android动画使用三

来源：互联网发布：机械能守恒实验带数据编辑：程序博客网时间：2024/05/17 20:28

使用ValueAnimator实现一个点击view展示次级view的效果

效果图：
valueAnimator展开次级菜单

代码：
MainActivity.java

package com.example.lhd.myvalueanimator;import android.animation.Animator;import android.animation.AnimatorListenerAdapter;import android.animation.ValueAnimator;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import android.widget.RelativeLayout;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private Button btn1;    private RelativeLayout r2;    private float mDensity;//屏幕密度    private int r2Height;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        init();        //将dp转换为px        mDensity = getResources().getDisplayMetrics().density;        //获取隐藏布局的高度  mDensity * 100dp + 0.5f        r2Height = (int) (mDensity * 100 + 0.5);    }    private void init() {        r2 = (RelativeLayout) findViewById(R.id.r2);        btn1 = (Button) findViewById(R.id.btn_1);        btn1.setOnClickListener(this);    }    @Override    public void onClick(View v) {        if (r2.getVisibility() == View.GONE) {            //展开动画            btn1.setText("-");            open(r2);        } else {            //关闭动画            close(r2);            btn1.setText("+");        }    }    private void open(View view) {        view.setVisibility(View.VISIBLE);        ValueAnimator animator = openAnimator(view, 0, r2Height);        animator.start();    }    private void close(final View view) {        int curheight = view.getHeight();        ValueAnimator animator = openAnimator(view, curheight, 0);//由现在的高度变回为0        animator.addListener(new AnimatorListenerAdapter() {            @Override            public void onAnimationEnd(Animator animation) {                view.setVisibility(View.GONE);//动画执行结束后让布局隐藏            }        });        animator.start();    }    private ValueAnimator openAnimator(final View view, int start, int end) {        ValueAnimator animator = ValueAnimator.ofInt(start, end);        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator animation) {                int value = (int) animation.getAnimatedValue();                ViewGroup.LayoutParams lp = view.getLayoutParams();                lp.height = value;//高度不断变化，由start到end                view.setLayoutParams(lp);            }        });        return animator;    }}

布局文件：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <RelativeLayout        android:id="@+id/r1"        android:layout_width="match_parent"        android:layout_height="40dp"        android:background="#0fa">        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_centerInParent="true"            android:text="ValueAnimator"            android:textSize="18sp" />        <Button            android:id="@+id/btn_1"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_alignParentRight="true"            android:background="#fff"            android:text="+"            android:textSize="30sp" />    </RelativeLayout>    <!-- 隐藏布局的高度为100dp -->    <RelativeLayout        android:visibility="gone"        android:id="@+id/r2"        android:layout_width="match_parent"        android:layout_height="100dp"        android:background="#fa0">        <ImageView            android:layout_width="100dp"            android:layout_height="100dp"            android:background="@drawable/xixi" />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_centerInParent="true"            android:text="展开的内容"            android:textColor="#fff"            android:textSize="20sp" />        <Button            android:id="@+id/btn_2"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_alignParentRight="true"            android:layout_centerVertical="true"            android:background="#0fa"            android:text="(*^__^*)"            android:textSize="30sp" />    </RelativeLayout></LinearLayout>

图片素材：

demo下载：
http://dl.download.csdn.net/down11/20160609/7ad708a192f47edc1993f5898486d031.zip?response-content-disposition=attachment%3Bfilename%3D%22MyValueAnimator.zip%22&OSSAccessKeyId=9q6nvzoJGowBj4q1&Expires=1465699930&Signature=4ISctwgPfYaJaAq%2BvC0nkSiiPt4%3D

1 0