前言
又到了新的一月,今天提供一个Android自定义底部上拉布局的实现,起因是自己在项目中需要实现这样一个控件,干脆自己写一个练练手。
写完了觉得能想到的需求都基本有了(可能会有其它需求,不过基本上改吧改吧就行了),又花了一点时间直接放到了Github上托管,希望能给您一些参考价值:
SlideBottomLayout-Android 简单易上手的Android底部上拉控件
先看一下实现效果:
分析一下这种控件的基本需求有以下几种:
1.有一个部分是能够作为把手(就是图中的handle,)进行拖拽的,这部分高度是暴露在界面中的 -> 需要实现:Handle按钮
* 特殊需求特殊分析,比如让这个Handle透明实现无Handle的效果
2.底部上啦布局是有一定高度限制的,不一定覆盖设备的整个屏幕 -> 需要自定义最大高度
3.当从底部上拉一点点时抬手,布局缩回,若超过一定高度,自动弹到最高,隐藏同理 -> 需要自定义自动到达顶部/隐藏的阈值
直接使用
直接使用也很简单,笔者进行了简单的封装,以供参考:
1. 在Project的build.gradle文件中添加:
allprojects { repositories { ... maven { url 'https://jitpack.io' } } }
2.在Module的build.gradle文件中添加:
dependencies { compile 'com.github.qingmei2:SlideBottomLayout-Android:1.2.3' }
3.Add view in your layout:
需要注意的是:为了简单实现,笔者偷了个懒,设定为该布局下只能有一个直接的子View(类似ScrollView)
因此如果您添加需要一个布局,请在外面嵌套一个ViewGroup:
<com.qingmei2.library.SlideBottomLayout android:id="@+id/slideLayout" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_marginTop="200dp" app:handler_height="50dp"> <!--app:handler_height:该属性就是您要暴露出来Handle的高度,详见下方的TextView(id=handle)--> <!--Just one child--> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <TextView android:id="@+id/handle" android:layout_width="match_parent" android:layout_height="50dp" android:background="#d95858" android:gravity="center" android:text="handle" android:textColor="@android:color/white" android:textSize="16sp" /> <android.support.v7.widget.RecyclerView android:id="@+id/recycler_view" android:layout_width="match_parent" android:layout_height="wrap_content"> </android.support.v7.widget.RecyclerView> </LinearLayout> </com.qingmei2.library.SlideBottomLayout>
实现步骤
具体代码如下,其中上述需求的设置方式都已经在代码中声明:
先看下属性声明:
<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="SlideBottomLayout"> <attr name="handler_height" format="dimension"></attr> </declare-styleable> </resources>
public class SlideBottomLayout extends LinearLayout { public void setShortSlideListener(ShortSlideListener listener) { this.shortSlideListener = listener; } private ShortSlideListener shortSlideListener; /** * The {@link MotionEvent#ACTION_DOWN} gesture location. */ private int downY; /** * The {@link MotionEvent#ACTION_MOVE} gesture location. */ private int moveY; /** * the value of moved distance by the gesture. When the value was modified and not exceed * the {@link #movedMaxDis}, then make this ViewGroup move. */ private int movedDis; /** * The max distance that the {@link SlideBottomLayout} can scroll to, it used to compare with the * {@link #downY}, determine whether it can slide by the gesture. */ private int movedMaxDis; /** * ChildView of the {@link SlideBottomLayout}, you can set a Layout such as the {@link LinearLayout}、 * {@link android.widget.RelativeLayout} ect. * We set the rules that {@link SlideBottomLayout} just can have one child-view, or else get a * {@link RuntimeException} at {@link #onFinishInflate()} */ private View childView; /** * The control {@link SlideBottomLayout} automatically switches the threshold of the state. if * this ViewGroup moved distance more than {@link #movedMaxDis} * it, switch the state of * {@link #arriveTop} right now. * </p> * See the {@link #touchActionUp(float)}. */ private float hideWeight = 0.25f; //3.注意,这个接口用来设置「需要自定义自动到达顶部/隐藏的阈值」 public void setHideWeight(float hideWeight) { if (hideWeight <= 0 || hideWeight > 1) throw new IllegalArgumentException("hideWeight should belong (0f,1f]"); this.hideWeight = hideWeight; } private Scroller mScroller; /** * It means the {@link #childView} is arriving the top of parent or else. */ private boolean arriveTop = false; /** * the {@link #childView} Initially visible height */ private float visibilityHeight; //1.初始化Handle显示高度,建议您在xml中设置对应属性来实现该效果 public void setVisibilityHeight(float visibilityHeight) { this.visibilityHeight = visibilityHeight; } public SlideBottomLayout(@NonNull Context context) { super(context); } public SlideBottomLayout(@NonNull Context context, @Nullable AttributeSet attrs) { super(context, attrs); initAttrs(context, attrs); } public SlideBottomLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initAttrs(context, attrs); } /** * Get the config from {@link R.styleable}, then init other configrations{@link #initConfig(Context)}. * * @param context the {@link Context} * @param attrs the configs in layout attrs. */ private void initAttrs(Context context, AttributeSet attrs) { final TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.SlideBottomLayout); visibilityHeight = ta.getDimension(R.styleable.SlideBottomLayout_handler_height, 0); ta.recycle(); initConfig(context); } private void initConfig(Context context) { if (mScroller == null) mScroller = new Scroller(context); this.setBackgroundColor(Color.TRANSPARENT); } /** * It start a judgement for ensure the child-view be unique in this method,then assgin it * to {{@link #childView}. * this method will be called before the {@link #onMeasure(int, int)} */ @Override protected void onFinishInflate() { super.onFinishInflate(); if (getChildCount() == 0 || getChildAt(0) == null) { throw new RuntimeException("there have no child-View in the SlideBottomLayout!"); } if (getChildCount() > 1) { throw new RuntimeException("there just alow one child-View in the SlideBottomLayout!"); } childView = getChildAt(0); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); movedMaxDis = (int) (childView.getMeasuredHeight() - visibilityHeight); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { super.onLayout(changed, l, t, r, b); childView.layout(0, movedMaxDis, childView.getMeasuredWidth(), childView.getMeasuredHeight() + movedMaxDis); } @Override public boolean onTouchEvent(MotionEvent event) { final float dy = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: if (touchActionDown(dy)) return true; break; case MotionEvent.ACTION_MOVE: if (touchActionMove(dy)) return true; break; case MotionEvent.ACTION_UP: if (touchActionUp(dy)) return true; break; } return super.onTouchEvent(event); } @Override public void computeScroll() { super.computeScroll(); if (mScroller == null) mScroller = new Scroller(getContext()); if (mScroller.computeScrollOffset()) { scrollTo(0, mScroller.getCurrY()); postInvalidate(); } } /** * When the touch event is {@link MotionEvent#ACTION_UP}, * then judge the state of view group and control the {@link Scroller} to scroll. * <p> * In this ViewGroup, we set the rules that is if this scroll gesture's move distance * more than {@link #movedMaxDis} * {@link #hideWeight}(default hideWeight value is 1/4 heights * of this ViewGroup), then call {@link #hide()} or {@link #show()} right now. which method will * be call depends on {@link #arriveTop}. * <p * if the scroll gesture's move distance don't reach the goal value, then call the * {@link ShortSlideListener#onShortSlide(float)} if you call {@link #setShortSlideListener(ShortSlideListener)} * init this ViewGroup. else will call {@link #hide()}. * * @param eventY The location of trigger * @return Be used to determine consume this event or else. */ public boolean touchActionUp(float eventY) { if (movedDis > movedMaxDis * hideWeight) { switchVisible(); } else { if (shortSlideListener != null) { shortSlideListener.onShortSlide(eventY); } else { hide(); } } return true; } /** * When the touch event is {@link MotionEvent#ACTION_MOVE}, * then judge the state of view group and control the {@link Scroller} to scroll. * <p> * In this ViewGroup, we set the rules that is if this scroll gesture's move distance * more than {@link #movedMaxDis} * {@link #hideWeight}(default hideWeight value is 1/4 heights of this ViewGroup), * then call {@link #hide()} or {@link #show()} right now. * <p> * * @param eventY The location of trigger * @return Be used to determine consume this event or else. */ public boolean touchActionMove(float eventY) { moveY = (int) eventY; //the dy is sum of the move distance, the value > 0 means scroll up, the value < 0 means scroll down. final int dy = downY - moveY; if (dy > 0) { //scroll up movedDis += dy; if (movedDis > movedMaxDis) movedDis = movedMaxDis; if (movedDis < movedMaxDis) { scrollBy(0, dy); downY = moveY; return true; } } else { //scroll down movedDis += dy; if (movedDis < 0) movedDis = 0; if (movedDis > 0) { scrollBy(0, dy); } downY = moveY; return true; } return false; } /** * When the touch event is {@link MotionEvent#ACTION_DOWN}, * Record the location of this action. * * @param eventY The location of trigger * @return Be used to determine consume this event or else. */ public boolean touchActionDown(float eventY) { downY = (int) eventY; //Whether custom this gesture. if (!arriveTop && downY < movedMaxDis) { return false; } else return true; } /** * the extand method for showing {@link SlideBottomLayout} */ public void show() { scroll2TopImmediate(); } /** * the extand method for hiding {@link SlideBottomLayout} */ public void hide() { scroll2BottomImmediate(); } /** * @return The ViewGroup is arrive top or else. */ public boolean switchVisible() { if (arriveTop()) hide(); else show(); return arriveTop(); } public boolean arriveTop() { return this.arriveTop; } public void scroll2TopImmediate() { mScroller.startScroll(0, getScrollY(), 0, (movedMaxDis - getScrollY())); invalidate(); movedDis = movedMaxDis; arriveTop = true; } public void scroll2BottomImmediate() { mScroller.startScroll(0, getScrollY(), 0, -getScrollY()); postInvalidate(); movedDis = 0; arriveTop = false; } }
注释也比较明了,如果有疑问,详细请参照SlideBottomLayout-Android 简单易上手的Android底部上拉控件
里面有相对详细的使用说明,此外,如果还有一些需求,您可以在issue中提出,提前感谢!
以上这篇Android 自定义底部上拉控件的实现方法就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持小牛知识库。
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