在项目里面要用到刷新库。曾经都是使用第三方的。只是看到官方出了
因为布局我们改，所以上拉刷新的时候。还是顶部滚动栏出现
SwipeRefreshLayout之后就用SwipeRefreshLayout。可是不知道什么原因官方SwipeRefreshLayout仅仅提供下拉刷新功能，非常多时候我们须要上拉刷新功能。所下面载v4源代码改动SwipeRefreshLayout。与之相关联的文件有两个各自是SwipeProgressBar，BakedBezierInterpolator把这三个文件复制到项目里面，改动一下包名就能够了。
怎样实现上拉刷新功能。事实上我们看一下onInterceptTouchEvent和onTouchEvent就明确了，改的地方也不多。
1、仿canChildScrollUp()函数写canChildScrollDown()用来推断一下能否够上拉。这里我仅仅处理api>14的。由于项目最低版本号是14的。所以我也就没有处理<14的情况
/**
* 检查能否够上拉,对于版本号14下面的暂不支持
* @return
*/
public boolean canChildScrollDown() {
if (android.os.Build.VERSION.SDK_INT < 14) {
if (mTarget instanceof AbsListView) {
final AbsListView absListView = (AbsListView) mTarget;
//仿照canChildScrollUp中的这部分，推断加入<14的代码
} else {
return mTarget.getScrollY() > 0;
}
} else {
return ViewCompat.canScrollVertically(mTarget, 1);
}
}
2、改动onInterceptTouchEvent。加入&& (!canChildScrollUp() || !canChildScrollDown()
@Override public boolean onInterceptTouchEvent(MotionEvent ev) { ensureTarget(); boolean handled = false; if (mReturningToStart && ev.getAction() == MotionEvent.ACTION_DOWN) { mReturningToStart = false; } if (isEnabled() && !mReturningToStart && (!canChildScrollUp() || !canChildScrollDown())) { handled = onTouchEvent(ev); } return !handled ? super.onInterceptTouchEvent(ev) : handled; }
3、改动onTouchEvent，仅仅要在 float yDiff = eventY - mDownEvent.getY();以下加入
if (!canChildScrollDown()) {
yDiff = -eventY + mDownEvent.getY();
}
4、总体的代码例如以下：
/*
* Copyright (C) 2013 The Android Open Source Project
*
* 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.jwzhangjie.baseui.widget;
import android.view.animation.Interpolator;
/**
* A pre-baked bezier-curved interpolator for indeterminate progress animations.
*/
final class BakedBezierInterpolator implements Interpolator {
private static final BakedBezierInterpolator INSTANCE = new BakedBezierInterpolator();
public final static BakedBezierInterpolator getInstance() {
return INSTANCE;
}
/**
* Use getInstance instead of instantiating.
*/
private BakedBezierInterpolator() {
super();
}
/**
* Lookup table values.
* Generated using a Bezier curve from (0,0) to (1,1) with control points:
* P0 (0,0)
* P1 (0.4, 0)
* P2 (0.2, 1.0)
* P3 (1.0, 1.0)
*
* Values sampled with x at regular intervals between 0 and 1.
*/
private static final float[] VALUES = new float[] {
0.0f, 0.0002f, 0.0009f, 0.0019f, 0.0036f, 0.0059f, 0.0086f, 0.0119f, 0.0157f, 0.0209f,
0.0257f, 0.0321f, 0.0392f, 0.0469f, 0.0566f, 0.0656f, 0.0768f, 0.0887f, 0.1033f, 0.1186f,
0.1349f, 0.1519f, 0.1696f, 0.1928f, 0.2121f, 0.237f, 0.2627f, 0.2892f, 0.3109f, 0.3386f,
0.3667f, 0.3952f, 0.4241f, 0.4474f, 0.4766f, 0.5f, 0.5234f, 0.5468f, 0.5701f, 0.5933f,
0.6134f, 0.6333f, 0.6531f, 0.6698f, 0.6891f, 0.7054f, 0.7214f, 0.7346f, 0.7502f, 0.763f,
0.7756f, 0.7879f, 0.8f, 0.8107f, 0.8212f, 0.8326f, 0.8415f, 0.8503f, 0.8588f, 0.8672f,
0.8754f, 0.8833f, 0.8911f, 0.8977f, 0.9041f, 0.9113f, 0.9165f, 0.9232f, 0.9281f, 0.9328f,
0.9382f, 0.9434f, 0.9476f, 0.9518f, 0.9557f, 0.9596f, 0.9632f, 0.9662f, 0.9695f, 0.9722f,
0.9753f, 0.9777f, 0.9805f, 0.9826f, 0.9847f, 0.9866f, 0.9884f, 0.9901f, 0.9917f, 0.9931f,
0.9944f, 0.9955f, 0.9964f, 0.9973f, 0.9981f, 0.9986f, 0.9992f, 0.9995f, 0.9998f, 1.0f, 1.0f
};
private static final float STEP_SIZE = 1.0f / (VALUES.length - 1);
@Override
public float getInterpolation(float input) {
if (input >= 1.0f) {
return 1.0f;
}
if (input <= 0f) {
return 0f;
}
int position = Math.min(
(int)(input * (VALUES.length - 1)),
VALUES.length - 2);
float quantized = position * STEP_SIZE;
float difference = input - quantized;
float weight = difference / STEP_SIZE;
return VALUES[position] + weight * (VALUES[position + 1] - VALUES[position]);
}
}
/*
* Copyright (C) 2013 The Android Open Source Project
*
* 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.jwzhangjie.baseui.widget;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.support.v4.view.ViewCompat;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
/**
* Custom progress bar that shows a cycle of colors as widening circles that
* overdraw each other. When finished, the bar is cleared from the inside out as
* the main cycle continues. Before running, this can also indicate how close
* the user is to triggering something (e.g. how far they need to pull down to
* trigger a refresh).
*/
final class SwipeProgressBar {
// Default progress animation colors are grays.
private final static int COLOR1 = 0xB3000000;
private final static int COLOR2 = 0x80000000;
private final static int COLOR3 = 0x4d000000;
private final static int COLOR4 = 0x1a000000;
// The duration of the animation cycle.
private static final int ANIMATION_DURATION_MS = 2000;
// The duration of the animation to clear the bar.
private static final int FINISH_ANIMATION_DURATION_MS = 1000;
// Interpolator for varying the speed of the animation.
private static final Interpolator INTERPOLATOR = BakedBezierInterpolator.getInstance();
private final Paint mPaint = new Paint();
private final RectF mClipRect = new RectF();
private float mTriggerPercentage;
private long mStartTime;
private long mFinishTime;
private boolean mRunning;
// Colors used when rendering the animation,
private int mColor1;
private int mColor2;
private int mColor3;
private int mColor4;
private View mParent;
private Rect mBounds = new Rect();
public SwipeProgressBar(View parent) {
mParent = parent;
mColor1 = COLOR1;
mColor2 = COLOR2;
mColor3 = COLOR3;
mColor4 = COLOR4;
}
/**
* Set the four colors used in the progress animation. The first color will
* also be the color of the bar that grows in response to a user swipe
* gesture.
*
* @param color1 Integer representation of a color.
* @param color2 Integer representation of a color.
* @param color3 Integer representation of a color.
* @param color4 Integer representation of a color.
*/
void setColorScheme(int color1, int color2, int color3, int color4) {
mColor1 = color1;
mColor2 = color2;
mColor3 = color3;
mColor4 = color4;
}
/**
* Update the progress the user has made toward triggering the swipe
* gesture. and use this value to update the percentage of the trigger that
* is shown.
*/
void setTriggerPercentage(float triggerPercentage) {
mTriggerPercentage = triggerPercentage;
mStartTime = 0;
ViewCompat.postInvalidateOnAnimation(mParent);
}
/**
* Start showing the progress animation.
*/
void start() {
if (!mRunning) {
mTriggerPercentage = 0;
mStartTime = AnimationUtils.currentAnimationTimeMillis();
mRunning = true;
mParent.postInvalidate();
}
}
/**
* Stop showing the progress animation.
*/
void stop() {
if (mRunning) {
mTriggerPercentage = 0;
mFinishTime = AnimationUtils.currentAnimationTimeMillis();
mRunning = false;
mParent.postInvalidate();
}
}
/**
* @return Return whether the progress animation is currently running.
*/
boolean isRunning() {
return mRunning || mFinishTime > 0;
}
void draw(Canvas canvas) {
final int width = mBounds.width();
final int height = mBounds.height();
final int cx = width / 2;
final int cy = height / 2;
boolean drawTriggerWhileFinishing = false;
int restoreCount = canvas.save();
canvas.clipRect(mBounds);
if (mRunning || (mFinishTime > 0)) {
long now = AnimationUtils.currentAnimationTimeMillis();
long elapsed = (now - mStartTime) % ANIMATION_DURATION_MS;
long iterations = (now - mStartTime) / ANIMATION_DURATION_MS;
float rawProgress = (elapsed / (ANIMATION_DURATION_MS / 100f));
// If we're not running anymore, that means we're running through
// the finish animation.
if (!mRunning) {
// If the finish animation is done, don't draw anything, and
// don't repost.
if ((now - mFinishTime) >= FINISH_ANIMATION_DURATION_MS) {
mFinishTime = 0;
return;
}
// Otherwise, use a 0 opacity alpha layer to clear the animation
// from the inside out. This layer will prevent the circles from
// drawing within its bounds.
long finishElapsed = (now - mFinishTime) % FINISH_ANIMATION_DURATION_MS;
float finishProgress = (finishElapsed / (FINISH_ANIMATION_DURATION_MS / 100f));
float pct = (finishProgress / 100f);
// Radius of the circle is half of the screen.
float clearRadius = width / 2 * INTERPOLATOR.getInterpolation(pct);
mClipRect.set(cx - clearRadius, 0, cx + clearRadius, height);
canvas.saveLayerAlpha(mClipRect, 0, 0);
// Only draw the trigger if there is a space in the center of
// this refreshing view that needs to be filled in by the
// trigger. If the progress view is just still animating, let it
// continue animating.
drawTriggerWhileFinishing = true;
}
// First fill in with the last color that would have finished drawing.
if (iterations == 0) {
canvas.drawColor(mColor1);
} else {
if (rawProgress >= 0 && rawProgress < 25) {
canvas.drawColor(mColor4);
} else if (rawProgress >= 25 && rawProgress < 50) {
canvas.drawColor(mColor1);
} else if (rawProgress >= 50 && rawProgress < 75) {
canvas.drawColor(mColor2);
} else {
canvas.drawColor(mColor3);
}
}
// Then draw up to 4 overlapping concentric circles of varying radii, based on how far
// along we are in the cycle.
// progress 0-50 draw mColor2
// progress 25-75 draw mColor3
// progress 50-100 draw mColor4
// progress 75 (wrap to 25) draw mColor1
if ((rawProgress >= 0 && rawProgress <= 25)) {
float pct = (((rawProgress + 25) * 2) / 100f);
drawCircle(canvas, cx, cy, mColor1, pct);
}
if (rawProgress >= 0 && rawProgress <= 50) {
float pct = ((rawProgress * 2) / 100f);
drawCircle(canvas, cx, cy, mColor2, pct);
}
if (rawProgress >= 25 && rawProgress <= 75) {
float pct = (((rawProgress - 25) * 2) / 100f);
drawCircle(canvas, cx, cy, mColor3, pct);
}
if (rawProgress >= 50 && rawProgress <= 100) {
float pct = (((rawProgress - 50) * 2) / 100f);
drawCircle(canvas, cx, cy, mColor4, pct);
}
if ((rawProgress >= 75 && rawProgress <= 100)) {
float pct = (((rawProgress - 75) * 2) / 100f);
drawCircle(canvas, cx, cy, mColor1, pct);
}
if (mTriggerPercentage > 0 && drawTriggerWhileFinishing) {
// There is some portion of trigger to draw. Restore the canvas,
// then draw the trigger. Otherwise, the trigger does not appear
// until after the bar has finished animating and appears to
// just jump in at a larger width than expected.
canvas.restoreToCount(restoreCount);
restoreCount = canvas.save();
canvas.clipRect(mBounds);
drawTrigger(canvas, cx, cy);
}
// Keep running until we finish out the last cycle.
ViewCompat.postInvalidateOnAnimation(mParent);
} else {
// Otherwise if we're in the middle of a trigger, draw that.
if (mTriggerPercentage > 0 && mTriggerPercentage <= 1.0) {
drawTrigger(canvas, cx, cy);
}
}
canvas.restoreToCount(restoreCount);
}
private void drawTrigger(Canvas canvas, int cx, int cy) {
mPaint.setColor(mColor1);
canvas.drawCircle(cx, cy, cx * mTriggerPercentage, mPaint);
}
/**
* Draws a circle centered in the view.
*
* @param canvas the canvas to draw on
* @param cx the center x coordinate
* @param cy the center y coordinate
* @param color the color to draw
* @param pct the percentage of the view that the circle should cover
*/
private void drawCircle(Canvas canvas, float cx, float cy, int color, float pct) {
mPaint.setColor(color);
canvas.save();
canvas.translate(cx, cy);
float radiusScale = INTERPOLATOR.getInterpolation(pct);
canvas.scale(radiusScale, radiusScale);
canvas.drawCircle(0, 0, cx, mPaint);
canvas.restore();
}
/**
* Set the drawing bounds of this SwipeProgressBar.
*/
void setBounds(int left, int top, int right, int bottom) {
mBounds.left = left;
mBounds.top = top;
mBounds.right = right;
mBounds.bottom = bottom;
}
}/*
* Copyright (C) 2013 The Android Open Source Project
*
* 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.jwzhangjie.baseui.widget;
import com.jwzhangjie.baseui.utils.AppLog;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.Animation.AnimationListener;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.Transformation;
import android.widget.AbsListView;
/**
* The SwipeRefreshLayout should be used whenever the user can refresh the
* contents of a view via a vertical swipe gesture. The activity that
* instantiates this view should add an OnRefreshListener to be notified
* whenever the swipe to refresh gesture is completed. The SwipeRefreshLayout
* will notify the listener each and every time the gesture is completed again;
* the listener is responsible for correctly determining when to actually
* initiate a refresh of its content. If the listener determines there should
* not be a refresh, it must call setRefreshing(false) to cancel any visual
* indication of a refresh. If an activity wishes to show just the progress
* animation, it should call setRefreshing(true). To disable the gesture and progress
* animation, call setEnabled(false) on the view.
*
* <p> This layout should be made the parent of the view that will be refreshed as a
* result of the gesture and can only support one direct child. This view will
* also be made the target of the gesture and will be forced to match both the
* width and the height supplied in this layout. The SwipeRefreshLayout does not
* provide accessibility events; instead, a menu item must be provided to allow
* refresh of the content wherever this gesture is used.</p>
*/
public class SwipeRefreshLayout extends ViewGroup {
private static final long RETURN_TO_ORIGINAL_POSITION_TIMEOUT = 300;
private static final float ACCELERATE_INTERPOLATION_FACTOR = 1.5f;
private static final float DECELERATE_INTERPOLATION_FACTOR = 2f;
private static final float PROGRESS_BAR_HEIGHT = 4;
private static final float MAX_SWIPE_DISTANCE_FACTOR = .6f;
private static final int REFRESH_TRIGGER_DISTANCE = 120;
private SwipeProgressBar mProgressBar; //the thing that shows progress is going
private View mTarget; //the content that gets pulled down
private int mOriginalOffsetTop;
private OnRefreshListener mListener;
private MotionEvent mDownEvent;
private int mFrom;
private boolean mRefreshing = false;
private int mTouchSlop;
private float mDistanceToTriggerSync = -1;
private float mPrevY;
private int mMediumAnimationDuration;
private float mFromPercentage = 0;
private float mCurrPercentage = 0;
private int mProgressBarHeight;
private int mCurrentTargetOffsetTop;
// Target is returning to its start offset because it was cancelled or a
// refresh was triggered.
private boolean mReturningToStart;
private final DecelerateInterpolator mDecelerateInterpolator;
private final AccelerateInterpolator mAccelerateInterpolator;
private static final int[] LAYOUT_ATTRS = new int[] {
android.R.attr.enabled
};
private final Animation mAnimateToStartPosition = new Animation() {
@Override
public void applyTransformation(float interpolatedTime, Transformation t) {
int targetTop = 0;
if (mFrom != mOriginalOffsetTop) {
targetTop = (mFrom + (int)((mOriginalOffsetTop - mFrom) * interpolatedTime));
}
int offset = targetTop - mTarget.getTop();
final int currentTop = mTarget.getTop();
if (offset + currentTop < 0) {
offset = 0 - currentTop;
}
setTargetOffsetTopAndBottom(offset);
}
};
private Animation mShrinkTrigger = new Animation() {
@Override
public void applyTransformation(float interpolatedTime, Transformation t) {
float percent = mFromPercentage + ((0 - mFromPercentage) * interpolatedTime);
mProgressBar.setTriggerPercentage(percent);
}
};
private final AnimationListener mReturnToStartPositionListener = new BaseAnimationListener() {
@Override
public void onAnimationEnd(Animation animation) {
// Once the target content has returned to its start position, reset
// the target offset to 0
mCurrentTargetOffsetTop = 0;
}
};
private final AnimationListener mShrinkAnimationListener = new BaseAnimationListener() {
@Override
public void onAnimationEnd(Animation animation) {
mCurrPercentage = 0;
}
};
private final Runnable mReturnToStartPosition = new Runnable() {
@Override
public void run() {
mReturningToStart = true;
animateOffsetToStartPosition(mCurrentTargetOffsetTop + getPaddingTop(),
mReturnToStartPositionListener);
}
};
// Cancel the refresh gesture and animate everything back to its original state.
private final Runnable mCancel = new Runnable() {
@Override
public void run() {
mReturningToStart = true;
// Timeout fired since the user last moved their finger; animate the
// trigger to 0 and put the target back at its original position
if (mProgressBar != null) {
mFromPercentage = mCurrPercentage;
mShrinkTrigger.setDuration(mMediumAnimationDuration);
mShrinkTrigger.setAnimationListener(mShrinkAnimationListener);
mShrinkTrigger.reset();
mShrinkTrigger.setInterpolator(mDecelerateInterpolator);
startAnimation(mShrinkTrigger);
}
animateOffsetToStartPosition(mCurrentTargetOffsetTop + getPaddingTop(),
mReturnToStartPositionListener);
}
};
/**
* Simple constructor to use when creating a SwipeRefreshLayout from code.
* @param context
*/
public SwipeRefreshLayout(Context context) {
this(context, null);
}
/**
* Constructor that is called when inflating SwipeRefreshLayout from XML.
* @param context
* @param attrs
*/
public SwipeRefreshLayout(Context context, AttributeSet attrs) {
super(context, attrs);
mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
mMediumAnimationDuration = getResources().getInteger(
android.R.integer.config_mediumAnimTime);
setWillNotDraw(false);
mProgressBar = new SwipeProgressBar(this);
final DisplayMetrics metrics = getResources().getDisplayMetrics();
mProgressBarHeight = (int) (metrics.density * PROGRESS_BAR_HEIGHT);
mDecelerateInterpolator = new DecelerateInterpolator(DECELERATE_INTERPOLATION_FACTOR);
mAccelerateInterpolator = new AccelerateInterpolator(ACCELERATE_INTERPOLATION_FACTOR);
final TypedArray a = context.obtainStyledAttributes(attrs, LAYOUT_ATTRS);
setEnabled(a.getBoolean(0, true));
a.recycle();
}
@Override
public void onAttachedToWindow() {
super.onAttachedToWindow();
removeCallbacks(mCancel);
removeCallbacks(mReturnToStartPosition);
}
@Override
public void onDetachedFromWindow() {
super.onDetachedFromWindow();
removeCallbacks(mReturnToStartPosition);
removeCallbacks(mCancel);
}
private void animateOffsetToStartPosition(int from, AnimationListener listener) {
mFrom = from;
mAnimateToStartPosition.reset();
mAnimateToStartPosition.setDuration(mMediumAnimationDuration);
mAnimateToStartPosition.setAnimationListener(listener);
mAnimateToStartPosition.setInterpolator(mDecelerateInterpolator);
mTarget.startAnimation(mAnimateToStartPosition);
}
/**
* Set the listener to be notified when a refresh is triggered via the swipe
* gesture.
*/
public void setOnRefreshListener(OnRefreshListener listener) {
mListener = listener;
}
private void setTriggerPercentage(float percent) {
if (percent == 0f) {
// No-op. A null trigger means it's uninitialized, and setting it to zero-percent
// means we're trying to reset state, so there's nothing to reset in this case.
mCurrPercentage = 0;
return;
}
mCurrPercentage = percent;
mProgressBar.setTriggerPercentage(percent);
}
/**
* Notify the widget that refresh state has changed. Do not call this when
* refresh is triggered by a swipe gesture.
*
* @param refreshing Whether or not the view should show refresh progress.
*/
public void setRefreshing(boolean refreshing) {
if (mRefreshing != refreshing) {
ensureTarget();
mCurrPercentage = 0;
mRefreshing = refreshing;
if (mRefreshing) {
mProgressBar.start();
} else {
mProgressBar.stop();
}
}
}
/**
* Set the four colors used in the progress animation. The first color will
* also be the color of the bar that grows in response to a user swipe
* gesture.
*
* @param colorRes1 Color resource.
* @param colorRes2 Color resource.
* @param colorRes3 Color resource.
* @param colorRes4 Color resource.
*/
public void setColorScheme(int colorRes1, int colorRes2, int colorRes3, int colorRes4) {
ensureTarget();
final Resources res = getResources();
final int color1 = res.getColor(colorRes1);
final int color2 = res.getColor(colorRes2);
final int color3 = res.getColor(colorRes3);
final int color4 = res.getColor(colorRes4);
mProgressBar.setColorScheme(color1, color2, color3,color4);
}
/**
* @return Whether the SwipeRefreshWidget is actively showing refresh
* progress.
*/
public boolean isRefreshing() {
return mRefreshing;
}
private void ensureTarget() {
// Don't bother getting the parent height if the parent hasn't been laid out yet.
if (mTarget == null) {
if (getChildCount() > 1 && !isInEditMode()) {
throw new IllegalStateException(
"SwipeRefreshLayout can host only one direct child");
}
mTarget = getChildAt(0);
mOriginalOffsetTop = mTarget.getTop() + getPaddingTop();
}
if (mDistanceToTriggerSync == -1) {
if (getParent() != null && ((View)getParent()).getHeight() > 0) {
final DisplayMetrics metrics = getResources().getDisplayMetrics();
mDistanceToTriggerSync = (int) Math.min(
((View) getParent()) .getHeight() * MAX_SWIPE_DISTANCE_FACTOR,
REFRESH_TRIGGER_DISTANCE * metrics.density);
}
}
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
mProgressBar.draw(canvas);
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
final int width = getMeasuredWidth();
final int height = getMeasuredHeight();
mProgressBar.setBounds(0, 0, width, mProgressBarHeight);
if (getChildCount() == 0) {
return;
}
final View child = getChildAt(0);
final int childLeft = getPaddingLeft();
final int childTop = mCurrentTargetOffsetTop + getPaddingTop();
final int childWidth = width - getPaddingLeft() - getPaddingRight();
final int childHeight = height - getPaddingTop() - getPaddingBottom();
child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
}
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (getChildCount() > 1 && !isInEditMode()) {
throw new IllegalStateException("SwipeRefreshLayout can host only one direct child");
}
if (getChildCount() > 0) {
getChildAt(0).measure(
MeasureSpec.makeMeasureSpec(
getMeasuredWidth() - getPaddingLeft() - getPaddingRight(),
MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(
getMeasuredHeight() - getPaddingTop() - getPaddingBottom(),
MeasureSpec.EXACTLY));
}
}
/**
* @return Whether it is possible for the child view of this layout to
* scroll up. Override this if the child view is a custom view.
*/
public boolean canChildScrollUp() {
if (android.os.Build.VERSION.SDK_INT < 14) {
if (mTarget instanceof AbsListView) {
final AbsListView absListView = (AbsListView) mTarget;
return absListView.getChildCount() > 0
&& (absListView.getFirstVisiblePosition() > 0 || absListView.getChildAt(0)
.getTop() < absListView.getPaddingTop());
} else {
return mTarget.getScrollY() > 0;
}
} else {
return ViewCompat.canScrollVertically(mTarget, -1);
}
}
/**
* 检查能否够上拉,对于版本号14下面的暂不支持
* @return
*/
public boolean canChildScrollDown() {
if (android.os.Build.VERSION.SDK_INT < 14) {
if (mTarget instanceof AbsListView) {
final AbsListView absListView = (AbsListView) mTarget;
AppLog.e(absListView.getFirstVisiblePosition()+" : "+absListView.getChildAt(absListView.getChildCount()-1).getBottom()+" : "+absListView.getPaddingBottom());
return absListView.getChildCount() > 0
&& (absListView.getFirstVisiblePosition() > 0 || absListView.getChildAt(0)
.getTop() < absListView.getPaddingTop());
} else {
return mTarget.getScrollY() > 0;
}
} else {
return ViewCompat.canScrollVertically(mTarget, 1);
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
ensureTarget();
boolean handled = false;
if (mReturningToStart && ev.getAction() == MotionEvent.ACTION_DOWN) {
mReturningToStart = false;
}
if (isEnabled() && !mReturningToStart && (!canChildScrollUp() || !canChildScrollDown())) {
handled = onTouchEvent(ev);
}
return !handled ? super.onInterceptTouchEvent(ev) : handled;
}
@Override
public void requestDisallowInterceptTouchEvent(boolean b) {
// Nope.
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int action = event.getAction();
boolean handled = false;
switch (action) {
case MotionEvent.ACTION_DOWN:
mCurrPercentage = 0;
mDownEvent = MotionEvent.obtain(event);
mPrevY = mDownEvent.getY();
break;
case MotionEvent.ACTION_MOVE:
AppLog.e(mTarget.getBottom()+" bottom");
if (mDownEvent != null && !mReturningToStart) {
final float eventY = event.getY();
float yDiff = eventY - mDownEvent.getY();
if (!canChildScrollDown()) {
yDiff = -eventY + mDownEvent.getY();
}
if (yDiff > mTouchSlop) {
// User velocity passed min velocity; trigger a refresh
if (yDiff > mDistanceToTriggerSync) {
// User movement passed distance; trigger a refresh
startRefresh();
handled = true;
break;
} else {
// Just track the user's movement
setTriggerPercentage(
mAccelerateInterpolator.getInterpolation(
yDiff / mDistanceToTriggerSync));
float offsetTop = yDiff;
if (mPrevY > eventY) {
offsetTop = yDiff - mTouchSlop;
}
updateContentOffsetTop((int) (offsetTop));
if (mPrevY > eventY && (mTarget.getTop() < mTouchSlop)) {
// If the user puts the view back at the top, we
// don't need to. This shouldn't be considered
// cancelling the gesture as the user can restart from the top.
removeCallbacks(mCancel);
} else {
updatePositionTimeout();
}
mPrevY = event.getY();
handled = true;
}
}
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
if (mDownEvent != null) {
mDownEvent.recycle();
mDownEvent = null;
}
break;
}
return handled;
}
private void startRefresh() {
removeCallbacks(mCancel);
mReturnToStartPosition.run();
setRefreshing(true);
mListener.onRefresh();
}
private void updateContentOffsetTop(int targetTop) {
final int currentTop = mTarget.getTop();
if (targetTop > mDistanceToTriggerSync) {
targetTop = (int) mDistanceToTriggerSync;
} else if (targetTop < 0) {
targetTop = 0;
}
setTargetOffsetTopAndBottom(targetTop - currentTop);
}
private void setTargetOffsetTopAndBottom(int offset) {
mTarget.offsetTopAndBottom(offset);
mCurrentTargetOffsetTop = mTarget.getTop();
}
private void updatePositionTimeout() {
removeCallbacks(mCancel);
postDelayed(mCancel, RETURN_TO_ORIGINAL_POSITION_TIMEOUT);
}
/**
* Classes that wish to be notified when the swipe gesture correctly
* triggers a refresh should implement this interface.
*/
public interface OnRefreshListener {
public void onRefresh();
}
/**
* Simple AnimationListener to avoid having to implement unneeded methods in
* AnimationListeners.
*/
private class BaseAnimationListener implements AnimationListener {
@Override
public void onAnimationStart(Animation animation) {
}
@Override
public void onAnimationEnd(Animation animation) {
}
@Override
public void onAnimationRepeat(Animation animation) {
}
}
}因为布局我们改，所以上拉刷新的时候。还是顶部滚动栏出现