android刷新组件,亲自动手编写Android通用刷新控件

项目中我们经常有上拉、下拉刷新的需求，几乎所有的listView、RecyclerView都会伴随着上拉、下拉刷新的需求，如果我们使用一些开源控件，换了控件我们就要更新，现在我们自己撸起袖子写一个通用的刷新控件

思路：

写一个继承RelativeLayout的RefreshLayout

添加头尾控件作为刷新控件

通过事件分发来进行刷新操作

通过动画来控制控件移动

目的：让他的所有子控件都可以使用，哪怕是一个TextView

public class RefreshLayout extends RelativeLayout {

/**

* 滑动控件时拉去的速度比例

*/

private final int V_REFRESH = 2;

/**

* 是否是刷新过程

* true 是

* false 不是

* 为false的时候才可以进行刷新

*/

private boolean mIsRefreshDuring;

/**

* 可以进下拉刷新

*/

private boolean mCanDownPull;

/**

* 可以进行上拉刷新

*/

private boolean mCanUpPull;

/**

* 判断触摸后是否是初次移动

*/

private boolean mIsFirstMove;

/**

* y轴呢平移的距离

*/

private int mDistanceY;

/**

* 刷新接口对象

*/

private OnRefresh mOnRefresh;

/**

* 用于控制事件拦截的变量

*/

private boolean mCanIntercept;

private int mTouchSlop;

private int mDistance;

private LayoutParams mHeaderParams;

private View mHeaderView;

private View mFootView;

private int mHeaderMaxHeight;

private int mStartY;

private LayoutParams mFootParams;

private int mFootMaxHeight;

private PullCallBack mCallBack;

private View mChildView;

private ObjectAnimator mAnimator;

public RefreshLayout(Context context) {

super(context);

initData();

}

public RefreshLayout(Context context, AttributeSet attrs) {

super(context, attrs);

initData();

}

public RefreshLayout(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

initData();

}

/**

* 必须让头尾控件实现的接口

*/

public interface HeadAndFootCallBack {

//设置属性

void setAttribute();

//开始刷新

void startPull();

//停止刷新

void stopPull();

}

/**

* 必须让被拖动的控件子类实现

*/

public interface PullCallBack {

boolean canDownPull();

boolean canUpPull();

}

private void initData() {

//不调用该方法不能进行绘制

setWillNotDraw(false);

}

/**

* 下拉刷新完成后必须使用该方法

*/

public void downPullFinish() {

mAnimator.setFloatValues(mChildView.getTranslationY(), 0);

mAnimator.start();

((HeadAndFootCallBack) mHeaderView).stopPull();

}

/**

* 上拉完成后必须调用该方法

*/

public void upPullFinish() {

mAnimator.setFloatValues(mChildView.getTranslationY(), 0);

mAnimator.start();

((HeadAndFootCallBack) mFootView).stopPull();

}

/**

* 自动下拉刷新

*/

public void autoDownPullForHead() {

postDelayed(new Runnable() {

@Override

public void run() {

mCanDownPull = true;

mCanUpPull = false;

mAnimator.setFloatValues(10, mHeaderMaxHeight);

mAnimator.start();

((HeadAndFootCallBack) mHeaderView).startPull();

mOnRefresh.onDownPullRefresh();

}

}, 500);

}

/**

* 自动下拉刷新

*/

public void autoUpPullForHead() {

postDelayed(new Runnable() {

@Override

public void run() {

mCanDownPull = false;

mCanUpPull = true;

mAnimator.setFloatValues(0, mFootMaxHeight);

mAnimator.start();

((HeadAndFootCallBack) mFootView).startPull();

mOnRefresh.onUpPullRefresh();

}

}, 500);

}

@Override

public boolean onInterceptTouchEvent(MotionEvent ev) {

return mCanIntercept;

}

@Override

public boolean onTouchEvent(MotionEvent event) {

return true;

}

@Override

public boolean dispatchTouchEvent(MotionEvent event) {

Log.e("shen", "mIsRefreshDuring=" + mIsRefreshDuring);

if (mIsRefreshDuring)

/**如果正在进行刷新将不会获取MotionEvent*/

{

return super.dispatchTouchEvent(event);

}

switch (event.getAction()) {

case MotionEvent.ACTION_DOWN:

mStartY = (int) event.getY();

initPull();

break;

case MotionEvent.ACTION_MOVE:

if (event.getPointerCount() == 1) {

int moveY = (int) event.getY();

mDistanceY = (moveY - mStartY) / V_REFRESH;

if (!mIsFirstMove && mDistanceY != 0 && mDistanceY < mTouchSlop) {

mCanDownPull = mDistanceY > 0;

mCanUpPull = !mCanDownPull;

mIsFirstMove = true;

}

if (mCanDownPull && mCallBack.canDownPull()) {

upDataForDownPull();//下拉刷新

mChildView.setEnabled(false);

mCanIntercept = true;

}

if (mCanUpPull && mCallBack.canUpPull()) {

upDataForUpPull();//上拉加载

mChildView.setEnabled(false);

mCanIntercept = true;

}

mStartY = moveY;

}

break;

case MotionEvent.ACTION_UP:

mIsRefreshDuring = true;

mIsFirstMove = false;

if (mHeaderParams.height >= mHeaderMaxHeight)

/**可以下拉刷新**/

{

((HeadAndFootCallBack) mHeaderView).startPull();

mOnRefresh.onDownPullRefresh();

} else if (mFootParams.height >= mFootMaxHeight)

/**可以上拉刷新**/

{

((HeadAndFootCallBack) mFootView).startPull();

mOnRefresh.onUpPullRefresh();

} else if (mHeaderParams.height > 0 && mHeaderParams.height < mHeaderMaxHeight)

/**不能进行下拉刷新，收回**/

{

releaseForDownFinished();

} else if (mFootParams.height > 0 && mFootParams.height < mFootMaxHeight)

/**不能进行下拉刷新，收回**/

{

releaseForUpFinished();

} else {

mIsRefreshDuring = false;

mCanIntercept = false;

}

break;

}

super.dispatchTouchEvent(event);

return true;

}

/**

* 每次进行触摸都需要进行初始化

*/

private void initPull() {

mCanDownPull = false;

mCanUpPull = false;

}

/**

* 不需要进行上拉刷新

*/

private void releaseForUpFinished() {

mAnimator.setFloatValues(mChildView.getTranslationY(), 0);

mAnimator.start();

}

/**

* 不需要进行下拉刷新

*/

private void releaseForDownFinished() {

mAnimator.setFloatValues(mChildView.getTranslationY(), 0);

mAnimator.start();

}

/**

* 上拉时处理手势

*/

private void upDataForUpPull() {

if (mDistanceY != 0) {

mFootParams.height -= mDistanceY;

if (mFootParams.height <= 0) {

mFootParams.height = 0;

}

if (mFootParams.height >= mFootMaxHeight) {

mFootParams.height = mFootMaxHeight;

}

mChildView.setTranslationY(-mFootParams.height);

mFootView.requestLayout();

}

}

/**

* 下拉时处理手势

*/

private void upDataForDownPull() {

if (mDistanceY != 0) {

mHeaderParams.height += mDistanceY;

if (mHeaderParams.height >= mHeaderMaxHeight) { //最大

mHeaderParams.height = mHeaderMaxHeight;

}

if (mHeaderParams.height <= 0) { //最小

mHeaderParams.height = 0;

}

mChildView.setTranslationY(mHeaderParams.height);

mHeaderView.requestLayout();

}

}

@Override

protected void onAttachedToWindow() {

super.onAttachedToWindow();

}

@Override

protected void onFinishInflate() {

super.onFinishInflate();

//加载头

mHeaderView = getChildAt(0);

if (!(mHeaderView instanceof HeadAndFootCallBack)) {

new IllegalStateException("HeaderView必须实现HeadAndFootCallBack接口");

}

((HeadAndFootCallBack) mHeaderView).setAttribute();

mHeaderParams = (LayoutParams) mHeaderView.getLayoutParams();

mHeaderParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);

//加载尾

mFootView = getChildAt(2);

if (!(mFootView instanceof HeadAndFootCallBack)) {

new IllegalStateException("FootView必须实现HeadAndFootCallBack接口");

}

((HeadAndFootCallBack) mFootView).setAttribute();

mFootParams = (LayoutParams) mFootView.getLayoutParams();

mFootParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);

mChildView = getChildAt(1);

if (!(mChildView instanceof HeadAndFootCallBack)) {

new IllegalStateException("ChildView必须实现PullCallBack接口");

}

mCallBack = (PullCallBack) getChildAt(1);

//设置动画

mAnimator = ObjectAnimator.ofFloat(mChildView, "translationY", 0);

mAnimator.setInterpolator(new DecelerateInterpolator());

mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

int translationY = (int) mChildView.getTranslationY();

if (mCanUpPull) { //从移动到的位置往下滑

mFootParams.height = Math.abs(translationY);

mFootView.requestLayout();

} else if (mCanDownPull) {

mHeaderParams.height = Math.abs(translationY);

mHeaderView.requestLayout();

}

Log.e("shen", "translationY=" + translationY);

Log.e("shen", "mHeaderParams.height=" + mHeaderParams.height);

if (translationY == 0) {

mChildView.setEnabled(true);

mDistanceY = 0; //重置

mIsRefreshDuring = false; //重置

mCanIntercept = false;

} else {

mIsRefreshDuring = true;

}

}

});

}

@Override

protected void onSizeChanged(int w, int h, int oldw, int oldh) {

super.onSizeChanged(w, h, oldw, oldh);

mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();

mDistance = mTouchSlop * 5;

//设置下拉头初始属性

mHeaderMaxHeight = mHeaderParams.height;

mHeaderParams.height = 0;

mHeaderView.requestLayout();

//设置上拉尾初始属性

mFootMaxHeight = mFootParams.height;

mFootParams.height = 0;

mFootView.requestLayout();

}

/**

* 下拉/上拉事件监听

*/

public interface OnRefresh {

/**

* 下拉刷新

*/

void onDownPullRefresh();

/**

* 上拉加载

*/

void onUpPullRefresh();

}

public void setOnRefresh(OnRefresh onRefresh) {

mOnRefresh = onRefresh;

}

}

给他添加三个控件，头尾就是刷新头、尾，第二个就是正常显示的控件。必须让头尾实现HeadAndFootCallBack接口，来设置属性，通知开始刷新、结束刷新

难点： 现在来说下开发时遇到的难点

由于判断在dispatchTouchEvent中，导致如果该控件以及子控件都不消费该事件的话，就会造成事件不会发送到它，因为如果不消费DOWN事件的话，之后所有的事件都不会在进行接收。解决方式，让该控件onTouchEvent方法消返回true，当子控件不进行事件消费的话，就会返回由该控件消费，不会造成因DOWN事件不消费而无法接收到事件，导致dispatchTouchEvent也不消费事件

动画，动画就是我的伤痛，最近在学习估值器

这个控件自认为写的不错，通过他可以帮我们学习事件分发、动画、接口回调，也是有一定的学习意义

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。