去除Android中一帧动画的背景

Question

如何删除帧动画的背景（或将其设置为透明）？

当我将xml布局文件中的背景颜色设置为透明时，运行它时它会变成黑色。

当我setBackgroundColor(0); 在Java 代码中，我收到以下异常：

java.lang.ClassCastException: android.graphics.drawable.ColorDrawable cannot be cast to android.graphics.drawable.AnimationDrawable

/res/layout/dialog_loading.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="@drawable/background_black_semitransparent" >
    <!-- The background of this LinearLayout is so that there is 
         a semi transparent black overlay over the application content 
         while the loading animation plays -->

    <FrameLayout
        android:layout_width="@dimen/dialog_width"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:background="@android:color/transparent" >

        <ImageView
            android:id="@+id/iv_loading"
            android:layout_width="@dimen/dialog_width"
            android:layout_height="wrap_content"
            android:scaleType="fitCenter"
            android:adjustViewBounds="true"
            android:background="@android:color/transparent" />

    </FrameLayout>

</LinearLayout>

/res/anim/frame_animation.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- The animation is defined by the animation-list element. The oneshot attribute defines whether or not the animation loops.
Each image is placed in a separate item elementwith the drawable attribute specifying the image file in /res/drawable/. 
The duration attribute specifies the time delay between images.
 -->

<animation-list xmlns:android="http://schemas.android.com/apk/res/android" 
    android:oneshot="false">
<item android:drawable="@drawable/loading_1_00000" android:duration="75" />
<item android:drawable="@drawable/loading_1_00002" android:duration="75" />
<item android:drawable="@drawable/loading_1_00004" android:duration="75" />
<item android:drawable="@drawable/loading_1_00006" android:duration="75" />
<item android:drawable="@drawable/loading_1_00008" android:duration="75" />
<item android:drawable="@drawable/loading_1_00010" android:duration="75" />

<item android:drawable="@drawable/loading_1_00012" android:duration="75" />
<item android:drawable="@drawable/loading_1_00014" android:duration="75" />
<item android:drawable="@drawable/loading_1_00016" android:duration="75" />
<item android:drawable="@drawable/loading_1_00018" android:duration="75" />
<item android:drawable="@drawable/loading_1_00020" android:duration="75" />
<item android:drawable="@drawable/loading_1_00022" android:duration="75" />

<item android:drawable="@drawable/loading_1_00024" android:duration="75" />
<item android:drawable="@drawable/loading_1_00026" android:duration="75" />
<item android:drawable="@drawable/loading_1_00028" android:duration="75" />
<item android:drawable="@drawable/loading_1_00030" android:duration="75" />
<item android:drawable="@drawable/loading_1_00032" android:duration="75" />
<item android:drawable="@drawable/loading_1_00034" android:duration="75" />

<item android:drawable="@drawable/loading_1_00036" android:duration="75" />
<item android:drawable="@drawable/loading_1_00038" android:duration="75" />
<item android:drawable="@drawable/loading_1_00040" android:duration="75" />
<item android:drawable="@drawable/loading_1_00042" android:duration="75" />
<item android:drawable="@drawable/loading_1_00044" android:duration="75" />
<item android:drawable="@drawable/loading_1_00046" android:duration="75" />

<item android:drawable="@drawable/loading_1_00048" android:duration="75" />
<item android:drawable="@drawable/loading_1_00050" android:duration="75" />
<item android:drawable="@drawable/loading_1_00052" android:duration="75" />

</animation-list>

爪哇代码：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    // Inflate the layout to use as dialog or embedded fragment
    view = inflater.inflate(R.layout.dialog_loading, container, false);

    //Get the ImageView 
    ImageView img1 = (ImageView) view.findViewById(R.id.iv_loading);
    //set the animation as the background of the ImageView
    //the animation is described in /res/anim/frame_animation.xml

    img1.setBackgroundResource(R.anim.frame_animation);

    img1.setBackgroundColor(0);   // <---- get error here

    //create an instance of AnimationLoop
    AnimationLoop animLoop = new AnimationLoop(img1);

    //create a timer
    Timer t = new Timer(false);
    //schedule the animation loop
    t.schedule(animLoop, 100);

    return view;
}

//our animation handler
class AnimationLoop extends TimerTask
{
    ImageView img1;
    AnimationLoop(ImageView im)
    {
        img1 = im;
    }

    public void run()
    {
        // Get the background, which has been compiled to an AnimationDrawable object.
        AnimationDrawable frameAnimation1 = (AnimationDrawable) img1.getBackground();

        // Start the animation (looped play back by default).
        frameAnimation1.start();
    }
}

错误：

06-07 12:04:39.450: E/AndroidRuntime(6581): FATAL EXCEPTION: Timer-1
06-07 12:04:39.450: E/AndroidRuntime(6581): java.lang.ClassCastException: android.graphics.drawable.ColorDrawable cannot be cast to android.graphics.drawable.AnimationDrawable
06-07 12:04:39.450: E/AndroidRuntime(6581):     at za.co.domain.client.product.tools.ProgressDialogFragment$AnimationLoop.run(ProgressDialogFragment.java:79)
06-07 12:04:39.450: E/AndroidRuntime(6581):     at java.util.Timer$TimerImpl.run(Timer.java:284)

编辑：

看截图 从当 android:background="#0000" 建议：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#0000" >
    <FrameLayout
        android:layout_width="@dimen/dialog_width"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:background="#0000" >        
        <ImageView
            android:id="@+id/iv_loading"
            android:layout_width="@dimen/dialog_width"
            android:layout_height="wrap_content"
            android:scaleType="fitCenter"
            android:adjustViewBounds="true"
            android:background="#0000" />        
    </FrameLayout>
</LinearLayout>

Answer 1

尝试设置

android:background="@null"

在您的 中，从您的 中FrameLayout删除该行。android:background="@android:color/transparent"imageView

更新

您还可以尝试添加以下内容：

AnimationDrawable drawable = (AnimationDrawable)res.getDrawable(R.R.anim.frame_animation);
img1.setBackgroundDrawable(drawable);