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我已經創建了應用程序,它可以檢測otg電纜何時插入或何時使用fileobserver插入,但由於某種原因它不工作! 爲什麼應用程序無法正常工作?安卓文件觀察器
應用程序的源代碼:
MainActivity.class
public class MainActivity extends AppCompatActivity
{
private Process suProcess;
private static int conn_length = -1;
File directory = new File("/sys/bus/usb/devices");
File[] contents = directory.listFiles();
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getRoot();
FileObserver observer = new FileObserver("/sys/bus/usb/devices")
{
@Override
public void onEvent(int event, String file)
{
if(contents.length == conn_length){
return;
}
else{
conn_length = contents.length;
}
if(conn_length == 0)
{
Toast.makeText(MainActivity.this,"otg not connected",Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(MainActivity.this,"otg connected",Toast.LENGTH_SHORT).show();
}
}
};
observer.startWatching();
}
private void getRoot()
{
try
{
suProcess = Runtime.getRuntime().exec("su");
}
catch (IOException e)
{
}
}
}
我只想檢測OTG電纜沒有插在它上面的設備!!!!! – pavlenis1906