android RecyclerView 添加动画 recyclerview item动画

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mob64ca1412b28c 2023-09-22 21:00:54

文章标签 动画 android ide xml 文章分类 Android 移动开发

自动Material Design出现以来，我对一些视频中演示的网格铺开动画感到惊讶。这是一种斜对角线动画，让activity从上到下从左到右铺开。非常漂亮。

android RecyclerView 添加动画 recyclerview item动画_android

我一直试图尝试所有能得到那种效果的方法。一种办法是，使用RecyclerView::notifyItemInserted()方法，这是很多人都提到的办法。但是这个方法没有提供太多控制动画顺序的方法，因此看起来并不是一个好办法。另一个就是在onBind()中必要的时候对每个元素使用动画，这也的确可行。但是那样的话代码就比较脆弱和过于侵入性（我们是在adapter中添加的动画）。要让它恰当的工作比较困难。

布局动画

最后，解决的办法居然比想象的简单。我得承认我很少用布局动画（layout animation），因此我没能立即想到这个办法。但是在寻找答案的过程中，我发现了这个非常棒的代码： gist from Musenkishi

，它给我指明了解决方法。这里的问题是RecyclerView默认并没有使用 layout animation，但是这个代码可以让它能像GridView那样使用GridLayoutAnimation。我们提到的gist是这样的：

1. /*
2.  * Copyright (C) 2014 Freddie (Musenkishi) Lust-Hed
3.  *
4.  * Licensed under the Apache License, Version 2.0 (the “License”);
5.  * you may not use this file except in compliance with the License.
6.  * You may obtain a copy of the License at
7.  *
8.  *      http://www.apache.org/licenses/LICENSE-2.0
9.  *
10.  * Unless required by applicable law or agreed to in writing, software
11.  * distributed under the License is distributed on an “AS IS” BASIS,
12.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13.  * See the License for the specific language governing permissions and
14.  * limitations under the License.
15.  */
16.    
17. package
18.   
19. import
20. import
21. import
22. import
23. import
24. import
25. import
26.   
27. /**
28.  * An extension of RecyclerView, focused more on resembling a GridView.
29.  * Unlike {@link android.support.v7.widget.RecyclerView}, this view can handle
30.  * {@code <gridLayoutAnimation>} as long as you provide it a
31.  * {@link android.support.v7.widget.GridLayoutManager} in
32.  * {@code setLayoutManager(LayoutManager layout)}.
33.  *
34.  * Created by Freddie (Musenkishi) Lust-Hed.
35.  */
36. public class GridRecyclerView extends
37.   
38. public
39. super(context);  
40.     }  
41.   
42. public
43. super(context, attrs);  
44.     }  
45.   
46. public GridRecyclerView(Context context, AttributeSet attrs, int
47. super(context, attrs, defStyle);  
48.     }  
49.   
50. @Override
51. public void
52. if (layout instanceof
53. super.setLayoutManager(layout);  
54. else
55. throw new ClassCastException(“You should only use a GridLayoutManager with GridRecyclerView.”);  
56.         }  
57.     }  
58.   
59. @Override
60. protected void attachLayoutAnimationParameters(View child, ViewGroup.LayoutParams params, int index, int
61.   
62. if (getAdapter() != null && getLayoutManager() instanceof
63.   
64.             GridLayoutAnimationController.AnimationParameters animationParams =  
65.                     (GridLayoutAnimationController.AnimationParameters) params.layoutAnimationParameters;  
66.   
67. if (animationParams == null) {  
68. new
69.                 params.layoutAnimationParameters = animationParams;  
70.             }  
71.   
72. int
73.   
74.             animationParams.count = count;  
75.             animationParams.index = index;  
76.             animationParams.columnsCount = columns;  
77.             animationParams.rowsCount = count / columns;  
78.   
79. final int invertedIndex = count - 1
80. 1
81. 1
82.   
83. else
84. super.attachLayoutAnimationParameters(child, params, index, count);  
85.         }  
86.     }  
87. }

/*
 * Copyright (C) 2014 Freddie (Musenkishi) Lust-Hed
 *
 * 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.musenkishi.gists.view;

import android.content.Context;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.GridLayoutAnimationController;

/**
 * An extension of RecyclerView, focused more on resembling a GridView.
 * Unlike {@link android.support.v7.widget.RecyclerView}, this view can handle
 * {@code <gridLayoutAnimation>} as long as you provide it a
 * {@link android.support.v7.widget.GridLayoutManager} in
 * {@code setLayoutManager(LayoutManager layout)}.
 *
 * Created by Freddie (Musenkishi) Lust-Hed.
 */
public class GridRecyclerView extends RecyclerView {

    public GridRecyclerView(Context context) {
        super(context);
    }

    public GridRecyclerView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public GridRecyclerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setLayoutManager(LayoutManager layout) {
        if (layout instanceof GridLayoutManager){
            super.setLayoutManager(layout);
        } else {
            throw new ClassCastException("You should only use a GridLayoutManager with GridRecyclerView.");
        }
    }

    @Override
    protected void attachLayoutAnimationParameters(View child, ViewGroup.LayoutParams params, int index, int count) {

        if (getAdapter() != null && getLayoutManager() instanceof GridLayoutManager){

            GridLayoutAnimationController.AnimationParameters animationParams =
                    (GridLayoutAnimationController.AnimationParameters) params.layoutAnimationParameters;

            if (animationParams == null) {
                animationParams = new GridLayoutAnimationController.AnimationParameters();
                params.layoutAnimationParameters = animationParams;
            }

            int columns = ((GridLayoutManager) getLayoutManager()).getSpanCount();

            animationParams.count = count;
            animationParams.index = index;
            animationParams.columnsCount = columns;
            animationParams.rowsCount = count / columns;

            final int invertedIndex = count - 1 - index;
            animationParams.column = columns - 1 - (invertedIndex % columns);
            animationParams.row = animationParams.rowsCount - 1 - invertedIndex / columns;

        } else {
            super.attachLayoutAnimationParameters(child, params, index, count);
        }
    }
}

配置布局动画

布局动画好的一面就是我们可以使用xml来定义与部署它们，因此我们的代码不会被动画穿插。我们只需用相应的布局动画定义xml。

1. <gridLayoutAnimation xmlns:android=“http://schemas.android.com/apk/res/android”
2. android:columnDelay=“15%”
3. android:rowDelay=“15%”
4. android:animation=“@anim/slide_in_bottom”
5. android:animationOrder=“normal”
6. android:direction=“top_to_bottom|left_to_right”/>

<gridLayoutAnimation xmlns:android="http://schemas.android.com/apk/res/android"
    android:columnDelay="15%"
    android:rowDelay="15%"
    android:animation="@anim/slide_in_bottom"
    android:animationOrder="normal"
    android:direction="top_to_bottom|left_to_right"/>

我们可以根据自己的喜好来自定义动画：

– columnDelay / rowDelay : 行元素与列元素在动画时的延迟时间百分数。这样我们才能让下一行下一列view一个接一个的动画，而不是一起动画。

– animation : view出现在屏幕上的动画，我使用的是从底部滑出的动画。

– animationOrder : 可以是 normal , reverse 或者 random .

– direction : 指定item如何基于列延迟显示出来，可取值：top_to_bottom , left_to_right , bottom_to_top , right_to_left。

这里是slide 动画的xml代码：

1. <translate xmlns:android=“http://schemas.android.com/apk/res/android”
2. android:interpolator=“@android:anim/decelerate_interpolator”
3. android:fromYDelta=“100%p” android:toYDelta=“0”
4. android:duration=“@android:integer/config_mediumAnimTime”/>

<translate xmlns:android="http://schemas.android.com/apk/res/android"
           android:interpolator="@android:anim/decelerate_interpolator"
           android:fromYDelta="100%p" android:toYDelta="0"
           android:duration="@android:integer/config_mediumAnimTime"/>

调整动画的时机

如果你执行现在的代码，你会发现app打开的同时布局动画也在执行，因此你其实看不到什么效果。对于Lollipop 之前的设备你没什么办法，没有有效的方法可以知道进入动画何时完成（至少我不知道）。但是从Lollipop 开始，我们可以使用onEnterAnimationComplete来检查。因此在onCreate中，如果SDK 版本旧于Lollipop，RecyclerView直接落定：

1. if
2.     setRecyclerAdapter(recyclerView);  
3. }

if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
    setRecyclerAdapter(recyclerView);
}

在Lollipop 或者更新设备，onEnterAnimationComplete会被调用。这是落定RecyclerView与请求新的布局动画的时机：

1. @Override
2. public void
3. super.onEnterAnimationComplete();  
4.     setRecyclerAdapter(recyclerView);  
5.     recyclerView.scheduleLayoutAnimation();  
6. }

@Override 
public void onEnterAnimationComplete() {
    super.onEnterAnimationComplete();
    setRecyclerAdapter(recyclerView);
    recyclerView.scheduleLayoutAnimation();
}

总结

你可以轻易调整此布局动画来产生别的进入动画。可以尝试弄弄动画设置看看能得到些什么效果。