SoFunction
Updated on 2025-03-11

Android development tutorial: Sliding closing fragment example


package ;

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public class MyView extends ViewGroup {
    View leftView = null;
    View rightView = null;

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        View view = new View(context, attrs);
        ();
        (view, 0);
    }

    /**
* Measurement
     */
    @SuppressLint("DrawAllocation")
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        if (getChildCount() != 2) {
            try {
// Custom Exception
                throw new Exception() {
                    @Override
                    public void printStackTrace() {
("There can only be one View in MyView");
                        ();
                    }

                };
            } catch (Exception e) {
                ();
            }
        }
        leftView = getChildAt(0);
// Set the height and width of leftview
        (widthMeasureSpec, heightMeasureSpec);
        rightView = getChildAt(1);
// Set the height and width of the rightview
        (widthMeasureSpec, heightMeasureSpec);
        (widthMeasureSpec, heightMeasureSpec);
    }

    /**
* Layout
     */
    @SuppressLint("NewApi")
    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        (l + "," + t + "," + r + "," + b);
        if (leftView != null & rightView != null) {
// Set the position of leftview, on the right side of the screen (initially invisible)
            (-r, 0, 0, b);
// Set the position of the rightView, in the screen
            (l, t, r, b);
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        (canvas);

    }

    @SuppressLint("NewApi")
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        final float X = ();
        float Y = ();
        switch (()) {

        case MotionEvent.ACTION_MOVE:
            ("X:" + X);
            if (X < 100) {
                scrollTo(0, 0);
} else if (X > () - 100) {// When the user slides to 100 from the right edge, the page closes
new Thread(new Runnable() {// Create a new thread, slide to close
                            @Override
                            public void run() {
                                for (int i = 0;; i++) {
                                    try {
(10);// RightView moves right 3 every 10ms to ensure smooth sliding
                                    } catch (InterruptedException e) {
                                        ();
                                    }
                                    int len = (int) (X + 3 * i);
                                    // ("len:" + len);
Message message = new Message();// Non-UI threads in Android do not allow direct operation of controls, and messages can be sent to the handler class of the main thread
                                    if (len >= ()) {
                                        = 1;
(message);// Send a message
// Close View
                                        break;
                                    } else {
= 0; // Send message Automatically swipe
                                        (message);
                                    }
                                }
                            }
                        }).start();
            } else {
                scrollTo((int) -X, 0);
// Calculate transparency information
                float alpha = (float) (1.0 - (float) (1.0 / 400) * X);
                // ("alpha:" + al);
// Set transparency
                (alpha);
            }
            break;
        }
// Set true, consume event events, not to be passed out
        return true;
    }

    @SuppressLint("HandlerLeak")
    Handler handler = new Handler() {
        @SuppressLint("NewApi")
        @Override
        public void handleMessage(Message msg) {
            if ( == 0) {
scrollBy(-3, 0);// viewgroup swipes right 3
            } else if ( == 1) {
(getContext(), "Close", 50).show();
setVisibility();// Set viewgroup invisible (hidden)
            }
        }

    };
}