简介:

由于界面View.VISIBLE和View.GONE的动画太生硬，所以写了ExpandLayout类来平滑过渡。 基本思路，动态的设置布局的高度。

先上效果图:

expand.gif

核心动画效果代码

/**

* 切换动画实现

*/

private void animateToggle(long animationDuration) {

ValueAnimator heightAnimation = isExpand ?

ValueAnimator.ofFloat(0f, viewHeight) : ValueAnimator.ofFloat(viewHeight, 0f);

heightAnimation.setDuration(animationDuration / 2);

heightAnimation.setStartDelay(animationDuration / 2);

heightAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

float val = (float) animation.getAnimatedValue();

setViewHeight(layoutView, (int) val);

}

});

heightAnimation.start();

}

使用:

布局文件中 (引入自定义View)

android:id="@+id/expandLayout"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:background="#FFFF00"

android:clickable="true">

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:gravity="center"

android:padding="15dp"

android:text="大辉儿: 这里是可收缩布局内部" />

java代码中 初始状态是否显示，toggleExpand切换折叠/展开状态

private ExpandLayout mExpandLayout;

public void initExpandView() {

mExpandLayout = (ExpandLayout) findViewById(R.id.expandLayout);

mExpandLayout.initExpand(false);//设定初始化折叠，默认展开

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

mExpandLayout.toggleExpand();

}

});

}

下面是全部代码:

布局文件:

xmlns:app="http://schemas.android.com/apk/res-auto"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:paddingTop="50dp">

android:id="@+id/button"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:background="#32CD32"

android:text="点击展开/收缩" />

android:id="@+id/expandLayout"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:background="#FFFF00"

android:clickable="true">

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:gravity="center"

android:padding="15dp"

android:text="大辉儿: 这里是可收缩布局内部" />

自定义View 伸缩布局类:

package com.p.h;

import android.animation.ValueAnimator;

import android.content.Context;

import android.util.AttributeSet;

import android.view.View;

import android.view.ViewGroup;

import android.widget.RelativeLayout;

/**

* Created by : Pan_Hui on

* Time: 2020/07/27 13:14

* 带过渡动画的折叠收缩布局

*/

public class ExpandLayout extends RelativeLayout {

public ExpandLayout(Context context) {

this(context, null);

}

public ExpandLayout(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

public ExpandLayout(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

initView();

}

private View layoutView;

private int viewHeight;

private boolean isExpand;

private long animationDuration;

private boolean lock;

private void initView() {

layoutView = this;

isExpand = true;

animationDuration = 300;

setViewDimensions();

}

/**

* @param isExpand 初始状态是否折叠

*/

public void initExpand(boolean isExpand) {

this.isExpand = isExpand;

setViewDimensions();

}

/**

* 设置动画时间

*

* @param animationDuration 动画时间

*/

public void setAnimationDuration(long animationDuration) {

this.animationDuration = animationDuration;

}

/**

* 获取subView的总高度

* View.post()的runnable对象中的方法会在View的measure、layout等事件后触发

*/

private void setViewDimensions() {

layoutView.post(new Runnable() {

@Override

public void run() {

if (viewHeight <= 0) {

viewHeight = layoutView.getMeasuredHeight();

}

setViewHeight(layoutView, isExpand ? viewHeight : 0);

}

});

}

public static void setViewHeight(View view, int height) {

final ViewGroup.LayoutParams params = view.getLayoutParams();

params.height = height;

view.requestLayout();

}

/**

* 切换动画实现

*/

private void animateToggle(long animationDuration) {

ValueAnimator heightAnimation = isExpand ?

ValueAnimator.ofFloat(0f, viewHeight) : ValueAnimator.ofFloat(viewHeight, 0f);

heightAnimation.setDuration(animationDuration / 2);

heightAnimation.setStartDelay(animationDuration / 2);

heightAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

int value = (int) (float) animation.getAnimatedValue();

setViewHeight(layoutView, value);

if (value == viewHeight || value == 0) {

lock = false;

}

}

});

heightAnimation.start();

lock = true;

}

public boolean isExpand() {

return isExpand;

}

/**

* 折叠view

*/

public void collapse() {

isExpand = false;

animateToggle(animationDuration);

}

/**

* 展开view

*/

public void expand() {

isExpand = true;

animateToggle(animationDuration);

}

public void toggleExpand() {

if (lock) {

return;

}

if (isExpand) {

collapse();

} else {

expand();

}

}

}

MainActivity中绑定使用自定义View

package com.p.h;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

public class MainActivity extends AppCompatActivity {

private Button button;

private ExpandLayout mExpandLayout;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

button = (Button) findViewById(R.id.button);

//初始化展开View

initExpandView();

}

public void initExpandView() {

mExpandLayout = (ExpandLayout) findViewById(R.id.expandLayout);

//初始状态是否折叠false 否 true 是

mExpandLayout.initExpand(false);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

mExpandLayout.toggleExpand();

}

});

}

}

最近有点忙,没时间更新 抱歉~~~