android中播放gif动画之二

水深无声 2022-01-14 11:43 184阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

在上一篇，是使用代码通过构造方法传入要播放的gif动画的id进行获取的。本文进一步改造，让GifView和ImageView一样可以在布局文件中设置src属性，并在GifView中我们使用反射动态获取src的图片资源ID，然后对它进行播放。这样使用起来就灵活多了。代码如下：

GifView：

package com.home.gifview; import java.io.InputStream; import java.lang.reflect.Field; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Movie; import android.os.SystemClock; import android.util.AttributeSet; import android.util.TypedValue; import android.widget.ImageView; public class GifView extends ImageView { private Movie movie; private long movieStart; private int imageWidth; private int imageHeight; public GifView(Context context) { super(context); } public GifView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public GifView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.GifView); int resourceId = getResourceId(a, context, attrs); if (resourceId != 0) { InputStream is = getResources().openRawResource(resourceId); movie = Movie.decodeStream(is); if (movie != null) { Bitmap bitmap = BitmapFactory.decodeStream(is); imageWidth = bitmap.getWidth(); imageHeight = bitmap.getHeight(); bitmap.recycle(); } } } @Override protected void onDraw(Canvas canvas) { if (movie == null) { // 普通图片则直接调用父类的onDraw()方法 super.onDraw(canvas); } else { playGif(canvas); invalidate(); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (movie != null) { // 如果是gif图片则定制GifView的大小 setMeasuredDimension(imageWidth, imageHeight); } } /** * 播放gif动画 * * @param canvas * @return */ private boolean playGif(Canvas canvas) { long now = SystemClock.uptimeMillis(); if (movieStart == 0) { movieStart = now; } int duration = movie.duration(); if (duration == 0) { duration = 1000; } int relTime = (int) ((now - movieStart) % duration); movie.setTime(relTime); movie.draw(canvas, 0, 0); if ((now - movieStart) >= duration) { movieStart = 0; return true; } return false; } /** * 使用反射，获取到src指定图片资源所对应的id。 * * @param a * @param context * @param attrs * @return */ private int getResourceId(TypedArray a, Context context, AttributeSet attrs) { try { Field field = TypedArray.class.getDeclaredField("mValue"); field.setAccessible(true); TypedValue typedValueObject = (TypedValue) field.get(a); return typedValueObject.resourceId; } catch (Exception e) { e.printStackTrace(); } finally { if (a != null) { a.recycle(); } } return 0; } }

attrs.xml：

<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="GifView"></declare-styleable> </resources>

main.xml：

禁用硬件加速：

android:hardwareAccelerated="false"

转载于:https://my.oschina.net/secyaher/blog/274414

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220114/3a337daa0f054697a4194a71d4fca55e.png