一般的android应用都会监听手机网络变化，根据网络是否连接或者网络环境进行相应的操作或者限制。这里写下自己的实现方式。

效果.png

步骤：

• 自定义接收网络变化的广播接收器，接收到网络变化时通过EventBus发出通知
• 在所有activity的基类BaseActivity中注册自定义的广播接收器
• 在BaseActivity中接收EventBus的网络变化通知，来进行对话框形式的提示信息

1.自定义接收网络变化的广播接收器,在配置文件中添加权限 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

/**
 * Created by dingmouren on 2018/8/1.
 * 监听网络状态变更的广播接收器
 */

public class NetworkConnectChangedReceiver extends BroadcastReceiver{

    private static final String TAG = "NetworkChangedReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
       
        if (intent.getAction() == ConnectivityManager.CONNECTIVITY_ACTION) {
            /*判断当前网络时候可用以及网络类型*/
            boolean isConnected = NetworkUtils.isConnected();
            NetworkUtils.NetworkType networkType = NetworkUtils.getNetworkType();
            EventBus.getDefault().post(new NetworkChangeEvent(isConnected, networkType));
        }
    }
}

2.BaseActivity注册网络状态变化的广播接收器，并实现相应的UI提示。每一个activity可见的时候，这里都会在onResume中去检查网络是否连接，再者就是每当监听网络变化的广播接收器发出通知时，处理显示或者隐藏提示对话框。

/**
 * Created by dingmouren on 2018/3/19.
 * emial: naildingmouren@gmail.com
 */

public abstract class BaseActivity extends AppCompatActivity{

    private static final String TAG = "BaseActivity";

    protected Context mContext;

    protected boolean mCheckNetwork = true;/*默认检查网络状态*/

    protected boolean mNetConnected;/*网络连接的状态，true表示有网络，flase表示无网络连接*/

    private NetworkConnectChangedReceiver mNetWorkChangReceiver;/*网络状态变化的广播接收器*/

    private NetStateChangedDialog mNetStateChangedDialog;/*网络状态变化的提示对话框*/

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mContext = this;

        EventBus.getDefault().register(this);

        mNetStateChangedDialog = new NetStateChangedDialog(this);

        //注册网络状态监听广播
        mNetWorkChangReceiver = new NetworkConnectChangedReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
        registerReceiver(mNetWorkChangReceiver, filter);
    }

    @Override
    protected void onResume() {
        super.onResume();
        netStateChangedUI(NetworkUtils.isConnected());
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(mNetWorkChangReceiver);
        EventBus.getDefault().unregister(this);
    }

    /**
     * 网络状态发生变化时的处理
     * @param event
     */
    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onNetworkChangeEvent(NetworkChangeEvent event){

        Log.i(TAG,"网络发生变化:"+event.toString());

        mNetConnected = event.isConnected();
    
        netStateChangedUI(event.isConnected());
       
    }

    /**
     * 根据网络状态显示或者隐藏提示对话框
     * @param isConnected
     */
    private void netStateChangedUI(boolean isConnected){
        if (mCheckNetwork) {
            if (isConnected) {
                if (null != mNetStateChangedDialog)mNetStateChangedDialog.dismiss();
            }else {
                if (null != mNetStateChangedDialog)mNetStateChangedDialog.show();
            }
        }
    }

    /**
     * 设置是否要检查网络状态变化
     * @param checkNetWork
     */
    public void setCheckNetWork(boolean checkNetWork) {
        mCheckNetwork = checkNetWork;
    }


}

自定义对话框的实现：
NetStateChangedDialog.java

/**
 * Created by dingmouren on 2018/8/2.
 */

public class NetStateChangedDialog extends Dialog {
    public NetStateChangedDialog(@NonNull Context context) {
        super(context, R.style.StyleNetChangedDialog);
        View contentView = LayoutInflater.from(context).inflate(R.layout.dialog_network_state_tip,null);

        initView(contentView);
        setContentView(contentView);

        setCanceledOnTouchOutside(false);

        WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
        layoutParams.width = WindowManager.LayoutParams.MATCH_PARENT;
        layoutParams.gravity = Gravity.TOP;
        layoutParams.windowAnimations = R.style.StyleNetChangedDialog_Animation;
        getWindow().setAttributes(layoutParams);
        getWindow().setDimAmount(0f);/*使用时设置窗口后面的暗淡量*/
    }

    private void initView(View contentView) {

    }


}

style.xml中的样式

  <style name="StyleNetChangedDialog" parent="@android:style/Theme.Dialog">
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowBackground">@android:color/transparent</item>
    </style>
    <style name="StyleNetChangedDialog.Animation" parent="Animation.AppCompat.Dialog">
        <item name="android:windowEnterAnimation">@anim/translate_netstate_dialog_in</item>
        <item name="android:windowExitAnimation">@anim/translate_netstate_dialog_out</item>
    </style>

anim的位移动画:
translate_netstate_dialog_in.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="0"
    android:fromYDelta="-100%"
    android:toXDelta="0"
    android:toYDelta="0">
</translate>

translate_netstate_dialog_out.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="300"
    android:fromXDelta="0"
    android:fromYDelta="0"
    android:toXDelta="0"
    android:toYDelta="-100%">
</translate>