Question

我正在使用以下方案开发应用程序：

Activity

我在每个Intent到Activity之间传递我的值，它可以正常工作，但当我回到Activity A时，似乎所有值都被清除了。

来自Intent client = new Intent(getApplicationContext(), ActivityA.class); client.putExtra("TOKEN_VALUE", TOKEN_VALUE); client.putExtra("PARAMS", params); // Hashmap with {"id":"value"} client.putExtra("PICLIST", picArray); client.putExtra("TESTLIST", testArray); client.putExtra("TESTDATA", myData); client.putExtra("TESTTEMP", myTemp); client.putExtra("COMPTEUR", compteur); client.putExtra("LAUNCH",first_launch); client.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); startActivity(client); C的代码：

null

当我尝试获取这些值时，它们都是onCreate()。

编辑：

以下是onNewIntent()和protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_home); // init the gps to get a location locationListener = new MyLocationListener(); locationMangaer = (LocationManager) getSystemService(Context.LOCATION_SERVICE); locationMangaer.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, locationListener); // Checking if Wifi is enabled final WifiManager wifi = (WifiManager) this.getSystemService(Context.WIFI_SERVICE); if (isSharingWiFi(wifi)) { new AlertDialog.Builder(this) .setCancelable(false) .setMessage("L' application requiert une connexion à Internet") .setPositiveButton("Accéder aux paramètres wifi ", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS)); } }) .setNegativeButton("Accéder aux paramètres du réseau mobile", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { startActivity(new Intent(Settings.ACTION_DATA_ROAMING_SETTINGS)); } }) .setIcon(android.R.drawable.ic_dialog_alert) .show().getWindow().setLayout(1000, 600); } mId = (EditText) findViewById(R.id.exam_valve); mName = (EditText) findViewById(R.id.exam_op); b1 = (Button) findViewById(R.id.take_picture); b2 = (Button) findViewById(R.id.add_exam_button); b3 = (Button) findViewById(R.id.addTest_button); b1.setOnClickListener(clickListenerBoutons); // Init and fill the two spinners condition_status = (Spinner) findViewById(R.id.spinner_valve_condition); reason_status = (Spinner) findViewById(R.id.spinner_exam_reason); ArrayAdapter<String> valve_condition_adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item) { @Override public View getView(int position, View convertView, ViewGroup parent) { return super.getView(position, convertView, parent); } }; valve_condition_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); valve_condition_adapter.add(getResources().getString(R.string.ok)); conditionArray[0] = "ok"; valve_condition_adapter.add(getResources().getString(R.string.rusty)); conditionArray[1] = "rusty"; valve_condition_adapter.add(getResources().getString(R.string.damaged)); conditionArray[2] = "damaged"; valve_condition_adapter.add(getResources().getString(R.string.broken)); conditionArray[3] = "broken"; condition_status.setAdapter(valve_condition_adapter); ArrayAdapter<String> exam_reason_adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item) { @Override public View getView(int position, View convertView, ViewGroup parent) { return super.getView(position, convertView, parent); } }; exam_reason_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); exam_reason_adapter.add(getResources().getString(R.string.programmed)); reasonArray[0] = "programmed"; exam_reason_adapter.add(getResources().getString(R.string.valve_installation)); reasonArray[1] = "valve-installation"; exam_reason_adapter.add(getResources().getString(R.string.improvised)); reasonArray[2] = "improvised"; reason_status.setAdapter(exam_reason_adapter); condition_status.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { condition = conditionArray[position]; } @Override public void onNothingSelected(AdapterView<?> parent) { } }); reason_status.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { reason = reasonArray[position]; } @Override public void onNothingSelected(AdapterView<?> parent) { } }); // Init the request queue mRequestQueue = Volley.newRequestQueue(getApplicationContext()); mRequestQueue.start(); // Creating the Token to connect to the REST server final String myUrl = MY_SERVER_ADDRESS; JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, myUrl, null, new Response.Listener<JSONObject>() { @Override public void onResponse(JSONObject jsonObject) { exponent = jsonObject.optString("publicExponent"); modulus = jsonObject.optString("publicModulus"); ex = new BigInteger(exponent); mo = new BigInteger(modulus); Log.i("TEST REST ", ex.toString()); Log.i("TEST REST ", mo.toString()); try { key = RSACrypt.encrypt("temporary password", mo, ex); Log.i("TOKEN GENERATION", "La clé est : " + key); HashMap<String, String> params = new HashMap<String, String>(); params.put("password", key); String body = new JSONObject(params).toString().replace("\\", ""); Log.i("JSON OBJECT", body); JsonRequest tokenRequest = new JsonStringRequest(Request.Method.POST, myUrl, body, new Response.Listener<JSONObject>() { @Override public void onResponse(JSONObject jsonObject) { TOKEN_VALUE = jsonObject.optString("token"); Log.i("TOKEN GENERATION", "Le token est : " + TOKEN_VALUE); } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) { String message = new String(volleyError.networkResponse.data); Log.i("REQUETE 2", "Erreur" + volleyError.getMessage() + message); } }); mRequestQueue.add(tokenRequest); } catch (Exception e) { e.printStackTrace(); Log.i("ERROR TOKEN GENERATION", e.getMessage()); } } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) { TOKEN_VALUE = "HOSTUNREACHABLE"; Log.i("REQUETE 1", "Erreur" + volleyError.getMessage()); } }); mRequestQueue.add(request); // Sending the request with all parameters b2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Getting the current date DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss"); String date = df.format(Calendar.getInstance().getTime()); lon = locationMangaer.getLastKnownLocation(LOCATION_SERVICE).getLongitude(); lat = locationMangaer.getLastKnownLocation(LOCATION_SERVICE).getLatitude(); // Filling params params.put(REASON, reason); params.put(ID_VALVE, mId.getText().toString()); params.put(OPERATOR, mName.getText().toString()); params.put(DATE, date + "T00:00:00"); params.put(CONDITION, condition); params.put(LONGITUDE, Double.toString(lon)); params.put(LATITUDE, Double.toString(lat)); for (int k = 0; k < pictureNameArray.length; k++) { Bitmap bm = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory() + "/MyApp/MyImages/" + pictureNameArray[k] + ".jpg"); ByteArrayOutputStream baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object byte[] b = baos.toByteArray(); String encodedImage = Base64.encodeToString(b, Base64.NO_WRAP); Log.i("PICTURE data", encodedImage); HashMap<String, String> currentPic = new HashMap<String, String>(); currentPic.put(DATA, encodedImage); currentPic.put(FILENAME, pictureNameArray[k]); currentPic.put(MEDIATYPE, "image/jpg"); PicList.put(new JSONObject(currentPic)); } AlertDialog.Builder alert = new AlertDialog.Builder(HomeActivity.this); final EditText edittext = new EditText(getApplicationContext()); alert.setMessage("Veuillez saisir un commentaire sur l'examen"); alert.setTitle("Commentaire"); alert.setView(edittext); alert.setPositiveButton("Continuer", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { String myComment = edittext.getText().toString(); params.put(COMMENT, myComment); if (TOKEN_VALUE == "HOSTUNREACHABLE") { // Save on SQL Lite + alert } else { Intent intent = new Intent(HomeActivity.this, SendMyRequestService.class); intent.putExtra("PARAMS", params); intent.putExtra("PICLIST", pictureNameArray); intent.putExtra("TESTLIST", TestList.toString()); startActivity(intent); } } }); alert.setNegativeButton("Annuler", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { params.clear(); } }); alert.show(); } }); b3.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { params.put(REASON, reason); params.put(ID_VALVE, mId.getText().toString()); params.put(OPERATOR, mName.getText().toString()); params.put(CONDITION, condition); Intent intent = new Intent(HomeActivity.this, ListDeviceActivity.class); intent.putExtra("COMPTEUR", pictureNumber); intent.putExtra("TOKEN_VALUE", TOKEN_VALUE); intent.putExtra("PARAMS", params); intent.putExtra("PICLIST", pictureNameArray); intent.putExtra("TESTLIST", TestList.toString()); startActivity(intent); } }); @Override protected void onNewIntent(Intent intent) { super.onNewIntent(intent); String TOKEN_VALUE = intent.getStringExtra("TOKEN_VALUE"); String params = intent.getStringExtra("params"); String test_data = intent.getStringExtra("TESTDATA"); String test_temp = intent.getStringExtra("TESTTEMP"); String testArray = intent.getStringExtra("TESTLIST"); try { JSONObject parameters = new JSONObject(params); Log.i("Id valve récuperé", parameters.optString("ID_VALVE")); Log.i("Raison récuperée", parameters.optString("REASON")); Log.i("Nom opérateur récuperé", parameters.optString("OPERATOR")); Log.i("Condition récuperée", parameters.optString("CONDITION")); if (parameters.optString("ID_VALVE") != null) mId.setText(parameters.optString("ID_VALVE")); if (parameters.optString("REASON") != null) { int i = this.getResources().getIdentifier(parameters.optString("REASON"), "string", this.getPackageName()); reason_status.setSelection(i); } if (parameters.optString("OPERATOR") != null) mName.setText(parameters.optString("OPERATOR")); if (parameters.optString("CONDITION") != null) { int j = this.getResources().getIdentifier(parameters.optString("CONDITION"), "string", this.getPackageName()); condition_status.setSelection(j); } } catch (JSONException e) { e.printStackTrace(); } if (intent.getStringArrayExtra("PICLIST") != null) { pictureNameArray = intent.getStringArrayExtra("PICLIST"); } HashMap<String, String> currentTest = new HashMap<String, String>(); if (testArray != null) { try { TestList = new JSONArray(testArray); currentTest.put(TDATA, test_data); currentTest.put(TEMP, test_temp); TestList.put(new JSONObject(currentTest)); } catch (JSONException e) { e.printStackTrace(); } } else { currentTest.put(TDATA, test_data); currentTest.put(TEMP, test_temp); TestList.put(new JSONObject(currentTest)); } }的代码：

input

Answer 1

卸下：

client.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

在ActivityA中使用：

   @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
       if (resultCode == Activity.RESULT_OK && data != null) {
     //do some action
    }

 }

Answer 2

使用FLAG_ACTIVITY_SINGLE_TOP时，您可以使用Intent方法检索onNewIntent()，而不是onCreate().

@Override
protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    String TOKEN_VALUE = intent.getStringExtra("TOKEN_VALUE");
    String params = intent.getStringExtra("params");
    // and so on ....
}

对于singleTop活动，onNewIntent()方法充当执行的入口点，而不是onCreate()。由于Activity已存在于某处，因此不会调用onCreate()。

此外，在这种情况下使用startActivityForResult()，因为其他一些帖子建议是错误的。对onActivityResult()的回调将在C中，而不在A中。

Answer 3

在活动C中用代码替换你的代码：

Intent i = new Intent(ActivityC.this, ActivityA.class);
i.putExtra("TOKEN_VALUE", TOKEN_VALUE);
i.putExtra("PARAMS", params);
startActivity(i);

在活动A中，只需按以下方式获取值：

Intent intent= getIntent();
String value1 = intent.getStringExtra("TOKEN_VALUE");
String value2 = intent.getStringExtra("params");

Android - 当Activity设置为Single Top时无法检索Intent

3 个答案: