binbinyang---Android实现显示GIF图片

最近.一个朋友跟我说想,我给她弄个闹钟APP软件...功能其实很简单...只需要弄个简单的闹钟.自己设计设计时间.然后时间到了的时候,闹铃放的声音是男朋友录制好的声音...于是就开始整了....

第一次做这种的时候.我想把首页界面做成一个GIF动画特效的.这样看起来可爱点...适合妹子用,于是就有了下面这个效果图


  

上代码

ndroid中的android.graphics.Movie 这个类，这是android提供给我们的一个非常方便的工具。

首先，重写控件View,自定义一个展示gif图的GifView
Movie其实管理着GIF动画中的多个帧，只需要通过 setTime() 一下就可以让它在draw()的时候绘出相应的那帧图像。通过当前时间与duration之间的换算关系，是很容易实现GIF动起来的效果。

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;

public GifView(Context context) {
this(context, null);
}

public GifView(Context context, AttributeSet attrs) {
this(context, attrs, R.styleable.CustomTheme_gifViewStyle);
}

public GifView(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);
}
// 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, defStyle, R.style.Widget_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
*
* @param movieResId
*/
public void setMovieResource(int movieResId) {
this.mMovieResourceId = movieResId;
mMovie = Movie.decodeStream(getResources().openRawResource(
mMovieResourceId));
requestLayout();
}

public void setMovie(Movie movie) {
this.mMovie = movie;
requestLayout();
}

public Movie getMovie() {
return mMovie;
}

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

/**
* 设置暂停
*
* @param paused
*/
public void setPaused(boolean paused) {
this.mPaused = paused;
if (!paused) {
mMovieStart = android.os.SystemClock.uptimeMillis()
- mCurrentAnimationTime;
}
invalidate();
}

/**
* 判断gif图是否停止了
*
* @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")
@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();
}

}

其次，在xml布局文件中，把这个view定义进去，代码如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ffffff"
android:gravity="center"
android:orientation="vertical"
>

<com.example.alarmtest.GifView
android:id="@+id/gif1"
android:layout_width="300dp"
android:layout_height="300dp"
android:layout_gravity="center_horizontal"
android:enabled="false"/>

<Button
android:id="@+id/bu"
android:text="进入"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"/>

</LinearLayout>

最后，在MainActivity中的使用，代码如下：

public class FirstActivity extends Activity {

private GifView gif;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_first);

gif = (GifView) findViewById(R.id.gif1);
// 设置背景gif图片资源
gif.setMovieResource(R.raw.a123);

}

}

Styles.xml

<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>

<style name="Widget_GifView"></style>

raw是res下面的一个文件放的是GIF动画图噢
我这里放了一个动画图 跟一个 音乐文件,因为我要做的是一个有声音的闹铃