關(guān)鍵字：Behavior锹雏、材料設(shè)計(jì)
項(xiàng)目地址：AboutMaterialDesign
大多數(shù)情況下轻绞，我們的項(xiàng)目只需要用到材料設(shè)計(jì)的 Toolbar DrawerLayout TabLayout 等等現(xiàn)成的控件就可以了奸远，使用方便芍瑞，也允許我們有不同程度的自定義優(yōu)化。但是一旦業(yè)務(wù)對于界面的交互有更明確的要求屑那，上面的控件就變得不再那么夠用益眉。材料設(shè)計(jì)為我們提供了協(xié)調(diào)者布局 CoordinatorLayout 用于聯(lián)系所有子控件姥份，使得子控件之間在保持相對獨(dú)立的同時(shí)郭脂，又能相互影響，適時(shí)變化澈歉。
而這一切除了要感謝 CoordinatorLayout 的出現(xiàn)展鸡，還要記得 Google 工程師在 Behavior 上的付出。
學(xué)習(xí) Behavior 就是學(xué)習(xí)一點(diǎn)：根據(jù)監(jiān)聽得到合適的時(shí)機(jī)去修改目標(biāo)視圖的狀態(tài)埃难。
帶著這樣的學(xué)習(xí)目的莹弊，我們?nèi)ゲ榭聪嚓P(guān)代碼涤久，會容易很多。
根據(jù)文檔箱硕，我們可以知道拴竹，Behavior 是 CoordinatorLayout 的一個(gè)內(nèi)部類。
Interaction behavior plugin for child views of {@link CoordinatorLayout}.
A Behavior implements one or more interactions that a user can take on a child view.
These interactions may include drags, swipes, flings, or any other gestures.
一剧罩、使用自帶的 Behavior
由于大會影響栓拜，翻不了墻，因此只揀了我記得的 BottomSheetBehavior 和 SwipeDismissBehavior 來寫惠昔。
1) BottomSheetBehavior
GIF.gif
BottomSheetBehavior 一共有五個(gè)狀態(tài)幕与，上面的效果為 BottomSheetBehavior 對應(yīng)的三個(gè)狀態(tài)：
/**
* The bottom sheet is dragging.
*/
public static final int STATE_DRAGGING = 1;
/**
* The bottom sheet is settling.
*/
public static final int STATE_SETTLING = 2;
/**
* The bottom sheet is expanded.
*/
public static final int STATE_EXPANDED = 3;
/**
* The bottom sheet is collapsed.
*/
public static final int STATE_COLLAPSED = 4;
/**
* The bottom sheet is hidden.
*/
public static final int STATE_HIDDEN = 5;
實(shí)現(xiàn)上面的效果很簡單，只需要在以 CoordinatorLayout 為根節(jié)點(diǎn)的布局文件中增加一個(gè)容器放置彈框的內(nèi)容镇防，然后在容器根節(jié)點(diǎn)下新增屬性：
app:behavior_hideable="true"
app:behavior_peekHeight="100dp"
app:layout_behavior="@string/bottom_sheet_behavior"
其中
- layout_behavior 用于指定容器指定的 Behavior 啦鸣，在使用自定義 Behavior 的時(shí)候，也可以通過這個(gè)方法来氧，將視圖和 Behavior 關(guān)聯(lián)
- behavior_peekHeight 用于指定視圖折疊時(shí)顯示的高度
- behavior_hideable 用于指定視圖是否可以完全隱藏
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/cl"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
>
<android.support.v4.widget.NestedScrollView
android:id="@+id/bottom_sheet"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:behavior_hideable="true"
app:behavior_peekHeight="50dp"
app:layout_behavior="@string/bottom_sheet_behavior"
>
<!-- NestedScrollView里設(shè)置你的底部表長什么樣的-->
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
代碼中需要注意這樣幾個(gè)方法：
//1.動(dòng)態(tài)設(shè)置 Behavior
BottomSheetBehavior behavior = new BottomSheetBehavior();
behavior.setPeekHeight(100);
behavior.setHideable(true);
behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
@Override
public void onStateChanged(@NonNull View bottomSheet, int newState) {
//狀態(tài)變化時(shí)調(diào)用
}
@Override
public void onSlide(@NonNull View bottomSheet, float slideOffset) {
//滑動(dòng)時(shí)調(diào)用诫给，可以根據(jù) slideOffset 配置動(dòng)畫效果
}
});
//2.獲取 xml 中設(shè)置的 behavior 并設(shè)置相關(guān)屬性
View bottomSheet = findViewById(R.id.bottom_sheet);
if (bottomSheet != null) {
behavior = BottomSheetBehavior.from(bottomSheet);
behavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
}
//3.獲取當(dāng)前狀態(tài)
int state = behavior.getState();
2) SwipeDismissBehavior
在 xml 布局文件中，利用聯(lián)想并沒有跳出這個(gè) Behavior啦扬。但是在 Java 代碼中中狂，我們還是可以找到這個(gè)類的。
SwipeDismissBehavior<View> behavior = new SwipeDismissBehavior<>();
behavior.setSwipeDirection(SWIPE_DIRECTION_START_TO_END);
//behavior.setDragDismissDistance(0.5f);//
//behavior.setStartAlphaSwipeDistance(0.1f);//設(shè)置拖動(dòng)的有效距離扑毡，即開始透明消失的距離
//behavior.setEndAlphaSwipeDistance(0.7f);//完全消失時(shí)候的距離
//behavior.setSensitivity(0.5f);//敏感度
behavior.setListener(new SwipeDismissBehavior.OnDismissListener() {
@Override
public void onDismiss(View view) {
Log.d(TAG, "onDismiss: ");
}
@Override
public void onDragStateChanged(int state) {
Log.d(TAG, "onDragStateChanged: ");
}
});
((CoordinatorLayout.LayoutParams) mTextView.getLayoutParams()).setBehavior(behavior);
GIF.gif
二胃榕、自定義簡單 Behavior
下面貼出大部分可重寫方法的代碼：
public class TestBehavior extends CoordinatorLayout.Behavior<View> {
private static final String TAG = "TestBehavior";
public TestBehavior() {
super();
Log.i(TAG, "TestBehavior(1): ");
}
public TestBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
Log.i(TAG, "TestBehavior(2): ");
}
//--------------------[布局事件 start]-----------------------------------------------
@Override
public void onAttachedToLayoutParams(@NonNull CoordinatorLayout.LayoutParams params) {
super.onAttachedToLayoutParams(params);
Log.i(TAG, "onAttachedToLayoutParams: ");
}
@Override
public void onDetachedFromLayoutParams() {
super.onDetachedFromLayoutParams();
Log.i(TAG, "onDetachedFromLayoutParams: ");
}
@Override
public boolean onMeasureChild(CoordinatorLayout parent, View child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed) {
Log.i(TAG, "onMeasureChild: ");
return super.onMeasureChild(parent, child, parentWidthMeasureSpec, widthUsed, parentHeightMeasureSpec, heightUsed);
}
@Override
public boolean onLayoutChild(CoordinatorLayout parent, View child, int layoutDirection) {
Log.i(TAG, "onLayoutChild: ");
return super.onLayoutChild(parent, child, layoutDirection);
}
//--------------------[布局事件 end]-----------------------------------------------
//--------------------[觸摸事件 start]-----------------------------------------------
@Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, View child, MotionEvent ev) {
Log.i(TAG, "onInterceptTouchEvent: ");
return super.onInterceptTouchEvent(parent, child, ev);
}
@Override
public boolean onTouchEvent(CoordinatorLayout parent, View child, MotionEvent ev) {
Log.i(TAG, "onTouchEvent: ");
return super.onTouchEvent(parent, child, ev);
}
//--------------------[觸摸事件 end]-----------------------------------------------
//--------------------[狀態(tài)改變事件 start]-----------------------------------------------
@Override
public int getScrimColor(CoordinatorLayout parent, View child) {
Log.i(TAG, "getScrimColor: ");
return super.getScrimColor(parent, child);
}
@Override
public float getScrimOpacity(CoordinatorLayout parent, View child) {
Log.i(TAG, "getScrimOpacity: ");
return super.getScrimOpacity(parent, child);
}
@Override
public boolean blocksInteractionBelow(CoordinatorLayout parent, View child) {
Log.i(TAG, "blocksInteractionBelow: ");
return super.blocksInteractionBelow(parent, child);
}
@Override
public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
Log.i(TAG, "layoutDependsOn: dependency=="+dependency.getClass().getSimpleName());
return super.layoutDependsOn(parent, child, dependency);
}
@Override
public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
Log.i(TAG, "onDependentViewChanged: dependency=="+dependency.getClass().getSimpleName());
return super.onDependentViewChanged(parent, child, dependency);
}
@Override
public void onDependentViewRemoved(CoordinatorLayout parent, View child, View dependency) {
Log.i(TAG, "onDependentViewRemoved: dependency=="+dependency.getClass().getSimpleName());
super.onDependentViewRemoved(parent, child, dependency);
}
//--------------------[狀態(tài)改變事件 end]-----------------------------------------------
//--------------------[滑動(dòng)事件 start]-----------------------------------------------
@Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
Log.i(TAG, "onStartNestedScroll: ");
return super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
@Override
public void onNestedScrollAccepted(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
Log.i(TAG, "onNestedScrollAccepted: ");
super.onNestedScrollAccepted(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
@Override
public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, View child, View target) {
Log.i(TAG, "onStopNestedScroll: ");
super.onStopNestedScroll(coordinatorLayout, child, target);
}
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
Log.i(TAG, "onNestedScroll: ");
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
}
@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dx, int dy, int[] consumed) {
Log.i(TAG, "onNestedPreScroll: ");
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
}
@Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, View child, View target, float velocityX, float velocityY, boolean consumed) {
Log.i(TAG, "onNestedFling: ");
return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}
@Override
public boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, View child, View target, float velocityX, float velocityY) {
Log.i(TAG, "onNestedPreFling: ");
return super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY);
}
//--------------------[滑動(dòng)事件 end]-----------------------------------------------
}
而我們的需求通常集中在這幾個(gè)方法中：
//監(jiān)聽狀態(tài)的改變 返回是否調(diào)用 onDependentViewChanged 方法
@Override
public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
Log.i(TAG, "layoutDependsOn: dependency=="+dependency.getClass().getSimpleName());
return super.layoutDependsOn(parent, child, dependency);
}
//監(jiān)聽狀態(tài)的改變 反饋方法
@Override
public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
Log.i(TAG, "onDependentViewChanged: dependency=="+dependency.getClass().getSimpleName());
return super.onDependentViewChanged(parent, child, dependency);
}
//監(jiān)聽滑動(dòng)，返回 true 時(shí)調(diào)用 onNestedScroll 等一系列方法
@Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View directTargetChild,
View target, int nestedScrollAxes) {
return super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
/**
* 正在滾動(dòng) 反饋方法
*
* 這里我們只關(guān)心y軸方向的滑動(dòng)瞄摊，所以簡單測試了dyConsumed勋又、dyUnconsumed
* dyConsumed > 0 && dyUnconsumed == 0 上滑中
* dyConsumed == 0 && dyUnconsumed > 0 到邊界了還在上滑
*
* dyConsumed < 0 && dyUnconsumed == 0 下滑中
* dyConsumed == 0 && dyUnconsumed < 0 到邊界了還在下滑
*
* @param coordinatorLayout parent
* @param child child
* @param target dependency
* @param dxConsumed x軸滑動(dòng)的距離
* @param dyConsumed y軸滑動(dòng)的距離
* @param dxUnconsumed 到頂之后滑動(dòng)的距離
* @param dyUnconsumed 到頂之后滑動(dòng)的距離
*/
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
Log.i(TAG, String.format("onNestedScroll: dxConsumed==%d,dyConsumed==%d,dxUnConsumed==%d,dyUnConsumed==%d", dxConsumed,dyConsumed,dxUnconsumed,dyUnconsumed));
}
實(shí)現(xiàn)效果：視圖 child 隨 dependency 的改變而改變
GIF.gif
這個(gè)效果是拖拽 dependency 的時(shí)候，目標(biāo)視圖會按照預(yù)設(shè)的規(guī)則變化位置换帜。
思路：
- 自定義一個(gè) Behavior 重寫 layoutDependsOn 和 onDependentViewChanged 方法
- 在 layoutDependsOn 中楔壤，判斷該 dependency 是否為我們指定的視圖
- 在 onDependentViewChanged 設(shè)置目標(biāo)視圖的改變規(guī)則
下面貼上測試 Behavior 代碼:
public class TestDragBehavior extends CoordinatorLayout.Behavior<View> {
private static final String TAG = "TestDragBehavior";
private int width;
private int height;
/**
* 這個(gè)構(gòu)造方法必須重載，因?yàn)樵贑oordinatorLayout里利用反射去獲取Behavior的時(shí)候就是拿的這個(gè)構(gòu)造
*/
public TestDragBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
width = context.getResources().getDisplayMetrics().widthPixels;
height = context.getResources().getDisplayMetrics().heightPixels;
}
/**
* 是否調(diào)用 onDependentViewChanged
* @param parent 父容器
* @param child 子視圖
* @param dependency 依賴視圖
* @return 是否依賴
*/
@Override
public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
return dependency instanceof DragText;
}
/**
* 在這里我們定義 child 要執(zhí)行的具體動(dòng)作
* @return child是否要執(zhí)行相應(yīng)動(dòng)作
*/
@Override
public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
int top = dependency.getTop();
int left = dependency.getLeft();
int x = width - left - child.getWidth();
int y = height - top - child.getHeight();
setPosition(child, x, y);
return true;
}
private void setPosition(View child, int x, int y) {
CoordinatorLayout.MarginLayoutParams layoutParams = (CoordinatorLayout.MarginLayoutParams) child.getLayoutParams();
layoutParams.leftMargin = x;
layoutParams.topMargin = y;
child.setLayoutParams(layoutParams);
}
}
實(shí)現(xiàn)效果：視圖 child 隨 dependency 滾動(dòng)狀態(tài)的改變而改變
GIF.gif
下面貼上測試 Behavior 代碼:
public class TestScrollBehavior extends CoordinatorLayout.Behavior<FloatingActionButton> {
private static final String TAG = "TestScrollBehavior";
public TestScrollBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
/**
* 監(jiān)聽滾動(dòng)惯驼，返回是否調(diào)用 onNestedScroll 等監(jiān)聽代碼
* @param coordinatorLayout
* @param child
* @param directTargetChild
* @param target
* @param nestedScrollAxes
* @return
*/
@Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View directTargetChild,
View target, int nestedScrollAxes) {
return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
}
/**
* 正在滾動(dòng)
*
* 這里我們只關(guān)心y軸方向的滑動(dòng)蹲嚣，所以簡單測試了dyConsumed、dyUnconsumed
* dyConsumed > 0 && dyUnconsumed == 0 上滑中
* dyConsumed == 0 && dyUnconsumed > 0 到邊界了還在上滑
*
* dyConsumed < 0 && dyUnconsumed == 0 下滑中
* dyConsumed == 0 && dyUnconsumed < 0 到邊界了還在下滑
*
* @param coordinatorLayout parent
* @param child child
* @param target dependency
* @param dxConsumed x軸滑動(dòng)的距離
* @param dyConsumed y軸滑動(dòng)的距離
* @param dxUnconsumed 到頂之后滑動(dòng)的距離
* @param dyUnconsumed 到頂之后滑動(dòng)的距離
*/
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
Log.i(TAG, String.format("onNestedScroll: dxConsumed==%d,dyConsumed==%d,dxUnConsumed==%d,dyUnConsumed==%d", dxConsumed,dyConsumed,dxUnconsumed,dyUnconsumed));
if (((dyConsumed > 0 && dyUnconsumed == 0)
|| (dyConsumed == 0 && dyUnconsumed > 0))
&& child.getVisibility() != View.INVISIBLE) {// 上滑隱藏
child.setVisibility(View.INVISIBLE);
} else if (((dyConsumed < 0 && dyUnconsumed == 0)
|| (dyConsumed == 0 && dyUnconsumed < 0))
&& child.getVisibility() != View.VISIBLE ) {//下滑顯示
child.setVisibility(View.VISIBLE);
}
}
}
實(shí)現(xiàn)效果：滑動(dòng)改變 top 布局位置
GIF.gif
/**
* Created by Arno on 2017/10/24.
*
* 實(shí)現(xiàn)上滑滾出跳座，下滑跟進(jìn)的效果
*/
public class TestScrollBehavior2 extends CoordinatorLayout.Behavior<View>{
private static final String TAG = "TestScrollBehavior2";
private int offset = 0;
/**
* 必須重寫這個(gè)方法
* @param context
* @param attrs
*/
public TestScrollBehavior2(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
}
@Override
public boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, View child, View target, float velocityX, float velocityY) {
return true;
}
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
int temp = offset;
int top = offset - dyConsumed;
//上滑
if (dyConsumed > 0) {
temp = Math.max(top,-child.getHeight());
}
//下滑
if (dyConsumed < 0) {
temp = Math.min(top,0);
}
child.offsetTopAndBottom(temp - offset);
offset = temp;
}
}
注意：
上面大部分的點(diǎn)端铛，需要自行測試泣矛，這里放上代碼中獲取 Behavior 的方法（還找了一小會它藏哪里去了）疲眷，根據(jù)源碼可以看到，Behavior 被存儲在 CoordinatorLayout.LayoutParams 中您朽。
CoordinatorLayout.Behavior behavior = ((CoordinatorLayout.LayoutParams) bottomSheet.getLayoutParams()).getBehavior();
以上狂丝，謝謝觀賞
