Java tutorial
/* * Copyright (c) 2015 [1076559197@qq.com | tchen0707@gmail.com] * * Licensed under the Apache License, Version 2.0 (the "License?); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.papa.library.swipeback; import android.app.Activity; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Rect; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.widget.FrameLayout; import com.papa.library.R; import java.util.ArrayList; import java.util.List; public class SwipeBackLayout extends FrameLayout { /** * Minimum velocity that will be detected as a fling */ private static final int MIN_FLING_VELOCITY = 400; // dips per second private static final int DEFAULT_SCRIM_COLOR = 0x99000000; private static final int FULL_ALPHA = 255; /** * Edge flag indicating that the left edge should be affected. */ public static final int EDGE_LEFT = ViewDragHelper.EDGE_LEFT; /** * Edge flag indicating that the right edge should be affected. */ public static final int EDGE_RIGHT = ViewDragHelper.EDGE_RIGHT; /** * Edge flag indicating that the bottom edge should be affected. */ public static final int EDGE_BOTTOM = ViewDragHelper.EDGE_BOTTOM; /** * Edge flag set indicating all edges should be affected. */ public static final int EDGE_ALL = EDGE_LEFT | EDGE_RIGHT | EDGE_BOTTOM; /** * A view is not currently being dragged or animating as a result of a * fling/snap. */ public static final int STATE_IDLE = ViewDragHelper.STATE_IDLE; /** * A view is currently being dragged. The position is currently changing as * a result of user input or simulated user input. */ public static final int STATE_DRAGGING = ViewDragHelper.STATE_DRAGGING; /** * A view is currently settling into place as a result of a fling or * predefined non-interactive motion. */ public static final int STATE_SETTLING = ViewDragHelper.STATE_SETTLING; /** * Default threshold of scroll */ private static final float DEFAULT_SCROLL_THRESHOLD = 0.3f; private static final int OVERSCROLL_DISTANCE = 10; private static final int[] EDGE_FLAGS = { EDGE_LEFT, EDGE_RIGHT, EDGE_BOTTOM, EDGE_ALL }; private int mEdgeFlag; /** * Threshold of scroll, we will close the activity, when scrollPercent over * this value; */ private float mScrollThreshold = DEFAULT_SCROLL_THRESHOLD; private Activity mActivity; private boolean mEnable = true; private View mContentView; private ViewDragHelper mDragHelper; private float mScrollPercent; private int mContentLeft; private int mContentTop; /** * The set of listeners to be sent events through. */ private List<SwipeListener> mListeners; private float mScrimOpacity; private int mScrimColor = DEFAULT_SCRIM_COLOR; private boolean mInLayout; private Rect mTmpRect = new Rect(); /** * Edge being dragged */ private int mTrackingEdge; public SwipeBackLayout(Context context) { this(context, null); } public SwipeBackLayout(Context context, AttributeSet attrs) { this(context, attrs, R.attr.SwipeBackLayoutStyle); } public SwipeBackLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs); mDragHelper = ViewDragHelper.create(this, new ViewDragCallback()); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SwipeBackLayout, defStyle, R.style.SwipeBackLayout); int edgeSize = a.getDimensionPixelSize(R.styleable.SwipeBackLayout_edge_size, -1); if (edgeSize > 0) setEdgeSize(edgeSize); int mode = EDGE_FLAGS[a.getInt(R.styleable.SwipeBackLayout_edge_flag, 0)]; setEdgeTrackingEnabled(mode); a.recycle(); final float density = getResources().getDisplayMetrics().density; final float minVel = MIN_FLING_VELOCITY * density; mDragHelper.setMinVelocity(minVel); mDragHelper.setMaxVelocity(minVel * 2f); } /** * Sets the sensitivity of the NavigationLayout. * * @param context The application context. * @param sensitivity value between 0 and 1, the final value for touchSlop = * ViewConfiguration.getScaledTouchSlop * (1 / s); */ public void setSensitivity(Context context, float sensitivity) { mDragHelper.setSensitivity(context, sensitivity); } /** * Set up contentView which will be moved by user gesture * * @param view */ private void setContentView(View view) { mContentView = view; } public void setEnableGesture(boolean enable) { mEnable = enable; } /** * Enable edge tracking for the selected edges of the parent view. The * callback's * {@link com.github.obsessive.library.swipeback.ViewDragHelper.Callback#onEdgeTouched(int, int)} * and * {@link com.github.obsessive.library.swipeback.ViewDragHelper.Callback#onEdgeDragStarted(int, int)} * methods will only be invoked for edges for which edge tracking has been * enabled. * * @param edgeFlags Combination of edge flags describing the edges to watch * @see #EDGE_LEFT * @see #EDGE_RIGHT * @see #EDGE_BOTTOM */ public void setEdgeTrackingEnabled(int edgeFlags) { mEdgeFlag = edgeFlags; mDragHelper.setEdgeTrackingEnabled(mEdgeFlag); } /** * Set a color to use for the scrim that obscures primary content while a * drawer is open. * * @param color Color to use in 0xAARRGGBB format. */ public void setScrimColor(int color) { mScrimColor = color; invalidate(); } /** * Set the size of an edge. This is the range in pixels along the edges of * this view that will actively detect edge touches or drags if edge * tracking is enabled. * * @param size The size of an edge in pixels */ public void setEdgeSize(int size) { mDragHelper.setEdgeSize(size); } /** * Register a callback to be invoked when a swipe event is sent to this * view. * * @param listener the swipe listener to attach to this view * @deprecated use {@link #addSwipeListener} instead */ @Deprecated public void setSwipeListener(SwipeListener listener) { addSwipeListener(listener); } /** * Add a callback to be invoked when a swipe event is sent to this view. * * @param listener the swipe listener to attach to this view */ public void addSwipeListener(SwipeListener listener) { if (mListeners == null) { mListeners = new ArrayList<SwipeListener>(); } mListeners.add(listener); } /** * Removes a listener from the set of listeners * * @param listener */ public void removeSwipeListener(SwipeListener listener) { if (mListeners == null) { return; } mListeners.remove(listener); } public static interface SwipeListener { /** * Invoke when state change * * @param state flag to describe scroll state * @param scrollPercent scroll percent of this view * @see #STATE_IDLE * @see #STATE_DRAGGING * @see #STATE_SETTLING */ public void onScrollStateChange(int state, float scrollPercent); /** * Invoke when edge touched * * @param edgeFlag edge flag describing the edge being touched * @see #EDGE_LEFT * @see #EDGE_RIGHT * @see #EDGE_BOTTOM */ public void onEdgeTouch(int edgeFlag); /** * Invoke when scroll percent over the threshold for the first time */ public void onScrollOverThreshold(); } /** * Set scroll threshold, we will close the activity, when scrollPercent over * this value * * @param threshold */ public void setScrollThresHold(float threshold) { if (threshold >= 1.0f || threshold <= 0) { throw new IllegalArgumentException("Threshold value should be between 0 and 1.0"); } mScrollThreshold = threshold; } /** * Scroll out contentView and finish the activity */ public void scrollToFinishActivity() { final int childWidth = mContentView.getWidth(); final int childHeight = mContentView.getHeight(); int left = 0, top = 0; if ((mEdgeFlag & EDGE_LEFT) != 0) { left = childWidth + OVERSCROLL_DISTANCE; mTrackingEdge = EDGE_LEFT; } else if ((mEdgeFlag & EDGE_RIGHT) != 0) { left = -childWidth - OVERSCROLL_DISTANCE; mTrackingEdge = EDGE_RIGHT; } else if ((mEdgeFlag & EDGE_BOTTOM) != 0) { top = -childHeight - OVERSCROLL_DISTANCE; mTrackingEdge = EDGE_BOTTOM; } mDragHelper.smoothSlideViewTo(mContentView, left, top); invalidate(); } @Override public boolean onInterceptTouchEvent(MotionEvent event) { if (!mEnable) { return false; } try { return mDragHelper.shouldInterceptTouchEvent(event); } catch (ArrayIndexOutOfBoundsException e) { // FIXME: handle exception // issues #9 return false; } } @Override public boolean onTouchEvent(MotionEvent event) { if (!mEnable) { return false; } mDragHelper.processTouchEvent(event); return true; } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { mInLayout = true; if (mContentView != null) mContentView.layout(mContentLeft, mContentTop, mContentLeft + mContentView.getMeasuredWidth(), mContentTop + mContentView.getMeasuredHeight()); mInLayout = false; } @Override public void requestLayout() { if (!mInLayout) { super.requestLayout(); } } @Override protected boolean drawChild(Canvas canvas, View child, long drawingTime) { final boolean drawContent = child == mContentView; boolean ret = super.drawChild(canvas, child, drawingTime); if (mScrimOpacity > 0 && drawContent && mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE) { drawScrim(canvas, child); } return ret; } private void drawScrim(Canvas canvas, View child) { final int baseAlpha = (mScrimColor & 0xff000000) >>> 24; final int alpha = (int) (baseAlpha * mScrimOpacity); final int color = alpha << 24 | (mScrimColor & 0xffffff); if ((mTrackingEdge & EDGE_LEFT) != 0) { canvas.clipRect(0, 0, child.getLeft(), getHeight()); } else if ((mTrackingEdge & EDGE_RIGHT) != 0) { canvas.clipRect(child.getRight(), 0, getRight(), getHeight()); } else if ((mTrackingEdge & EDGE_BOTTOM) != 0) { canvas.clipRect(child.getLeft(), child.getBottom(), getRight(), getHeight()); } canvas.drawColor(color); } public void attachToActivity(Activity activity) { mActivity = activity; TypedArray a = activity.getTheme().obtainStyledAttributes(new int[] { android.R.attr.windowBackground }); int background = a.getResourceId(0, 0); a.recycle(); ViewGroup decor = (ViewGroup) activity.getWindow().getDecorView().findViewById(Window.ID_ANDROID_CONTENT); ViewGroup decorChild = (ViewGroup) decor.getChildAt(0); decorChild.setBackgroundResource(background); decor.removeView(decorChild); addView(decorChild); setContentView(decorChild); decor.addView(this); } @Override public void computeScroll() { mScrimOpacity = 1 - mScrollPercent; if (mDragHelper.continueSettling(true)) { ViewCompat.postInvalidateOnAnimation(this); } } private class ViewDragCallback extends ViewDragHelper.Callback { private boolean mIsScrollOverValid; @Override public boolean tryCaptureView(View view, int i) { boolean ret = mDragHelper.isEdgeTouched(mEdgeFlag, i); if (ret) { if (mDragHelper.isEdgeTouched(EDGE_LEFT, i)) { mTrackingEdge = EDGE_LEFT; } else if (mDragHelper.isEdgeTouched(EDGE_RIGHT, i)) { mTrackingEdge = EDGE_RIGHT; } else if (mDragHelper.isEdgeTouched(EDGE_BOTTOM, i)) { mTrackingEdge = EDGE_BOTTOM; } if (mListeners != null && !mListeners.isEmpty()) { for (SwipeListener listener : mListeners) { listener.onEdgeTouch(mTrackingEdge); } } mIsScrollOverValid = true; } return ret; } @Override public int getViewHorizontalDragRange(View child) { return mEdgeFlag & (EDGE_LEFT | EDGE_RIGHT); } @Override public int getViewVerticalDragRange(View child) { return mEdgeFlag & EDGE_BOTTOM; } @Override public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) { super.onViewPositionChanged(changedView, left, top, dx, dy); if ((mTrackingEdge & EDGE_LEFT) != 0) { mScrollPercent = Math.abs((float) left / (mContentView.getWidth())); } else if ((mTrackingEdge & EDGE_RIGHT) != 0) { mScrollPercent = Math.abs((float) left / (mContentView.getWidth())); } else if ((mTrackingEdge & EDGE_BOTTOM) != 0) { mScrollPercent = Math.abs((float) top / (mContentView.getHeight())); } mContentLeft = left; mContentTop = top; invalidate(); if (mScrollPercent < mScrollThreshold && !mIsScrollOverValid) { mIsScrollOverValid = true; } if (mListeners != null && !mListeners.isEmpty() && mDragHelper.getViewDragState() == STATE_DRAGGING && mScrollPercent >= mScrollThreshold && mIsScrollOverValid) { mIsScrollOverValid = false; for (SwipeListener listener : mListeners) { listener.onScrollOverThreshold(); } } if (mScrollPercent >= 1) { if (!mActivity.isFinishing()) mActivity.finish(); } } @Override public void onViewReleased(View releasedChild, float xvel, float yvel) { final int childWidth = releasedChild.getWidth(); final int childHeight = releasedChild.getHeight(); int left = 0, top = 0; if ((mTrackingEdge & EDGE_LEFT) != 0) { left = xvel > 0 || xvel == 0 && mScrollPercent > mScrollThreshold ? childWidth + OVERSCROLL_DISTANCE : 0; } else if ((mTrackingEdge & EDGE_RIGHT) != 0) { left = xvel < 0 || xvel == 0 && mScrollPercent > mScrollThreshold ? -(childWidth + OVERSCROLL_DISTANCE) : 0; } else if ((mTrackingEdge & EDGE_BOTTOM) != 0) { top = yvel < 0 || yvel == 0 && mScrollPercent > mScrollThreshold ? -(childHeight + OVERSCROLL_DISTANCE) : 0; } mDragHelper.settleCapturedViewAt(left, top); invalidate(); } @Override public int clampViewPositionHorizontal(View child, int left, int dx) { int ret = 0; if ((mTrackingEdge & EDGE_LEFT) != 0) { ret = Math.min(child.getWidth(), Math.max(left, 0)); } else if ((mTrackingEdge & EDGE_RIGHT) != 0) { ret = Math.min(0, Math.max(left, -child.getWidth())); } return ret; } @Override public int clampViewPositionVertical(View child, int top, int dy) { int ret = 0; if ((mTrackingEdge & EDGE_BOTTOM) != 0) { ret = Math.min(0, Math.max(top, -child.getHeight())); } return ret; } @Override public void onViewDragStateChanged(int state) { super.onViewDragStateChanged(state); if (mListeners != null && !mListeners.isEmpty()) { for (SwipeListener listener : mListeners) { listener.onScrollStateChange(state, mScrollPercent); } } } } }