Android操作系统中默认的loading动画怎么调用

progressdialog先添加要加载xml面
始隐藏其组件
显示progressdialog
延迟段间再显示其组件隐藏progressdialog
// 图片数量
private int count =8;
//图片ID数组
private int[] ids={R.drawable.r1,R.drawable.r2,R.drawable.r3,R.drawable.r4,
R.drawable.r5,R.drawable.r6,R.drawable.r7,R.drawable.r8};

private Handler handler;
private ImageView img_loading;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.loading);
img_loading = (ImageView) this.findViewById(R.id.img_loading);
handler = new Handler(){
public void handleMessage(Message msg)
{
/**
* 更改ImageView图片
*/
img_loading.setImageDrawable(getDrawable(msg.what));
}
};
play();

}

/**
* 获取图片象
* @param id
* @return
*/
private Drawable getDrawable(int id)
{
return this.getResources().getDrawable(ids[id]);
}

/**
* 播放画
*/
private void play()
{

new Thread(){

@SuppressWarnings("static-access")
@Override
public void run()
{

while(true)
{
for (int i = 0; i < count; i++)
{
handler.sendEmptyMessage(i);
try
{
this.sleep(100);
} catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
}
}.start();
}

Android中Dialog的示例代码如下：
1.创建对象框
AlertDialog.Builder builder = new Builder(context);
builder.setTitle("请输入"); //设置对话框标题
builder.setIcon(android.R.drawable.btn_star); //设置对话框标题前的图标

2.创建EditText输入框
final EditText edit = new EditText(context);

3.将输入框赋值给Dialog,并增加确定取消按键
builder.setView(edit);
builder.setPositiveButton("确认", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(context, "你输入的是: " + edit.getText().toString(), Toast.LENGTH_SHORT).show();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(context, "你点了取消", Toast.LENGTH_SHORT).show();
}
});

4.设置常用api，并show弹出
builder.setCancelable(true); //设置按钮是否可以按返回键取消,false则不可以取消
AlertDialog dialog = builder.create(); //创建对话框
dialog.setCanceledOnTouchOutside(true); //设置弹出框失去焦点是否隐藏,即点击屏蔽其它地方是否隐藏
dialog.show();