'home screen'에 해당되는 글 1건

  1. 2011.10.05 Android - Custom Swipe-Fling Scroll View / like home screen view
posted by Solver Full-stack Developer 2011.10.05 17:44
Step 1.create  CustomViewer.java  and custom!

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.widget.Scroller;


public class CustomViewer extends ViewGroup {
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
 private int mScrollX = 0;
private int mCurrentScreen = 0;//현제 창의 위치
 private float mLastMotionX;
 private static final String LOG_TAG = "FlingAndScrollViewer";
 private static final int SNAP_VELOCITY = 1000;//속도
 private final static int TOUCH_STATE_REST = 0;
private final static int TOUCH_STATE_SCROLLING = 1;
 private int mTouchState = TOUCH_STATE_REST;
 private int mTouchSlop = 0;
 public CustomViewer(Context context) {
    super(context);
    mScroller = new Scroller(context);
     mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
     this.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.FILL_PARENT));
}
 public CustomViewer(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray a = getContext().obtainStyledAttributes(attrs,
            R.styleable.FlingAndScrollViewer);
    mCurrentScreen = a.getInteger(
            R.styleable.FlingAndScrollViewer_default_screen, 0);
     mScroller = new Scroller(context);
     mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
     this.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.FILL_PARENT));
 }
 public void setInitialPosition(int initialPosition){
    mCurrentScreen = initialPosition;
}
 @Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    /*
     * This method JUST determines whether we want to intercept the motion.
     * If we return true, onTouchEvent will be called and we do the actual
     * scrolling there.
     */
     /*
     * Shortcut the most recurring case: the user is in the dragging state
     * and he is moving his finger. We want to intercept this motion.
     */
    final int action = ev.getAction();
    if ((action == MotionEvent.ACTION_MOVE)
            && (mTouchState != TOUCH_STATE_REST)) {
        return true;
    }
     final float x = ev.getX();
     switch (action) {
    case MotionEvent.ACTION_MOVE:
        /*
         * mIsBeingDragged == false, otherwise the shortcut would have
         * caught it. Check whether the user has moved far enough from his
         * original down touch.
         */
         /*
         * Locally do absolute value. mLastMotionX is set to the y value of
         * the down event.
         */
        final int xDiff = (int) Math.abs(x - mLastMotionX);
         boolean xMoved = xDiff > mTouchSlop;
         if (xMoved) {
            // Scroll if the user moved far enough along the X axis
            mTouchState = TOUCH_STATE_SCROLLING;
        }
        break;
     case MotionEvent.ACTION_DOWN:
        // Remember location of down touch
        mLastMotionX = x;
         /*
         * If being flinged and user touches the screen, initiate drag;
         * otherwise don't. mScroller.isFinished should be false when being
         * flinged.
         */
        mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
                : TOUCH_STATE_SCROLLING;
        break;
     case MotionEvent.ACTION_CANCEL:
    case MotionEvent.ACTION_UP:
        // Release the drag
        mTouchState = TOUCH_STATE_REST;
        break;
    }
     /*
     * The only time we want to intercept motion events is if we are in the
     * drag mode.
     */
    return mTouchState != TOUCH_STATE_REST;
}
 @Override
public boolean onTouchEvent(MotionEvent event) {
     if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    mVelocityTracker.addMovement(event);
     final int action = event.getAction();
    final float x = event.getX();
     switch (action) {
    case MotionEvent.ACTION_DOWN:
        Log.i(LOG_TAG, "event : down");
        /*
         * If being flinged and user touches, stop the fling. isFinished
         * will be false if being flinged.
         */
        if (!mScroller.isFinished()) {
            mScroller.abortAnimation();
        }
         // Remember where the motion event started
        mLastMotionX = x;
        break;
    case MotionEvent.ACTION_MOVE:
        // Log.i(LOG_TAG,"event : move");
        // if (mTouchState == TOUCH_STATE_SCROLLING) {
        // Scroll to follow the motion event
        final int deltaX = (int) (mLastMotionX - x);
        mLastMotionX = x;
         // Log.i(LOG_TAG, "event : move, deltaX " + deltaX + ", mScrollX " +
        // mScrollX);
         if (deltaX < 0) {
            if (mScrollX > 0) {
                scrollBy(Math.max(-mScrollX, deltaX), 0);
            }
        } else if (deltaX > 0) {
            final int availableToScroll = getChildAt(getChildCount() - 1)
                    .getRight() - mScrollX - getWidth();
            if (availableToScroll > 0) {
                scrollBy(Math.min(availableToScroll, deltaX), 0);
            }
        }
        // }
        break;
    case MotionEvent.ACTION_UP:
        Log.i(LOG_TAG, "event : up");
        // if (mTouchState == TOUCH_STATE_SCROLLING) {
        final VelocityTracker velocityTracker = mVelocityTracker;
        velocityTracker.computeCurrentVelocity(1000);
        int velocityX = (int) velocityTracker.getXVelocity();
         if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
            // Fling hard enough to move left
            snapToScreen(mCurrentScreen - 1);
        } else if (velocityX < -SNAP_VELOCITY
                && mCurrentScreen < getChildCount() - 1) {
            // Fling hard enough to move right
            snapToScreen(mCurrentScreen + 1);
        } else {
            snapToDestination();
        }
         if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }
        // }
        mTouchState = TOUCH_STATE_REST;
        break;
    case MotionEvent.ACTION_CANCEL:
        Log.i(LOG_TAG, "event : cancel");
        mTouchState = TOUCH_STATE_REST;
    }
    mScrollX = this.getScrollX();
     return true;
}
 private void snapToDestination() {
    final int screenWidth = getWidth();
    final int whichScreen = (mScrollX + (screenWidth / 2)) / screenWidth;
    Log.i(LOG_TAG, "from des");
    snapToScreen(whichScreen);
}
 public void snapToScreen(int whichScreen) {
    Log.i(LOG_TAG, "snap To Screen " + whichScreen);
    mCurrentScreen = whichScreen;
    final int newX = whichScreen * getWidth();
    final int delta = newX - mScrollX;
    mScroller.startScroll(mScrollX, 0, delta, 0, Math.abs(delta) * 2);
    invalidate();
}
 public void setToScreen(int whichScreen) {
    Log.i(LOG_TAG, "set To Screen " + whichScreen);
    mCurrentScreen = whichScreen;
    final int newX = whichScreen * getWidth();
    mScroller.startScroll(newX, 0, 0, 0, 10);
    invalidate();
}
 @Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int childLeft = 0;
     final int count = getChildCount();
    for (int i = 0; i < count; i++) {
        final View child = getChildAt(i);
        if (child.getVisibility() != View.GONE) {
            final int childWidth = child.getMeasuredWidth();
            child.layout(childLeft, 0, childLeft + childWidth,
                    child.getMeasuredHeight());
            childLeft += childWidth;
        }
    }
 }
 @Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     final int width = MeasureSpec.getSize(widthMeasureSpec);
    final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    if (widthMode != MeasureSpec.EXACTLY) {
        throw new IllegalStateException("error mode.");
    }
     final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    if (heightMode != MeasureSpec.EXACTLY) {
        throw new IllegalStateException("error mode.");
    }
     // The children are given the same width and height as the workspace
    final int count = getChildCount();
    for (int i = 0; i < count; i++) {
        getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
    }
    Log.i(LOG_TAG, "moving to screen " + mCurrentScreen);
    scrollTo(mCurrentScreen * width, 0);
}
 @Override
public void computeScroll() {
    if (mScroller.computeScrollOffset()) {
        mScrollX = mScroller.getCurrX();
        scrollTo(mScrollX, 0);
        postInvalidate();
    }
}
 /**
 * Return the parceable instance to be saved
 */
@Override
protected Parcelable onSaveInstanceState() {
    final SavedState state = new SavedState(super.onSaveInstanceState());
    state.currentScreen = mCurrentScreen;
    return state;
}
 /**
 * Restore the previous saved current screen
 */
@Override
protected void onRestoreInstanceState(Parcelable state) {
    SavedState savedState = (SavedState) state;
    super.onRestoreInstanceState(savedState.getSuperState());
    if (savedState.currentScreen != -1) {
        mCurrentScreen = savedState.currentScreen;
    }
}
 // ========================= INNER CLASSES ==============================
 public interface onViewChangedEvent {
    void onViewChange(int currentViewIndex);
}
 /**
 * A SavedState which save and load the current screen
 */
public static class SavedState extends BaseSavedState {
    int currentScreen = -1;
     /**
     * Internal constructor
     *
     * @param superState
     */
    SavedState(Parcelable superState) {
        super(superState);
    }
     /**
     * Private constructor
     *
     * @param in
     */
    private SavedState(Parcel in) {
        super(in);
        currentScreen = in.readInt();
    }
     /**
     * Save the current screen
     */
    @Override
    public void writeToParcel(Parcel out, int flags) {
        super.writeToParcel(out, flags);
        out.writeInt(currentScreen);
    }
     /**
     * Return a Parcelable creator
     */
    public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
        public SavedState createFromParcel(Parcel in) {
            return new SavedState(in);
        }
         public SavedState[] newArray(int size) {
            return new SavedState[size];
        }
    };
}

--------------------------------------------------------------------------------
Step 2. Add attrs
add res/values/attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="CustomViewer">
        <attr name="default_screen" format="integer"/>
    </declare-styleable>
</resources> 
--------------------------------------------------------------------------------
Step 3. Use u r layout!
ex)res/layout/main.xml 
<com.xxxx.xxxx.CustomViewer
        android:layout_width="fill_parent" android:layout_height="fill_parent"
        android:id="@+id/flingScrollViewer"/> 

안녕하세요 ^^
설명을 조금 해보겠습니다.

이 커스텀 UI를 사용하면 폰에서 홈스크린처럼 다음페이지,현제페이지, 전페이지를 스크롤 이동하면 모두보이는 기능입니다. 말이좀 이상한가요?
홈스크린이나 포토 갤러리와 같은 layout이라는 것입니다.

fling할때 가속도와 horizental scroll을 적절히 사용되었습니다.

도움되셧길 바랍니다.

즐코딩! 낫빡침! 

 
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