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小牛知识库。