如何检查Android中的HDMI设备连接状态？

Question

我需要检测HDMI设备是否已连接到我的Android设备.为此,我正在使用BroadcastReceiver,它也能够检测到.但是使用BroadcastReceiver,即使在我的应用程序启动之前,我也无法处理连接HDMI设备的情况.在这种情况下,BroadcastReceiver无法找到是否连接了任何HDMI设备.有什么方法可以让我知道是否有任何HDMI设备连接？

Answer 1

我使用其他答案和其他地方的答案提出了这个问题:

/**
 * Checks device switch files to see if an HDMI device/MHL device is plugged in, returning true if so.
 */
private boolean isHdmiSwitchSet() {

    // The file '/sys/devices/virtual/switch/hdmi/state' holds an int -- if it's 1 then an HDMI device is connected.
    // An alternative file to check is '/sys/class/switch/hdmi/state' which exists instead on certain devices.
    File switchFile = new File("/sys/devices/virtual/switch/hdmi/state");
    if (!switchFile.exists()) {
        switchFile = new File("/sys/class/switch/hdmi/state");
    }
    try {
        Scanner switchFileScanner = new Scanner(switchFile);
        int switchValue = switchFileScanner.nextInt();
        switchFileScanner.close();
        return switchValue > 0;
    } catch (Exception e) {
        return false;
    }
}

如果您经常进行检查,则需要存储结果并使用@ hamen的监听器进行更新.

Answer 2

我最终出来了.它正在使用S3和S4.它应该适用于任何4+ Android版本.

public class HdmiListener extends BroadcastReceiver {

    private static String HDMIINTENT = "android.intent.action.HDMI_PLUGGED";

    @Override
    public void onReceive(Context ctxt, Intent receivedIt) {
        String action = receivedIt.getAction();

        if (action.equals(HDMIINTENT)) {
            boolean state = receivedIt.getBooleanExtra("state", false);

            if (state) {
                Log.d("HDMIListner", "BroadcastReceiver.onReceive() : Connected HDMI-TV");
                Toast.makeText(ctxt, "HDMI >>", Toast.LENGTH_LONG).show();    
            } else {
                Log.d("HDMIListner", "HDMI >>: Disconnected HDMI-TV");
                Toast.makeText(ctxt, "HDMI DisConnected>>", Toast.LENGTH_LONG).show();
            }
        }
    }
}

AndroidManifest.xml需要将其转换为应用程序标记:

    <receiver android:name="__com.example.android__.HdmiListener" >
        <intent-filter>
            <action android:name="android.intent.action.HDMI_PLUGGED" />
        </intent-filter>
    </receiver>

Answer 3

您可以从/sys/class/display/display0.hdmi/connect. 如果文件内容为0，则未连接 HDMI，否则为1，则连接 HDMI。

try {
    File file = new File("/sys/class/display/display0.hdmi/connect");
    InputStream in = new FileInputStream(file);
    byte[] re = new byte[32768];
    int read = 0;
    while ((read = in.read(re, 0, 32768)) != -1) {
        String string = new String(re, 0, read);
        Log.v("String_whilecondition", "HDMI state = " + string);
        result = string;
    }
    in.close();
} catch (IOException ex) {
    ex.printStackTrace();
}