Android加载Gif动画实现代码

Android加载Gif动画如何实现？相信大家都很好奇，本文就为大家揭晓，内容如下

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:orientation="vertical" > 

 <com.example.gifdemo.GifView
 android:id="@+id/gif1"
 android:layout_width="100dp"
 android:layout_height="100dp"
 android:layout_gravity="center_horizontal"
 android:enabled="false" /> 

</LinearLayout>

 <declare-styleable name="GifView">
 <attr name="gif" format="reference" />
 <attr name="paused" format="boolean" />
 </declare-styleable>

主界面

package com.example.gifdemo; 

import android.app.Activity;
import android.os.Bundle; 

public class MainActivity extends Activity {
 private GifView gif1; 

 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 gif1 = (GifView) findViewById(R.id.gif1);
 // 设置背景gif图片资源
 gif1.setMovieResource(R.raw.red);
 } 

}

自定义view

package com.example.gifdemo; 

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Movie;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View; 

public class GifView extends View { 

 /**
 * 默认为1秒
 */
 private static final int DEFAULT_MOVIE_DURATION = 1000; 

 private int mMovieResourceId; 

 private Movie mMovie; 

 private long mMovieStart; 

 private int mCurrentAnimationTime = 0; 

 private float mLeft; 

 private float mTop; 

 private float mScale; 

 private int mMeasuredMovieWidth; 

 private int mMeasuredMovieHeight; 

 private boolean mVisible = true; 

 private volatile boolean mPaused = false; 

 /**
 * 构造函数
 */
 public GifView(Context context) {
 this(context, null);
 } 

 public GifView(Context context, AttributeSet attrs) {
 this(context, attrs,0);
 } 

 public GifView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 setViewAttributes(context, attrs, defStyle);
 setBackgroundColor(Color.parseColor("#FFB6C1"));
 } 

 @SuppressLint("NewApi")
 private void setViewAttributes(Context context, AttributeSet attrs,
 int defStyle) {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
 setLayerType(View.LAYER_TYPE_SOFTWARE, null);
 }
 // 从描述文件中读出gif的值，创建出Movie实例
 final TypedArray array = context.obtainStyledAttributes(attrs,
 R.styleable.GifView);
 mMovieResourceId = array.getResourceId(R.styleable.GifView_gif, -1);
 mPaused = array.getBoolean(R.styleable.GifView_paused, false);
 array.recycle();
 if (mMovieResourceId != -1) {
 mMovie = Movie.decodeStream(getResources().openRawResource(
  mMovieResourceId));
 }
 } 

 /**
 * 设置gif图资源
 */
 public void setMovieResource(int movieResId) {
 this.mMovieResourceId = movieResId;
 mMovie = Movie.decodeStream(getResources().openRawResource(
 mMovieResourceId));
 requestLayout();
 } 

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 if (mMovie != null) {
 //gif动画的宽度、高度
 int movieWidth = mMovie.width();
 int movieHeight = mMovie.height();
 //控件的宽度
 int maximumWidth = MeasureSpec.getSize(widthMeasureSpec);
 //gif图片宽/控件宽
 float scaleW = (float) movieWidth / (float) maximumWidth;
 mScale = 1f / scaleW;
 mMeasuredMovieWidth = maximumWidth;
 mMeasuredMovieHeight = (int) (movieHeight * mScale);
 setMeasuredDimension(mMeasuredMovieWidth, mMeasuredMovieHeight);
 } else {
 setMeasuredDimension(getSuggestedMinimumWidth(),
  getSuggestedMinimumHeight());
 }
 } 

// @Override
// protected void onLayout(boolean changed, int l, int t, int r, int b) {
// super.onLayout(changed, l, t, r, b);
// mLeft = (getWidth() - mMeasuredMovieWidth) / 2f;
// mTop = (getHeight() - mMeasuredMovieHeight) / 2f;
// mVisible = getVisibility() == View.VISIBLE;
// } 

 @Override
 protected void onDraw(Canvas canvas) {
 if (mMovie != null) {
 if (!mPaused) {
 updateAnimationTime();
 drawMovieFrame(canvas);
 invalidateView();
 } else {
 drawMovieFrame(canvas);
 }
 }
 }
 private void updateAnimationTime() {
 long now = android.os.SystemClock.uptimeMillis();
 // 如果第一帧，记录起始时间
 if (mMovieStart == 0) {
 mMovieStart = now;
 }
 // 取出动画的时长
 int dur = mMovie.duration();
 if (dur == 0) {
 dur = DEFAULT_MOVIE_DURATION;
 }
 // 算出需要显示第几帧
 mCurrentAnimationTime = (int) ((now - mMovieStart) % dur);
 } 

 private void drawMovieFrame(Canvas canvas) {
 // 设置要显示的帧，绘制即可
 mMovie.setTime(mCurrentAnimationTime);
 canvas.save(Canvas.MATRIX_SAVE_FLAG);
 canvas.scale(mScale, mScale);
 mMovie.draw(canvas, mLeft / mScale, mTop / mScale);
 canvas.restore();
 } 

 @SuppressLint("NewApi")
 private void invalidateView() {
 if (mVisible) {
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
 postInvalidateOnAnimation();
 } else {
 invalidate();
 }
 }
 } 

 // --------------------以下方法未调用------------------------------------/
 public void setMovie(Movie movie) {
 this.mMovie = movie;
 requestLayout();
 } 

 public Movie getMovie() {
 return mMovie;
 } 

 public void setMovieTime(int time) {
 mCurrentAnimationTime = time;
 invalidate();
 } 

 public void setPaused(boolean paused) {
 this.mPaused = paused;
 if (!paused) {
 mMovieStart = android.os.SystemClock.uptimeMillis()
  - mCurrentAnimationTime;
 }
 invalidate();
 } 

 public boolean isPaused() {
 return this.mPaused;
 } 

 @SuppressLint("NewApi")
 @Override
 public void onScreenStateChanged(int screenState) {
 super.onScreenStateChanged(screenState);
 mVisible = screenState == SCREEN_STATE_ON;
 invalidateView();
 } 

 @SuppressLint("NewApi")
 @Override
 protected void onVisibilityChanged(View changedView, int visibility) {
 super.onVisibilityChanged(changedView, visibility);
 mVisible = visibility == View.VISIBLE;
 invalidateView();
 } 

 @Override
 protected void onWindowVisibilityChanged(int visibility) {
 super.onWindowVisibilityChanged(visibility);
 mVisible = visibility == View.VISIBLE;
 invalidateView();
 }
 // --------------------------------------------------------/
} 

源码下载：http://xiazai.jb51.net/201610/yuanma/AndroidGifDemo(jb51.net).rar

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。