从活动到片段的多个结果

问题描述

我有一个关于从活动到片段的结果/回调的问题。 到目前为止,我有一个片段,它调用相机活动来扫描QR码。因此,我以startActivityForResult从片段开始活动。如果成功扫描QR码,我将收到Intent中处理的回调onActivityResult。 效果很好。

现在,我想处理多个扫描。详细而言,这意味着每次成功扫描都应调用onActivityResult函数而不关闭活动。我现在遇到的问题是,只有在相机活动中调用onActivityResult时才会调用finish()

所以我的问题是,如何在调用onActivityResult或不调用finish()的情况下多次调用class ScanFragment : Fragment() { private val CHECKIN_CODE = 0 private val CHECKOUT_CODE = 1 companion object { fun newInstance(): LeadScanFragment = LeadScanFragment() } override fun onCreateView(inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?): View? { val view = inflater.inflate(R.layout.fragment_lead_scan,container,false) view.checkin.setOnClickListener {view -> val intent = Intent(activity,CodeScannerActivity::class.java) startActivityForResult(intent,CHECKIN_CODE) } view.checkout.setOnClickListener {view -> val intent = Intent(activity,CHECKOUT_CODE) } return view } override fun onActivityResult(requestCode: Int,resultCode: Int,data: Intent?) { super.onActivityResult(requestCode,resultCode,data) if (requestCode == CHECKIN_CODE) { if (resultCode == Activity.RESULT_OK) { val returnString = data!!.getStringExtra("hash") Log.d("scaned in",returnString) } } if (requestCode == CHECKOUT_CODE) { if (resultCode == Activity.RESULT_OK) { val returnString = data!!.getStringExtra("hash") Log.d("scaned out",returnString) } } } } 而又不关闭活动?还是有另一种方法来处理从活动到片段的回调?

这是我的片段代码:

class CodeScannerActivity : AppCompatActivity() {

    private val requestCodeCameraPermission = 1001
    private lateinit var cameraSource: CameraSource
    private lateinit var detector: BarcodeDetector

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_code_scanner)

        if (ContextCompat.checkSelfPermission(this@CodeScannerActivity,Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            askForCameraPermission()
        } else {
            setup()
        }
    }

    private fun setup() {
        detector = BarcodeDetector.Builder(this@CodeScannerActivity).build()
        cameraSource = CameraSource.Builder(this@CodeScannerActivity,detector).setAutoFocusEnabled(true).build()

        cameraSurfaceView.holder.addCallback(surfaceCallback)
        detector.setProcessor(processor)
    }

    private fun askForCameraPermission() {
        ActivityCompat.requestPermissions(this@CodeScannerActivity,arrayOf(Manifest.permission.CAMERA),requestCodeCameraPermission)
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,permissions: Array<out String>,grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode,permissions,grantResults)

        if(requestCode == requestCodeCameraPermission && grantResults.isNotEmpty()) {
            if(grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                setup()
            } else {
                Toast.makeText(applicationContext,"Permission denied!",Toast.LENGTH_SHORT).show()
            }
        }
    }

    private val surfaceCallback = object : SurfaceHolder.Callback {
        override fun surfaceCreated(surfaceHolder: SurfaceHolder?) {
            try {
                cameraSource.start(surfaceHolder)
            } catch (exception: Exception) {
                Toast.makeText(applicationContext,"Something went wrong",Toast.LENGTH_SHORT).show()
            }
        }

        override fun surfaceChanged(p0: SurfaceHolder?,p1: Int,p2: Int,p3: Int) {

        }

        override fun surfaceDestroyed(p0: SurfaceHolder?) {
            cameraSource.stop()
        }
    }

    private val processor = object : Detector.Processor<Barcode> {
        override fun release() {

        }

        override fun receiveDetections(detections: Detector.Detections<Barcode>?) {
            val intent = Intent()

            if(detections != null && detections.detectedItems.isNotEmpty()) {
                val qrCodes: SparseArray<Barcode> = detections.detectedItems
                val code = qrCodes.valueAt(0)

                intent.putExtra("hash",code.displayValue)
                setResult(Activity.RESULT_OK,intent)
                finish()
            } else {
                setResult(Activity.RESULT_CANCELED,intent)
                finish()
            }
        }
    }
}

这是相机活动代码:

receiveDetections
摄像机活动代码下部processor内的

onActivityResult是将回调Intent发送回import React from 'react'; import SetTimer from './components/SetTimer'; import './App.css'; class App extends React.Component { state = { breakCount: 5,sessionCount: 25,clockCount: 25 * 60,currentTimer: 'Session',isPlaying: false,}; constructor(props) { super(props); this.loop = undefined; this.handlePlayPause = this.handlePlayPause.bind(this); } componentWillUnmount() { clearInterval(this.loop); } handlePlayPause() { const { isPlaying } = this.state; console.log(isPlaying); if (isPlaying) { //if the time is playing and we press this button,then we need to puase or clear the playing intervals clearInterval(this.loop); this.setState({ isPlaying: false }); } else { this.setState({ isPlaying: true }); this.loop = setInterval(() => { const { clockCount,breakCount,sessionCount,currentTimer,} = this.state; if (clockCount === 0) { this.setState({ currentTimer: currentTimer === 'Session' ? 'Break' : 'Session',clockCount: currentTimer === 'Session' ? breakCount * 60 : sessionCount * 60,}); } else { this.setState({ clockCount: clockCount - 1 }); } },1000); } } handleReset = () => { this.setState({ breakCount: 5,}); clearInterval(this.loop); }; convertTime = (count) => { const minutes = Math.floor(count / 60); let seconds = count % 60; seconds = seconds < 10 ? `0${seconds}` : `${seconds}`; return `${minutes}:${seconds}`; }; handleBreakDecrease = () => { const { breakCount } = this.state; if (breakCount >= 2) { this.setState({ breakCount: breakCount - 1 }); } }; handleBreakIncrease = () => { const { breakCount } = this.state; this.setState({ breakCount: breakCount + 1 }); }; handleSessionDecrease = () => { const { sessionCount } = this.state; if (sessionCount >= 2) { this.setState({ sessionCount: sessionCount - 1,clockCount: (sessionCount - 1) * 60,}); } }; handleSessionIncrease = () => { const { sessionCount } = this.state; this.setState({ sessionCount: sessionCount + 1,}); }; render() { const { breakCount,clockCount,currentTimer } = this.state; const breakProps = { title: 'Break Length',count: breakCount,handleDecrease: this.handleBreakDecrease,handleIncrease: this.handleBreakIncrease,}; const sessionProps = { title: 'Session Length',count: sessionCount,handleDecrease: this.handleSessionDecrease,handleIncrease: this.handleSessionIncrease,}; return ( <div> <div className='flex'> <SetTimer {...breakProps} /> <SetTimer {...sessionProps} /> </div> <div className='clock-container'> <h1>{currentTimer}</h1> <span>{this.convertTime(clockCount)}</span> <div className='flex'> <button onClick={this.handlePlayPause}> {this.state.isPlaying ? ( <i className={`fas fa-pause`}></i> ) : ( <i className='fas fa-play'></i> )} </button> <button onClick={this.handleReset}> <i className='fas fa-sync-alt'></i> </button> </div> </div> </div> ); } } export default App; 的地方。

解决方法

您可以让扫描器Activity发送本地广播Intent,以将“结果”转发给呼叫方FragmentFragment(或其托管Activity)应设置一个侦听器以侦听广播的“结果”。这样,您可以执行多次扫描并将每个结果发送回基础Activity

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