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[英]How can I go to the next activity instead of previous activity after scanning QR code
[英]ANDROID How can I send result in a new Activity after scanning a QR Code?
大家好,我正在嘗試創建一個掃描QR碼的應用。
在主要活動中,我想掃描QR碼,然后將結果發送到新的活動中。
這是我的代碼
主要Activity.java:
public class MainActivity extends AppCompatActivity {
SurfaceView cameraView;
BarcodeDetector barcode;
CameraSource cameraSource;
SurfaceHolder holder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.CAMERA}, 200);
}
cameraView = (SurfaceView) findViewById(R.id.cameraView);
cameraView.setZOrderMediaOverlay(true);
holder = cameraView.getHolder();
barcode = new BarcodeDetector.Builder(this)
.setBarcodeFormats(Barcode.QR_CODE)
.build();
if(!barcode.isOperational()){
Toast.makeText(getApplicationContext(), "Sorry, Couldn't setup the detector", Toast.LENGTH_LONG).show();
this.finish();
}
cameraSource = new CameraSource.Builder(this, barcode)
.setFacing(CameraSource.CAMERA_FACING_BACK)
.setRequestedFps(24)
.setAutoFocusEnabled(true)
.setRequestedPreviewSize(1920,1024)
.build();
cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) {
try{
if(ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED){
cameraSource.start(cameraView.getHolder());
}
}
catch (IOException e){
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
});
barcode.setProcessor(new Detector.Processor<Barcode>() {
@Override
public void release() {
}
@Override
public void receiveDetections(Detector.Detections<Barcode> detections) {
final SparseArray<Barcode> barcodes = detections.getDetectedItems();
if(barcodes.size() > 0){
Intent intent = new Intent(MainActivity.this, Result.class);
startActivityForResult(intent, 100);
intent.putExtra("barcode", barcodes.valueAt(0));
setResult(RESULT_OK, intent);
finish();
}
}
});
}}
Result.java:
public class Result extends AppCompatActivity {
TextView result;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
result = (TextView) findViewById(R.id.result);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode == 100 && resultCode == RESULT_OK){
if(data != null){
final Barcode barcode = data.getParcelableExtra("barcode");
result.post(new Runnable() {
@Override
public void run() {
result.setText(barcode.displayValue);
}
});
}
}
}}
但是,當我嘗試在結果活動中測試應用程序時,我看不到結果。
怎么了?
謝謝大家
在Result活動中,數據的檢索應在onCreate方法中,而不是在onActivityResult中,您的Result類應如下所示:
public class Result extends AppCompatActivity {
TextView result;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
result = (TextView) findViewById(R.id.result);
final Barcode barcode = getIntent().getParcelableExtra("barcode");
result.setText(barcode.displayValue);
}
}
在MainActivity中,此行:
intent.putExtra("barcode", barcodes.valueAt(0));
應該在之前
startActivityForResult(intent, 100);
不像這樣:
Intent intent = new Intent(MainActivity.this, Result.class);
intent.putExtra("barcode", barcodes.valueAt(0));
startActivityForResult(intent, 100);
finish();
僅當您要返回啟動活動以及被調用活動的結果時,才使用startActivityForResult
。 在您的情況下,只需調用startActivity
啟動結果活動,然后使用getIntent
獲取結果活動中的數據。
您在MainActivity中編寫的代碼
Intent intent = new Intent(MainActivity.this, Result.class);
startActivityForResult(intent, 100);
intent.putExtra("barcode", barcodes.valueAt(0));
setResult(RESULT_OK, intent);
finish();
是錯誤的實際上應該如下所示,請不要ActivityForResult
Intent intent = new Intent(MainActivity.this, Result.class);
intent.putExtra("barcode", barcodes.valueAt(0));
startActivityForResult(intent, 100);
finish();
為了在ResultActivity onCreate()方法中從MainActivity獲取結果,請使用以下代碼(如果要顯示結果)
TextView YourResult
YourResult = (TextView) findViewById(R.id.TextView_YourResult);
final Barcode barcode = getIntent().getParcelableExtra("barcode");
result.setText(barcode.displayValue);
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