原文地址:http://blog.csdn.net/loongggdroid/article/details/21166563
整理下前輩的經驗，以後使用更方便，並對前輩的代碼進行一些補充註釋。
先上代碼:
package view;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Movie;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import com.pzhu.demo.R;
public class MyGifView extends View {
/**
* 默認爲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;
public MyGifView(Context context) {
this(context, null);
}
public MyGifView(Context context, AttributeSet attrs) {
this(context, attrs, R.styleable.CustomTheme_gifViewStyle);
}
public MyGifView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
setViewAttributes(context, attrs, defStyle);
}
@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);
}
//加載屬性文件，獲取在佈局文件中控件的屬性值
final TypedArray array = context.obtainStyledAttributes(attrs,
R.styleable.GifView); // R.styleable.GifView爲attrs.xml中的屬性集
mMovieResourceId = array.getResourceId(R.styleable.GifView_gif, -1); //獲取佈局文件中gif圖片的資源，需設置attr:gif="資源文件位置"屬性
//這裏是佈局文件中gif資源設置沒有起始暫停狀態屬性,沒設置這個屬性默認自動播放
mPaused = array.getBoolean(R.styleable.GifView_paused, false);
array.recycle();
if (mMovieResourceId != -1) {
mMovie = Movie.decodeStream(getResources().openRawResource(
mMovieResourceId));
}
}
/**
* 設置gif圖資源
* 可以自己在代碼調用此方法設置不同的gif資源
* @param movieResId
*/
public void setMovieResource(int movieResId) {
this.mMovieResourceId = movieResId;
mMovie = Movie.decodeStream(getResources().openRawResource(
mMovieResourceId));
requestLayout();
}
/**
* 設置Movie
* 如果不想要gif的Movie 可自行設置，用gif的足矣
* @param movieResId
*/
public void setMovie(Movie movie) {
this.mMovie = movie;
requestLayout();
}
public Movie getMovie() {
return mMovie;
}
public void setMovieTime(int time) {
mCurrentAnimationTime = time;
invalidate();
}
/**
* 設置暫停
* 此暫停也就是控制gif圖片的播放 true爲暫停，可自行在代碼裏調用實現需求，比如在點擊後暫停播放或者開始播放，可在佈局文件中設置這個值，效果爲自動播放或者不自 * 動播放
* @param paused
*/
public void setPaused(boolean paused) {
this.mPaused = paused;
if (!paused) {
mMovieStart = android.os.SystemClock.uptimeMillis()
- mCurrentAnimationTime;
}
invalidate();
}
/**
* 判斷gif圖是否停止了
*
* @return
*/
public boolean isPaused() {
return this.mPaused;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (mMovie != null) {
int movieWidth = mMovie.width();
int movieHeight = mMovie.height();
int maximumWidth = MeasureSpec.getSize(widthMeasureSpec);
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);
}
}
}
@SuppressLint("NewApi")
private void invalidateView() {
if (mVisible) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
postInvalidateOnAnimation();
} else {
invalidate();
}
}
}
private void updateAnimationTime() {
long now = android.os.SystemClock.uptimeMillis();
// 如果第一幀，記錄起始時間
if (mMovieStart == 0) {
mMovieStart = now;
}
// 取出動畫的時長
int dur = mMovie.duration();
if (dur == 0) {
dur = DEFAULT_MOVIE_DURATION;
}
// 算出需要顯示第幾幀
mCurrentAnimationTime = (int) ((now - mMovieStart) % dur);
}
private void drawMovieFrame(Canvas canvas) {
// 設置要顯示的幀，繪製即可
mMovie.setTime(mCurrentAnimationTime);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(mScale, mScale);
mMovie.draw(canvas, mLeft / mScale, mTop / mScale);
canvas.restore();
}
@SuppressLint("NewApi")
@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();
}
}
需要在values目錄下的attrs.xml文件(沒有自行創建)中定義好自定義屬性 如下:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="GifView">
<attr name="gif" format="reference" />
<attr name="paused" format="boolean" />
</declare-styleable>
<declare-styleable name="CustomTheme">
<attr name="gifViewStyle" format="reference" />
</declare-styleable>
</resources>