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)

 <com.p.h.ExpandLayout
        android:id="@+id/expandLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#FFFF00"
        android:clickable="true">

        <TextView
            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" />

    </com.p.h.ExpandLayout>

• 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:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    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">

    <Button
        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" />


    <com.p.h.ExpandLayout
        android:id="@+id/expandLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#FFFF00"
        android:clickable="true">

        <TextView
            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" />

    </com.p.h.ExpandLayout>

</LinearLayout>

• 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~~~