SVG动画示例

package com.loaderman.customviewdemo;

import android.graphics.drawable.Animatable;
import android.os.Bundle;
import android.support.graphics.drawable.AnimatedVectorDrawableCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.AppCompatDelegate;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    static {
        AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ImageView imageView = (ImageView) findViewById(R.id.anim_img);
                AnimatedVectorDrawableCompat animatedVectorDrawableCompat = AnimatedVectorDrawableCompat.create(
                        MainActivity.this, R.drawable.line_animated_vector
                );
                imageView.setImageDrawable(animatedVectorDrawableCompat);
                ((Animatable) imageView.getDrawable()).start();
            }
        });

    }

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <Button
        android:id="@+id/btn"
        android:text="开始动画"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />
    <ImageView
        android:id="@+id/anim_img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/svg_line"/>
</LinearLayout>

line_animated_vector.xml

<?xml version="1.0" encoding="utf-8"?>
<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:drawable="@drawable/svg_line">

    <target
            android:name="bar"
            android:animation="@animator/anim_trim_start"
            />
</animated-vector>

anim_trim_start.xml

<?xml version="1.0" encoding="utf-8"?>
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
        android:propertyName="trimPathStart"
        android:valueFrom="0"
        android:valueTo="1"
        android:duration="2000"/>

效果:

---

package com.loaderman.customviewdemo;

import android.graphics.drawable.Animatable;
import android.os.Bundle;
import android.support.graphics.drawable.AnimatedVectorDrawableCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.AppCompatDelegate;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    static {
        AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final ImageView imageView = (ImageView) findViewById(R.id.anim_img);

        //将焦点放在ImageView上
        imageView.setFocusable(true);
        imageView.setFocusableInTouchMode(true);
        imageView.requestFocus();
        imageView.requestFocusFromTouch();
        EditText editText = (EditText)findViewById(R.id.edit);

        //当EditText获得焦点时开始动画
        editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if (hasFocus){

                    AnimatedVectorDrawableCompat animatedVectorDrawableCompat = AnimatedVectorDrawableCompat.create(
                            MainActivity.this, R.drawable.animated_vecotr_search
                    );
                    imageView.setImageDrawable(animatedVectorDrawableCompat);
                    ((Animatable) imageView.getDrawable()).start();
                }
            }
        });

    }

}

animated_vecotr_search.xml

<?xml version="1.0" encoding="utf-8"?>
<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:drawable="@drawable/vector_search_bar" >
    <target
        android:animation="@animator/anim_search_trim_end"
        android:name="search"/>
    <target
        android:animation="@animator/anim_bar_trim_start"
        android:name="bar"/>
</animated-vector>

vector_search_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="150dp"
    android:height="24dp"
    android:viewportWidth="150"
    android:viewportHeight="24">

    <!--搜索条-->
    <path
        android:name="search"
        android:pathData="M141,17 A9,9 0 1,1 142,16 L149,23"
        android:strokeWidth="2"
        android:strokeColor="@android:color/darker_gray"/>

    <!--底部横线-->
    <path
        android:name="bar"
        android:trimPathStart="1"
        android:pathData="M0,23 L149,23"
        android:strokeWidth="2"
        android:strokeColor="@android:color/darker_gray"/>
</vector>

anim_search_trim_end.xml

<?xml version="1.0" encoding="utf-8"?>
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="500"
    android:propertyName="trimPathEnd"
    android:valueFrom="0"
    android:valueTo="1"
    android:valueType="floatType" />

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_marginTop="20dp"
    android:layout_marginLeft="20dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <EditText
        android:id="@+id/edit"
        android:hint="点击输入"
        android:layout_width="150dp"
        android:layout_height="24dp"
        android:background="@null"/>
    <ImageView
        android:id="@+id/anim_img"
        android:layout_width="150dp"
        android:layout_height="24dp"
        />
</FrameLayout>

效果: