Android 无原因自动返回上一个活动屏幕
我有一个活动叫做Android 无原因自动返回上一个活动屏幕,android,kotlin,firebase-realtime-database,Android,Kotlin,Firebase Realtime Database,我有一个活动叫做LoanActivity。我从MapsActivity转到这个活动。但是，在LoanActivity上运行几秒钟后，它会返回到MapsActivity，而我什么也不做。我需要修复它，但我不确定它为什么会发生 我正在尝试更新以下数据库： Locker对象使其在此处不可用（其唯一id已从MapsActivity传递到此处） 将储物柜的名称、纬度和经度添加到数据库中的Loan对象中 我正在复制下面的代码： class LoanActivity : AppCompatActivity()
LoanActivityLoanActivityMapsActivityMapsActivityclass LoanActivity : AppCompatActivity() {
private lateinit var locationsText: EditText //to show locker name
private lateinit var Results: EditText //to show locker address
private lateinit var loanLogoutButton: Button
private lateinit var firebaseDatabase: FirebaseDatabase
var aTool: Tool? =null
var thelocker: Locker?=null
var lockerName = "XXX"
var lockerAddress = "YYY"
var id: String? = ""
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_loan)
firebaseDatabase = FirebaseDatabase.getInstance()
locationsText = findViewById(R.id.locationsText)
Results = findViewById(R.id.Results)
loanLogoutButton= findViewById(R.id.loanLogoutButton)
loanLogoutButton.isEnabled
val intent = getIntent()
//grab the data passed from MapsActivity
//id of the loan, use this to find other details of it from the database
id = intent?.getStringExtra("IDofLI")
//name of the locker is unique, get other details from the database
val nameOfLocker = intent.getStringExtra("MARKERTITLE")
val lockerLT = intent.getDoubleExtra("MARKERLT", 0.0)
val lockerLG = intent.getDoubleExtra("MARKERLG", 0.0)
doAsync {
//Find the locker with id, and make it unavailable
//We will put this loaned item in it
val reference = firebaseDatabase.getReference("Locker")
val addValueEventListener =
reference.addValueEventListener(object : ValueEventListener {
override fun onCancelled(error: DatabaseError) {
Log.d("LoanA", "3:onCreate")
runOnUiThread {
Toast.makeText(
this@LoanActivity,
"Failed to reach database: $error!",
Toast.LENGTH_LONG
).show()
}
}
override fun onDataChange(data: DataSnapshot) {
data.children.forEach { child ->
val locker = child.getValue(Locker::class.java)
if (locker != null && locker.name == nameOfLocker) {
//This is how you update the database entry
var dr = reference.child(child.key.toString())
//Create a brand new locker, same as old one, but set available field to 0
thelocker = Locker(
locker.name,
locker.day,
locker.month,
locker.year,
0,
locker.zip,
locker.address,
locker.RenterEmail,
locker.LoanerEmail,
locker.rOrl, //rent or loan
locker.lat,
locker.longt
)
lockerAddress = locker.address
lockerName = locker.name
dr.setValue(thelocker)
locationsText.setText(lockerName)
Results.setText(lockerAddress)
}
}
}
})
//Find the Loan item with id
//Update it in the database to have the lockerName
val reference2 = firebaseDatabase.getReference("Tool/Loan")
val addValueEventListener2 =
reference2.addValueEventListener(object : ValueEventListener {
override fun onCancelled(error: DatabaseError) {
runOnUiThread {
Toast.makeText(
this@LoanActivity,
"Failed to reach database: $error!",
Toast.LENGTH_LONG
).show()
}
}
override fun onDataChange(data: DataSnapshot) {
data.children.forEach { child ->
val tool = child.getValue(Tool::class.java)
if (tool != null && child.key.toString() == id) {
Log.d(
"TOOL_FOUND*",
"Item being loaned is updated in DB: id=" + child.key
)
//This is how you update the database entry
var dr = reference2.child(child.key.toString())
//create a brand new tool, same as old one, but set lockerName
aTool = Tool(
tool.day,
tool.month,
tool.year,
tool.type,
tool.available,
tool.zip,
tool.host,
tool.guest,
tool.rOrl, //rent or loan
nameOfLocker,
lockerLT,
lockerLG,
tool.price
)
dr.setValue(aTool)
}
}
Log.d("LoanA", "11")
}
})
Log.d("LoanA", "12")
}
loanLogoutButton.setOnClickListener {
Log.d("LoanA", "13")
//send the id of this restaurant to the next screen for reviews
val intent2 = Intent(this@LoanActivity, MainActivity::class.java)
startActivity(intent2)
}
}
}
logcat中没有例外： 我有这个： 2020-02-11 22:35:30.211 10084-10127/android.bignerdranch.project1d/EGL_仿真：eglMakeCurrent:0xe0a85600:ver 3 0（tinfo 0xe0a833d0） 2020-02-11 22:35:30.221 10084-10542/android.bignerdranch.project1d/EGL_仿真：eglCreateContext:0xc436c980:maj 1 min 0 rcv 1 2020-02-11 22:35:31.055 10084-10542/android.bignerdranch.project1d/EGL\u仿真：eglMakeCurrent:0xc436c980:Ver10（tinfo 0xc5fa8210） 2020-02-11 22:35:31.086 10084-10084/android.bignerdranch.project1我/编舞：跳过了56帧！应用程序可能在其主线程上做了太多工作。 2020-02-11 22:35:31.097 10084-10127/android.bignerdranch.project1 I/OpenGLRenderer:Davey！持续时间=948ms；Flags=0，IntentendedVsync=31654948913988，Vsync=31655882247284，OldestInputEvent=9223372036854775807，NewestInputEvent=0，HandleInputStart=31655888412820，AnimationStart=31655888480620，PerformTraversalsStart=31655888514520，DrawStart=316558858120，SyncQueued=31655888793620，SyncStart=31655890131720，IssueDrawCommandsStart=31655890241220，SwapBuffers=31655893764920，FrameCompleted=31655899112020，DequeueBufferDuration=817000，QueueBufferDuration=1703000， 2020-02-11 22:35:36.905 10084-10084/android.bignerdranch.project1 E/SchedPolicy:set\u timerslock\n写入失败：不允许操作 2020-02-11 22:35:36.917 10084-10127/android.bignerdranch.project1d/EGL_仿真：eglMakeCurrent:0xe0a85600:ver 3 0（tinfo 0xe0a833d0） 2020-02-11 22:36:00.230 10084-10542/android.bignerdranch.project1d/EGL\u仿真：eglMakeCurrent:0xc436c980:Ver10（tinfo 0xc5fa8210） 2020-02-11 22:36:01.110 10084-10084/android.bignerdranch.project1 E/SchedPolicy:set\u timerslock\n写入失败：不允许操作
2020-02-11 22:36:01.157 10084-10127/android.bignerdranch.project1d/EGL_仿真：eglMakeCurrent:0xe0a85600:ver 3 0（tinfo 0xe0a833d0）似乎你的应用程序在
LoanActivityMapsActivityMapsActivity希望这能对您有所帮助。日志中没有例外：我有这个：2020-02-11 22:35:30.211 10084-10127/android.bignerdranch.project1 D/EGL_仿真：eglMakeCurrent:0xe0a85600:ver 3 0（tinfo 0xe0a833d0）2020-02-11 22:35:30.221 10084-10542/android.bignerdranch.project1 D/EGL_仿真：eglCreateContext:0xc436c980:maj 1 min 0 rcv 1 2020-02-11 22:35:31.055 10084-10542/android.bignerdranch.project1 D/EGL_仿真：eglmakeccurrent:0xc436c980:ver1 0（tinfo 0xc5fa8210）2020-02-11 22:35:31.086 10084-10084/android.bignerdranch.project1我/编舞：跳过了56帧！应用程序可能在其主线程上做了太多工作。2020-02-11 22:35:31.097 10084-10127/android.bignerdranch.project1 I/OpenGLRenderer:Davey
Logcat显示您正在UI线程上执行一些繁重的任务，这就是应用程序崩溃的原因。您在Logcat中看到任何异常吗？在某些设备上，应用程序在崩溃时不会关闭，它会重新启动。logcat中没有异常：我添加了logcat，没有异常。我如何打破这个循环？重写数据更改（数据：DataSnapshot）{data.children.forEach{child->val工具=child.getValue（工具：：class.java）