注：软件使用 fragment + RadioGroup 切换页面，未加载任何依赖包

效果

2020-06-06-115755-0.gif

实现步骤

第一步 增加base_loading.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/id_loading_and_retry"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:orientation="horizontal"
    android:gravity="center"
    tools:context=".MainActivity">

    <ProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        
        android:layout_margin="16dp"/>

    <TextView
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:text="正在加载中..."
        android:textSize="16sp"
        android:layout_marginLeft="10dp"/>

</LinearLayout>

第二步 MainActivity.java

主要是 messagevoid(); showLoadingDialog(); dismissLoadingDialog(); 这三个方法

public class MainActivity extends Activity{ 

    private static final String TAG = "MainActivity";
    private ArrayList<Fragment> fragmentList = new ArrayList<>();
    private RadioGroup radioGroup;
    private FragmentManager fragmentManager;
    
    private RadioButton rbrb1=null;
    private RadioButton rbrb2=null;
    private RadioButton rbrb3=null;
    private RadioButton rbrb4=null;
    private RadioButton rbrb5=null;

    private AlertDialog alertDialog;
    //==============================================
    //==============================================
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        initEvent();
    }
    
    //==============================================
    //==============================================
        /**
         * 标签栏 切换事件
         * 监听RadioGroup 改变
         */
        private void initEvent() {
            radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
                    @Override
                    public void onCheckedChanged(RadioGroup group, int checkedId) {

                        switch (checkedId) {
                            case R.id.radiobutton_home: {
                                    setCurrentFragment(0);
                                    break;
                                }
                            case R.id.radiobutton_message: {
                                    //打开加载窗口
                                    messagevoid();
                                    setCurrentFragment(1);
                                    break;
                                }
                            case R.id.radiobutton_discover: {
                                    setCurrentFragment(2);
                                    break;
                                }
                            case R.id.radiobutton_profile: {
                                    setCurrentFragment(3);
                                    break;
                                }
                            case R.id.radiobutton_post:{

                                    break;
                                }
                            default: {
                                }
                        }
                    }
                });
        }

    /**
     * 利用线程打开加载中窗口
     */
    private void messagevoid()
    {
        new Thread() {
            public void run() {
                Looper.prepare();
                
                showLoadingDialog();
                
                Looper.loop();
            };
        }.start();
    }
    
    /**
     * 展示加载中窗口
     */
    public void showLoadingDialog() {
        alertDialog = new AlertDialog.Builder(this).create();
        alertDialog.setCancelable(false);
        alertDialog.setOnKeyListener(new DialogInterface.OnKeyListener() {
                @Override
                public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
                    if (keyCode == KeyEvent.KEYCODE_SEARCH || keyCode == KeyEvent.KEYCODE_BACK)
                        return true;
                    return false;
                }
            });
        alertDialog.show();
        alertDialog.setContentView(R.layout.base_loading);
        alertDialog.setCanceledOnTouchOutside(false);
    }

    /**
     * 在fragment里调用这个，关闭加载中弹窗
     * 关闭
     */
    public void dismissLoadingDialog() {
        if (null != alertDialog && alertDialog.isShowing()) {
            alertDialog.dismiss();
        }
    }

        /**
         * 显示fragment
         * @param index
         */
        private void setCurrentFragment(int index){
            ......
        }

    ......

第三步 MessageFragment.java

((MainActivity)getActivity()).dismissLoadingDialog();

public class MessageFragment extends Fragment {

    ......

    @Override
    public void onStart() {
        super.onStart();
        ((MainActivity)getActivity()).dismissLoadingDialog();
    }

    ......

参考资料

• Android最简单的LoadingDialog - 简书