我正在 Android Studio 中开发一个项目，我应该使用 Wifi-Direct 连接两个设备。
我已成功通过 Wifi-direct 连接到另一台设备。我的问题是，当我在手机上手动关闭应用程序时，设备不会断开连接。我怎样才能实现这个目标？我对 Android Studio 和 java 还很陌生。
这是我的 WifiDirectActivity 类:
public class WiFiDirectActivity extends Activity implements WifiP2pManager.ChannelListener, DeviceListFragment.DeviceActionListener {
public static final String TAG = "wifidirectdemo";
private WifiP2pManager manager;
private boolean isWifiP2pEnabled = false;
private boolean retryChannel = false;
private final IntentFilter intentFilter = new IntentFilter();
private WifiP2pManager.Channel channel;
private BroadcastReceiver receiver = null;
/**
* @param isWifiP2pEnabled the isWifiP2pEnabled to set
*/
public void setIsWifiP2pEnabled(boolean isWifiP2pEnabled) {
this.isWifiP2pEnabled = isWifiP2pEnabled;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_peers);
// add necessary intent values to be matched.
intentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
manager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
channel = manager.initialize(this, getMainLooper(), null);
}
/** register the BroadcastReceiver with the intent values to be matched */
@Override
public void onResume() {
super.onResume();
receiver = new WiFiDirectBroadcastReceiver(manager, channel, this);
registerReceiver(receiver, intentFilter);
if (!amConnected) {
performSearch();
}
}
@Override
public void onPause() {
super.onPause();
unregisterReceiver(receiver);
}
/**
* Remove all peers and clear all fields. This is called on
* BroadcastReceiver receiving a state change event.
*/
public void resetData() {
DeviceListFragment fragmentList = (DeviceListFragment) getFragmentManager()
.findFragmentById(R.id.frag_list);
DeviceDetailFragment fragmentDetails = (DeviceDetailFragment) getFragmentManager()
.findFragmentById(R.id.frag_detail);
if (fragmentList != null) {
fragmentList.clearPeers();
}
if (fragmentDetails != null) {
fragmentDetails.resetViews();
}
}
@Override
public void showDetails(WifiP2pDevice device) {
DeviceDetailFragment fragment = (DeviceDetailFragment) getFragmentManager()
.findFragmentById(R.id.frag_detail);
fragment.showDetails(device);
}
@Override
public void connect(WifiP2pConfig config) {
manager.connect(channel, config, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
// WiFiDirectBroadcastReceiver will notify us. Ignore for now.
}
@Override
public void onFailure(int reason) {
Toast.makeText(WiFiDirectActivity.this, "Connect failed. Retry.",
Toast.LENGTH_SHORT).show();
}
});
}
@Override
public void disconnect() {
final DeviceDetailFragment fragment = (DeviceDetailFragment) getFragmentManager()
.findFragmentById(R.id.frag_detail);
fragment.resetViews();
manager.removeGroup(channel, new WifiP2pManager.ActionListener() {
@Override
public void onFailure(int reasonCode) {
Log.d(TAG, "Disconnect failed. Reason :" + reasonCode);
}
@Override
public void onSuccess() {
fragment.getView().setVisibility(View.GONE);
}
});
}
@Override
public void onChannelDisconnected() {
// we will try once more
if (manager != null && !retryChannel) {
Toast.makeText(this, "Channel lost. Trying again", Toast.LENGTH_LONG).show();
resetData();
retryChannel = true;
manager.initialize(this, getMainLooper(), this);
} else {
Toast.makeText(this,
"Severe! Channel is probably lost premanently. Try Disable/Re-Enable P2P.",
Toast.LENGTH_LONG).show();
}
}
@Override
public void cancelDisconnect() {
/*
* A cancel abort request by user. Disconnect i.e. removeGroup if
* already connected. Else, request WifiP2pManager to abort the ongoing
* request
*/
if (manager != null) {
final DeviceListFragment fragment = (DeviceListFragment) getFragmentManager()
.findFragmentById(R.id.frag_list);
if (fragment.getDevice() == null
|| fragment.getDevice().status == WifiP2pDevice.CONNECTED) {
disconnect();
} else if (fragment.getDevice().status == WifiP2pDevice.AVAILABLE
|| fragment.getDevice().status == WifiP2pDevice.INVITED) {
manager.cancelConnect(channel, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
Toast.makeText(WiFiDirectActivity.this, "Aborting connection",
Toast.LENGTH_SHORT).show();
}
@Override
public void onFailure(int reasonCode) {
Toast.makeText(WiFiDirectActivity.this,
"Connect abort request failed. Reason Code: " + reasonCode,
Toast.LENGTH_SHORT).show();
}
});
}
}
}
private void performSearch() {
final DeviceListFragment fragment = (DeviceListFragment) getFragmentManager()
.findFragmentById(R.id.frag_list);
fragment.onInitiateDiscovery();
manager.discoverPeers(channel, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
Toast.makeText(WiFiDirectActivity.this, "Discovery Initiated",
Toast.LENGTH_SHORT).show();
}
@Override
public void onFailure(int reasonCode) {
Toast.makeText(WiFiDirectActivity.this, "Discovery Failed : " + reasonCode,
Toast.LENGTH_SHORT).show();
}
});
}
}
最佳答案
当您关闭应用程序时，执行将通过 onPause() 回调运行，您应该在此处调用 disconnect() 方法。不过，请花 5 分钟的时间来了解一下 Android 的生命周期原理:https://developer.android.com/guide/components/activities/activity-lifecycle.html 。这是开发 Android 应用之前首先要学习的事情之一。
关于java - 关闭应用程序时如何断开与设备的连接？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43187292/