旋转图像.动画列表或动画旋转?(安卓) [英] Rotating image. Animation list or animated rotate? (Android)

问题描述

我想创建一个旋转进度图像，并想知道最好的方法是什么.我可以使它与动画列表一起使用，例如每 100 毫秒更改 12 个图像.这很好用，但创建 12 个图像或为每个尺寸和分辨率创建非常乏味:

I want to create a rotating progress image, and wonder what's the best way to proceed. I can make it work with an animation list with for example 12 images changing every 100ms. This works fine, but it's quite tedious to create 12 images or for every size and resolution:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false">
<item android:drawable="@drawable/ic_loading_grey_on_black_01" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_02" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_03" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_04" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_05" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_06" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_07" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_08" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_09" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_10" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_11" android:duration="100" />
<item android:drawable="@drawable/ic_loading_grey_on_black_12" android:duration="100" />

我认为更简单的解决方案是每个分辨率使用一个图像，而是为每一帧旋转它.在平台资源(android-sdk-windows/platforms...)中，我在文件 drawable/search_spinner.xml 中发现了一个叫做 animation-rotate 的东西，但是如果我复制代码会得到一个编译器错误，抱怨 android:framesCount 和 android:frameDuration(Eclipse 中的 Google API 2.2):

I suppose that an easier solution is to use one image per resolution, but rather rotate it for each frame. In the platform resources (android-sdk-windows/platforms...) I found something called animated-rotate in the file drawable/search_spinner.xml, but if I copy the code get a compiler error complaining about android:framesCount and android:frameDuration (Google APIs 2.2 in Eclipse):

<animated-rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/spinner_black_20"
android:pivotX="50%"
android:pivotY="50%"
android:framesCount="12"
android:frameDuration="100" />

我也尝试过使用重复旋转动画(在动画资源文件夹中使用)，但我实际上更喜欢动画列表版本的外观.

I have also tried using a repeating rotate animation (using in the anim resource folder), but I actually prefer the look of the animation list version.

解决此问题的推荐方法是什么?

What is the recommended way of solving this problem?

推荐答案

Rotate drawable 由 Praveen 建议不会让你控制帧数.假设您要实现一个由 8 个部分组成的自定义加载器:

Rotate drawable suggested by Praveen won't give you control of frame count. Let's assume you want to implement a custom loader which consists from 8 sections:

使用 animation-list 方法，您需要手动创建旋转 45*frameNumber 度的 8 帧.或者，您可以使用第一帧并为其设置旋转动画:

Using animation-list approach, you need to create 8 frames rotated by 45*frameNumber degrees manually. Alternatively, you can use 1st frame and set rotation animation to it:

文件res/anim/progress_anim.xml:

<?xml version="1.0" encoding="utf-8"?>
<rotate
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:fromDegrees="0"
    android:toDegrees="360"
    android:pivotX="50%"
    android:pivotY="50%"
    android:repeatCount="infinite" />

文件 MainActivity.java

Animation a = AnimationUtils.loadAnimation(getContext(), R.anim.progress_anim);
a.setDuration(1000);
imageView.startAnimation(a);

这将为您提供流畅的动画，而不是 8 步.为了解决这个问题，我们需要实现自定义插值器:

This will give you smooth animation instead of 8-stepped. To fix this we need to implement custom interpolator:

a.setInterpolator(new Interpolator() {
    private final int frameCount = 8;

    @Override
    public float getInterpolation(float input) {
        return (float)Math.floor(input*frameCount)/frameCount;
    }
});

您也可以创建自定义小部件:

Also you can create a custom widget:

文件res/values/attrs.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="ProgressView">
        <attr name="frameCount" format="integer"/>
        <attr name="duration" format="integer" />
    </declare-styleable>
</resources>

文件ProgressView.java:

public class ProgressView extends ImageView {

    public ProgressView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        setAnimation(attrs);
    }

    public ProgressView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setAnimation(attrs);
    }

    public ProgressView(Context context) {
        super(context);
    }

    private void setAnimation(AttributeSet attrs) {
        TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.ProgressView);
        int frameCount = a.getInt(R.styleable.ProgressView_frameCount, 12);  
        int duration = a.getInt(R.styleable.ProgressView_duration, 1000);
        a.recycle();

        setAnimation(frameCount, duration);
    }

    public void setAnimation(final int frameCount, final int duration) {
        Animation a = AnimationUtils.loadAnimation(getContext(), R.anim.progress_anim);
        a.setDuration(duration);
        a.setInterpolator(new Interpolator() {

            @Override
            public float getInterpolation(float input) {
                return (float)Math.floor(input*frameCount)/frameCount;
            }
        });
        startAnimation(a);
    }
}

文件activity_main.xml:

<com.example.widget.ProgressView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_progress" 
    app:frameCount="8"
    app:duration="1000"/>

文件res/anim/progress_anim.xml:上面列出

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