包頭華為云代理商：AndROId監聽(tīng)狀態(tài)

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Android監聽(tīng)狀態(tài)

在A(yíng)ndroid開(kāi)發(fā)中，我們經(jīng)常需要監聽(tīng)一些系統或者應用的狀態(tài)，比如網(wǎng)絡(luò )狀態(tài)、電池狀態(tài)、應用啟動(dòng)和關(guān)閉等等。下面是一些常用的狀態(tài)監聽(tīng)方式：

網(wǎng)絡(luò )狀態(tài)監聽(tīng)

Android中可以通過(guò)注冊BroadcastReceiver的方式來(lái)監聽(tīng)網(wǎng)絡(luò )狀態(tài)變化，具體可以參考下面的代碼：

  
private BroadcastReceiver mNetworkStateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
            //網(wǎng)絡(luò )狀態(tài)發(fā)生變化
            NetworkInfo info = intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
            if (info != null && info.isConnected()) {
                //網(wǎng)絡(luò )已連接
            } else {
                //網(wǎng)絡(luò )未連接
            }
        }
    }
};

// 注冊網(wǎng)絡(luò )狀態(tài)監聽(tīng)器
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(mNetworkStateReceiver, filter);
  
  

電池狀態(tài)監聽(tīng)

同樣的，Android中可以通過(guò)注冊BroadcastReceiver的方式來(lái)監聽(tīng)電池狀態(tài)變化，具體可以參考下面的代碼：

  
private BroadcastReceiver mBatteryStateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())) {
            //獲取電池狀態(tài)和電量信息
            int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
            int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100);
            int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, BatteryManager.BATTERY_STATUS_UNKNOWN);
            switch (status) {
                case BatteryManager.BATTERY_STATUS_CHARGING:
                    //正在充電
                    break;
                case BatteryManager.BATTERY_STATUS_DISCHARGING:
                    //正在放電
                    break;
                case BatteryManager.BATTERY_STATUS_FULL:
                    //充滿(mǎn)電
                    break;
                case BatteryManager.BATTERY_STATUS_NOT_CHARGING:
                    //未充電
                    break;
                default:
                    //未知狀態(tài)
                    break;
            }
        }
    }
};

// 注冊電池狀態(tài)監聽(tīng)器
IntentFilter filter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
registerReceiver(mBatteryStateReceiver, filter);
  
  

應用啟動(dòng)和關(guān)閉監聽(tīng)

Android中可以通過(guò)注冊ActivityLifecycleCallbacks的方式來(lái)監聽(tīng)應用啟動(dòng)和關(guān)閉事件，具體可以參考下面的代碼：

  
public class Myapplication extends Application {
    private boolean mIsForeground = false;
    
    @Override
    public void onCreate() {
        super.onCreate();
        
        registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
                //應用創(chuàng  )建
            }

            @Override
            public void onActivityStarted(Activity activity) {
                //應用啟動(dòng)
                mIsForeground = true;
            }

            @Override
            public void onActivityResumed(Activity activity) {
                //應用恢復
            }

            @Override
            public void onActivityPaused(Activity activity) {
                //應用暫停
            }

            @Override
            public void onActivityStopped(Activity activity) {
                //應用停止
                mIsForeground = false;
            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
                //應用保存狀態(tài)
            }

            @Override
            public void onActivityDestroyed(Activity activity) {
                //應用銷(xiāo)毀
            }
        });
    }
    
    public boolean isForeground() {
        return mIsForeground;
    }
}

// 在需要判斷應用是否在前臺的地方調用
if (getApplicationContext() instanceof MyApplication) {
    if (((MyApplication) getApplicationContext()).isForeground()) {
        //應用在前臺
    } else {
        //應用在后臺
    }
}
  
  

總結

Android狀態(tài)監聽(tīng)是開(kāi)發(fā)中經(jīng)常會(huì )用到的技術(shù)，通過(guò)適當的注冊BroadcastReceiver或者ActivityLifecycleCallbacks，可以輕松地監聽(tīng)系統或者應用的狀態(tài)變化，提升應用的用戶(hù)體驗。