在xml文件中为线性布局设置左侧的阴影效果

Question

我想在xml中的一个布局上设置阴影效果。当我滑动First Activity时，我想在它上面设置阴影效果。可以有人帮我设置阴影效果。这是我的完整代码。< / p>

public class MainLayout extends LinearLayout
{
     private static final int SLIDING_DURATION = 500;
    private static final int QUERY_INTERVAL = 16;
    int mainLayoutWidth;
    private View menu;
    private View content;
    private static int menuRightMargin = 15;

    private enum MenuState
    {
        HIDING, HIDDEN, SHOWING, SHOWN,
    };

    private int contentXOffset;
    private MenuState currentMenuState = MenuState.HIDDEN;
    private Scroller menuScroller = new Scroller(this.getContext(),
            new EaseInInterpolator());
    private Runnable menuRunnable = new MenuRunnable();
    private Handler menuHandler = new Handler();
    int prevX = 0;
    boolean isDragging = false;
    int lastDiffX = 0;

    public MainLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MainLayout(Context context) {
        super(context);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        mainLayoutWidth = MeasureSpec.getSize(widthMeasureSpec);
        menuRightMargin = mainLayoutWidth * 10 / 100;
    }

    @Override
    protected void onAttachedToWindow()
    {
        super.onAttachedToWindow();

        menu = this.getChildAt(0);
        content = this.getChildAt(1);
        content.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return MainLayout.this.onContentTouch(v, event);
            }
        });
        menu.setVisibility(View.GONE);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right,
            int bottom) {
        if (changed)
        {
            LayoutParams contentLayoutParams = (LayoutParams) content.getLayoutParams();
            contentLayoutParams.height = this.getHeight();
            contentLayoutParams.width = this.getWidth();
            LayoutParams menuLayoutParams = (LayoutParams) menu.getLayoutParams();
            menuLayoutParams.height = this.getHeight();
            menuLayoutParams.width = this.getWidth() - menuRightMargin;
        }

        menu.layout(left, top, right - menuRightMargin, bottom);
        content.layout(left + contentXOffset, top, right + contentXOffset,
                bottom);

    }

    public void toggleMenu()
    {

        if (currentMenuState == MenuState.HIDING
                || currentMenuState == MenuState.SHOWING)
            return;

        switch (currentMenuState)
        {
        case HIDDEN:
            currentMenuState = MenuState.SHOWING;
            menu.setVisibility(View.VISIBLE);

            menuScroller.startScroll(0, 0, menu.getLayoutParams().width, 0,
                    SLIDING_DURATION);
            break;
        case SHOWN:
            currentMenuState = MenuState.HIDING;
            menuScroller.startScroll(contentXOffset, 0, -contentXOffset, 0,
                    SLIDING_DURATION);
            break;
        default:
            break;
        }
        menuHandler.postDelayed(menuRunnable, QUERY_INTERVAL);
        this.invalidate();
    }

    protected class MenuRunnable implements Runnable
    {
        @Override
        public void run() {
            boolean isScrolling = menuScroller.computeScrollOffset();
            adjustContentPosition(isScrolling);
        }
    }

    private void adjustContentPosition(boolean isScrolling)
    {
        int scrollerXOffset = menuScroller.getCurrX();

        content.offsetLeftAndRight(scrollerXOffset - contentXOffset);

        contentXOffset = scrollerXOffset;
        this.invalidate();
        if (isScrolling)
            menuHandler.postDelayed(menuRunnable, QUERY_INTERVAL);
        else
            this.onMenuSlidingComplete();
    }

    private void onMenuSlidingComplete()
    {
        switch (currentMenuState)
        {
        case SHOWING:
            currentMenuState = MenuState.SHOWN;
            break;
        case HIDING:
            currentMenuState = MenuState.HIDDEN;
            menu.setVisibility(View.GONE);
            break;
        default:
            return;
        }
    }

    protected class EaseInInterpolator implements Interpolator
    {
        @Override
        public float getInterpolation(float t) {
            return (float) Math.pow(t - 1, 5) + 1;
        }

    }

    public boolean isMenuShown() {
        return currentMenuState == MenuState.SHOWN;
    }

    public boolean onContentTouch(View v, MotionEvent event) {
        if (currentMenuState == MenuState.HIDING
                || currentMenuState == MenuState.SHOWING)
            return false;
        int curX = (int) event.getRawX();
        int diffX = 0;

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:

            prevX = curX;
            return true;

        case MotionEvent.ACTION_MOVE:
            if (!isDragging) {
                isDragging = true;
                menu.setVisibility(View.VISIBLE);
            }
            diffX = curX - prevX;
            if (contentXOffset + diffX <= 0) {
                diffX = -contentXOffset;
            } else if (contentXOffset + diffX > mainLayoutWidth
                    - menuRightMargin) {
                diffX = mainLayoutWidth - menuRightMargin - contentXOffset;
            }
            content.offsetLeftAndRight(diffX);
            contentXOffset += diffX;
            this.invalidate();

            prevX = curX;
            lastDiffX = diffX;
            return true;

        case MotionEvent.ACTION_UP:
            Log.d("MainLayout.", "java onContentTouch() Up lastDiffX " + lastDiffX);

            if (lastDiffX > 0) {
                currentMenuState = MenuState.SHOWING;
                menuScroller.startScroll(contentXOffset, 0,
                        menu.getLayoutParams().width - contentXOffset, 0,
                        SLIDING_DURATION);
            } else if (lastDiffX < 0) {
                currentMenuState = MenuState.HIDING;
                menuScroller.startScroll(contentXOffset, 0, -contentXOffset, 0,
                        SLIDING_DURATION);
            }
            menuHandler.postDelayed(menuRunnable, QUERY_INTERVAL);
            this.invalidate();
            isDragging = false;
            prevX = 0;
            lastDiffX = 0;
            return true;

        default:
            break;
        }

        return false;
    }
}

这是我的MainActivity代码

  @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);

            mLayout = (MainLayout) this.getLayoutInflater().inflate(R.layout.activity_main, null);
            setContentView(mLayout);
       btMenu = (ImageView) findViewById(R.id.imgLeftMenu);
        btMenu.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                toggleMenu(v);
                Log.e("333xxxx", "333");
            }
        });
    }
 }

这是我的xml布局

<com.example.javedmomin.demo.MainLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/background_dark">

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

               <TextView
                    android:id="@+id/textView"
                    android:layout_width="0dp"
                    android:layout_height="40dp"/>

 </LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:background="@drawable/shadow">
 </LinearLayout>
</com.example.javedmomin.demo.MainLayout>