android 點擊下彈動畫實現

下彈動畫的實現

DropDownExample.java

package com.buptfarmer.devapp;import com.nineoldandroids.animation.Animator;import com.nineoldandroids.animation.AnimatorListenerAdapter;import com.nineoldandroids.animation.ValueAnimator;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;public class DropDownExample extends Activity implements OnClickListener {    private View mHolder;    private View mHolder2;//    private static final int DURATION = 2000;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        initView();    }    private void initView() {        setContentView(R.layout.drop_down_example);        mHolder = findViewById(R.id.holder);        mHolder2 = findViewById(R.id.holder2);        mHolder.setOnClickListener(this);        mHolder2.setOnClickListener(this);    }    public static ValueAnimator createHeightAnimator(final View view, int start, int end) {        ValueAnimator animator = ValueAnimator.ofInt(start, end);        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator valueAnimator) {                int value = (Integer) valueAnimator.getAnimatedValue();                ViewGroup.LayoutParams layoutParams = view.getLayoutParams();                layoutParams.height = value;                view.setLayoutParams(layoutParams);            }        });//        animator.setDuration(DURATION);        return animator;    }    public static void animateExpanding(final View view) {        view.setVisibility(View.VISIBLE);        final int widthSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);        final int heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);        view.measure(widthSpec, heightSpec);        ValueAnimator animator = createHeightAnimator(view, 0, view.getMeasuredHeight());        animator.start();    }    public static void animateCollapsing(final View view) {        int origHeight = view.getHeight();        ValueAnimator animator = createHeightAnimator(view, origHeight, 0);        animator.addListener(new AnimatorListenerAdapter() {            public void onAnimationEnd(Animator animation) {                view.setVisibility(View.GONE);            };        });        animator.start();    }    @Override    public void onClick(View v) {        if (v == mHolder) {            if (View.GONE == mHolder.findViewById(R.id.hiddenview).getVisibility()) {                animateExpanding(mHolder.findViewById(R.id.hiddenview));            } else {                animateCollapsing(mHolder.findViewById(R.id.hiddenview));            }        } else if (v == mHolder2) {            if (View.GONE == mHolder2.findViewById(R.id.hiddenview).getVisibility()) {                animateExpanding(mHolder2.findViewById(R.id.hiddenview));            } else {                animateCollapsing(mHolder2.findViewById(R.id.hiddenview));            }        }    }}

drop_down_example.xml

<?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" >    <LinearLayout        android:id="@+id/holder"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:background="@color/greenyellow"        android:orientation="vertical" >        <LinearLayout            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:gravity="center_vertical"            android:orientation="horizontal"            android:paddingLeft="1dp" >            <ImageView                android:id="@+id/app_icon"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center"                android:contentDescription="picture"                android:minWidth="32dp"                android:src="@drawable/ic_launcher" />            <TextView                android:id="@+id/app_label"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_marginLeft="5dp"                android:ellipsize="end"                android:gravity="left"                android:singleLine="true"                android:text="what's your dream?"                android:textSize="13sp" />        </LinearLayout>        <LinearLayout            android:id="@+id/hiddenview"            android:layout_width="fill_parent"            android:layout_height="40dp"            android:gravity="center_vertical"            android:orientation="horizontal"            android:paddingLeft="1dp"            android:visibility="gone" >            <TextView                android:id="@+id/hidden_text"                android:layout_width="wrap_content"                android:layout_height="fill_parent"                android:text="過個好年，馬上有房" />        </LinearLayout>    </LinearLayout>    <LinearLayout        android:id="@+id/holder2"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:background="@color/blueviolet"        android:orientation="vertical" >        <LinearLayout            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:gravity="center_vertical"            android:orientation="horizontal"            android:paddingLeft="1dp" >            <ImageView                android:id="@+id/app_icon"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center"                android:contentDescription="picture"                android:minWidth="32dp"                android:src="@drawable/ic_launcher" />            <TextView                android:id="@+id/app_label"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_marginLeft="5dp"                android:ellipsize="end"                android:gravity="left"                android:singleLine="true"                android:text="Self introduction"                android:textSize="13sp" />        </LinearLayout>        <LinearLayout            android:id="@+id/hiddenview"            android:layout_width="fill_parent"            android:layout_height="40dp"            android:gravity="center_vertical"            android:orientation="horizontal"            android:paddingLeft="1dp"            android:visibility="gone" >            <ImageView                 android:contentDescription="avatar"                android:src="@drawable/avatar"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center"/>            <TextView                android:id="@+id/hidden_text"                android:layout_width="wrap_content"                android:layout_height="fill_parent"                android:text="樂山好事，積極樂觀" />        </LinearLayout>    </LinearLayout></LinearLayout>