这一次让你彻底了解 Android Frame Animation

1. 什么是 FrameAnimation？

通过一定顺序展示一系列的图像而形成的动画叫帧动画。

Creates an animation by showing a sequence of images in order with an AnimationDrawable

其实我们平时看的电影、电视剧都是由一帧一帧的画面组成的：

战斗天使阿丽塔

所以从某种意义上说，电影和电视剧也是帧动画，只不过电影、电视剧较长而且有声音。

2. FrameAnimation 的作用是什么？

从上面的定义可知，帧动画的主要作用是按照一定的顺序展示一系列图片。

3. 如何使用 FrameAnimation？

FrameAnimation 创建方式有两种：

1. XML
2. CODE

3.1 通过 XML 创建 FrameAnimation

3.1.1 语法

3.1.1.2. 属性详解

属性	含义	取值范围
xmlns:android	声明 XML 布局文件属性命名空间	http://schemas.android.com/apk/res/android
android:oneshot	是否只播放一次	true 仅播放一次，false 一直循环播放（默认 false）
android:drawable	FrameAnimation 中每一帧的图片	Drawable 资源
android:duration	FrameAnimation 中每一帧图片持续时间	必须大于等于 0，否则程序将报错

3.1.1.3. 示例

最终效果如下：

Frame Animation (XML)

3.2 通过 CODE 创建 FrameAnimation

3.2.1 语法

AnimationDrawable drawable = new AnimationDrawable();
drawable.setOneShot(boolean oneShot);
drawable.addFrame(Drawable frame, int duration);
...
ImageView.setBackground(drawable);
drawable.start();
drawable.stop();

3.2.2 示例

AnimationDrawable mAnimationDrawable = new AnimationDrawable();
mAnimationDrawable.setOneShot(false);
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_001),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_002),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_003),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_004),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_005),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_006),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_007),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_008),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_009),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_010),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_011),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_012),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_013),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_014),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_015),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_016),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_017),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_018),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_019),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_020),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_021),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_022),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_023),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_024),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_025),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_026),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_027),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_028),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_029),getResources().getInteger(R.integer.integer_twenty));
mAnimationDrawable.addFrame(getResources().getDrawable(R.drawable.people_030),getResources().getInteger(R.integer.integer_twenty));
mTarget.setBackground(mAnimationDrawable);
mAnimationDrawable.start();

最终效果如下：

Frame Animation (CODE)

4. 应用实例

早些时候，很多软件的等待对话框都是通过 FrameAnimation + Dialog 实现的，最经典的例子当属大众点评，不过昨晚再去看的时候，发现大众点评早已“面目全非”，那我们自己动手写一个吧。

//1. 自定义 Dialog

//1.1 Dialog 布局文件


    
//1.2 Dialog 类
public class CustomDialog extends Dialog {


    public CustomDialog(Context context) {
        super(context, R.style.CustomDialog);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dialog_custom);
    }

}

//2. 应用自定义 Dialog

//2.1 Activity 布局文件



    



//2.2 Activity 类
public class FrameAnimationApplicationActivity extends AppCompatActivity implements View.OnClickListener, Dialog.OnShowListener, Dialog.OnDismissListener {

    private Button mTarget;
    private Dialog mDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_frame_animation_application);
        initView();
        initData();
    }

    private void initView(){
        mTarget = findViewById(R.id.frame_animation_target);
        mTarget.setOnClickListener(this);
    }

    private void initData(){

    }

    @Override
    public void onClick(View v) {
        showDialog();
    }

    private void showDialog(){
        mDialog = new CustomDialog(this);
        mDialog.setOnShowListener(this);
        mDialog.setOnDismissListener(this);
        mDialog.show();

    }

    @Override
    public void onDismiss(DialogInterface dialog) {
        ImageView target = mDialog.findViewById(R.id.custom_dialog_target);
        AnimationDrawable animationDrawable = (AnimationDrawable)target.getBackground();
        animationDrawable.stop();
        mTarget.setVisibility(View.VISIBLE);
    }

    @Override
    public void onShow(DialogInterface dialog) {
        ImageView target = mDialog.findViewById(R.id.custom_dialog_target);
        AnimationDrawable animationDrawable = (AnimationDrawable)target.getBackground();
        animationDrawable.start();
        mTarget.setVisibility(View.GONE);
    }
    
}

最终效果如下：

FrameAnimation & Dialog

我在这里只是抛砖引玉，FrameAnimation 的更多有意思的用法还要靠小伙伴发挥自己的想象力去想。

5. 参考文献

1. Animation resources
2. AnimationDrawable