【Android】神奇的android:clipChildren屬性

聲明

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正文

截圖

   

 

代碼

java

public class HoDragActivity extends Activity {

    private LinearLayout main;

    private GestureDetector mGestureDetector;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_cc);

        main = (LinearLayout) findViewById(R.id.main);

        bindDrapListener(R.id.myimage1);
        bindDrapListener(R.id.myimage2);
        bindDrapListener(R.id.myimage3);
        bindDrapListener(R.id.myimage4);
        bindDrapListener(R.id.myimage5);
        bindDrapListener(R.id.myimage6);
        bindDrapListener(R.id.myimage7);
        bindDrapListener(R.id.myimage8);
        bindDrapListener(R.id.myimage9);
        bindDrapListener(R.id.myimage10);
        bindDrapListener(R.id.myimage11);
        bindDrapListener(R.id.myimage12);

        mGestureDetector = new GestureDetector(this, new DrapGestureListener());
    }

    private View mDrapView;

    private void bindDrapListener(int id) {
        View v = findViewById(id);
        v.setOnTouchListener(mOnTouchListener);
        v.setOnDragListener(mOnDragListener);
    }

    private OnTouchListener mOnTouchListener = new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            mDrapView = v;

            if (mGestureDetector.onTouchEvent(event))
                return true;

            switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_UP:

                break;
            }

            return false;
        }
    };

    private OnDragListener mOnDragListener = new OnDragListener() {

        @Override
        public boolean onDrag(View v, DragEvent event) {
            switch (event.getAction()) {
            case DragEvent.ACTION_DRAG_STARTED:
                // Do nothing
                break;
            case DragEvent.ACTION_DRAG_ENTERED:
                v.setAlpha(0.5F);
                break;
            case DragEvent.ACTION_DRAG_EXITED:
                v.setAlpha(1F);
                break;
            case DragEvent.ACTION_DROP:
                View view = (View) event.getLocalState();
                for (int i = 0, j = main.getChildCount(); i < j; i++) {
                    if (main.getChildAt(i) == v) {
                        // 當前位置
                        main.removeView(view);
                        main.addView(view, i);
                        break;
                    }
                }
                break;
            case DragEvent.ACTION_DRAG_ENDED:
                v.setAlpha(1F);
            default:
                break;
            }
            return true;
        }
    };

    private class DrapGestureListener extends SimpleOnGestureListener {
        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            return super.onSingleTapConfirmed(e);
        }

        @Override
        public void onLongPress(MotionEvent e) {
            super.onLongPress(e);
            ClipData data = ClipData.newPlainText("", "");
            MyDragShadowBuilder shadowBuilder = new MyDragShadowBuilder(
                    mDrapView);
            mDrapView.startDrag(data, shadowBuilder, mDrapView, 0);
        }

        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }
    }

    private class MyDragShadowBuilder extends View.DragShadowBuilder {

        private final WeakReference<View> mView;

        public MyDragShadowBuilder(View view) {
            super(view);
            mView = new WeakReference<View>(view);
        }

        @Override
        public void onDrawShadow(Canvas canvas) {
            canvas.scale(1.5F, 1.5F);
            super.onDrawShadow(canvas);
        }

        @Override
        public void onProvideShadowMetrics(Point shadowSize,
                Point shadowTouchPoint) {
            // super.onProvideShadowMetrics(shadowSize, shadowTouchPoint);

            final View view = mView.get();
            if (view != null) {
                shadowSize.set((int) (view.getWidth() * 1.5F),
                        (int) (view.getHeight() * 1.5F));
                shadowTouchPoint.set(shadowSize.x / 2, shadowSize.y / 2);
            } else {
                // Log.e(View.VIEW_LOG_TAG,
                // "Asked for drag thumb metrics but no view");
            }
        }
    }
}

代碼說明

1、 MyDragShadowBuilder主要用於縮放拖拽的ImageView，這裏放大了1.5倍，而又不至於影響原控件，這裏是放大兩倍

2、這裏是通過長按來喚起拖拽操作，所以監聽了onLongPress

3、注意拖拽onDragListener是Android 3.0才新增的API

 

文章

Android Drag and Drop - Tutorial 

Android開發者指南-用戶界面-拖放-Drag and Drop 

下載

 VogellaDraganddrop.zip

 

結束

歡迎交流！想做成拖動插入時自動兩邊擠開的效果，沒弄出來，出來是抖動的效果。