public class Loading_view extends ProgressDialog {
  public Loading_view(Context context) {
    super(context);
  }
  public Loading_view(Context context, int theme) {
    super(context, theme);
  }
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    init(getContext());
  }
  private void init(Context context) {
    setCancelable(true);
    setCanceledOnTouchOutside(false);
    setContentView(R.layout.loading);//loading的xml文件
    WindowManager.LayoutParams params = getWindow().getAttributes();
    params.width = WindowManager.LayoutParams.WRAP_CONTENT;
    params.height = WindowManager.LayoutParams.WRAP_CONTENT;
    getWindow().setAttributes(params);
  }
  @Override
  public void show() {//开启
    super.show();
  }
  @Override
  public void dismiss() {//关闭
    super.dismiss();
  }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="100dp"
  android:layout_height="100dp"
  android:layout_gravity="center_horizontal"
  android:background="@drawable/shape_dialog_bg"//背景色
  android:layout_centerInParent="true"
  android:orientation="vertical">
  <RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp">
    <ProgressBar
      android:id="@+id/pb_load"
      android:layout_width="65dp"
      android:layout_height="65dp"
      android:indeterminateDrawable="@drawable/progressbar"//加载圈的样式
      android:layout_centerInParent="true"/>
  </RelativeLayout>
  <TextView
    android:id="@+id/tv_load_dialog"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="加载中..."
    android:textColor="#9a9b98"
    android:textSize="12sp"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
  <corners android:radius="8dp" />
  <solid android:color="#88000000" />
</shape>

<animated-rotate
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:pivotX="50%" android:pivotY="50%"
  android:fromDegrees="0"
  android:toDegrees="720">
  <shape
    android:shape="ring"
    android:innerRadiusRatio="3"
    android:thicknessRatio="15"
    android:useLevel="false">
    <gradient
      android:type="sweep"
      android:useLevel="false"
      android:startColor="#55c6c6c6"
      android:centerColor="#c6c6c6"
      android:centerY="0.50"
      android:endColor="#c6c6c6" />
  </shape>
</animated-rotate>

public class MainActivity extends AppCompatActivity {
  private Loading_view loading;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }
  public void loding(View v){//点击加载并按钮模仿网络请求
    loading = new Loading_view(this,R.style.CustomDialog);
    loading.show();
    new Handler().postDelayed(new Runnable() {//定义延时任务模仿网络请求
      @Override
      public void run() {
    loading.dismiss();//3秒后调用关闭加载的方法
      }
    }, 3000);
  }
}

<style name="CustomDialog" parent="Theme.AppCompat.Dialog">
  <item name="android:backgroundDimEnabled">false</item>
  <item name="android:windowBackground">@android:color/transparent</item>
</style>