1、自定义对话框
public class HKDialogLoading extends Dialog {
	Context context;

	public HKDialogLoading(Context context, int theme) {
		super(context, theme);
		this.context = context;
		ini();
	}

	public HKDialogLoading(Context context) {
		super(context);
		this.context = context;
		ini();
	}

	void ini() {
		/**
		 * "加载项"布局，此布局被添加到ListView的Footer中。
		 */
		LinearLayout contentView = new LinearLayout(context);
		contentView.setMinimumHeight(60);
		contentView.setGravity(Gravity.CENTER);
		contentView.setOrientation(LinearLayout.HORIZONTAL);

		/**
		 * 向"加载项"布局中添加一个圆型进度条。
		 */
		ImageView image = new ImageView(context);
		image.setImageResource(R.drawable.loading_icon);
		Animation anim = AnimationUtils.loadAnimation(context,
				R.anim.rotate_repeat);
		LinearInterpolator lir = new LinearInterpolator();
		anim.setInterpolator(lir);
		image.setAnimation(anim);

		contentView.addView(image);
		setContentView(contentView);

	}

	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		// 按下键盘上返回按钮
		if (keyCode == KeyEvent.KEYCODE_BACK) {
			this.dismiss();
		}
		return true;
	}
}


2、用到的动画文件rotate_repeat
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/accelerate_interpolator" >
    <rotate
        android:duration="1000"
        android:fromDegrees="0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:repeatCount="100"
        android:repeatMode="restart"
        android:toDegrees="360" />
</set>

3、用的到的样式文件
    <style name="HKDialog" parent="@android:style/Theme.Dialog">
        <item name="android:windowFrame">@null</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowBackground">@color/transparent</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:windowContentOverlay">@null</item>
    </style>

4、调用
dialogLoading = new HKDialogLoading(this, R.style.HKDialog);
dialogLoading.show(); // 显示加载中对话框