return getItem(positon) == null ? null : getItem(positon).toString();        }        @Override        public Object getItem(int position) {            return (list == null) ? null : list.get(position);        }        @Override        public long getItemId(int position) {            return position;        }        @Override        public View getView(int i, View view) {//            ImageView imageView = new ImageView(getApplicationContext());            ViewGroup.LayoutParams lp = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,                    ViewGroup.LayoutParams.WRAP_CONTENT);            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);            imageView.setBackgroundColor(Color.parseColor("#f5f5f5"));            imageView.setLayoutParams(lp);            imageLoader.displayImage(getUrl(i),imageView);            return imageView;        }    }    @Override    public void onClick(View v) {    }}