[英]onCreate being called twice causing app to exit prematurely
我浏览了其他 SO 帖子,但没有找到与我的问题相关的任何内容。
我正在尝试创建一个应用程序,该应用程序将从上次重新启动时获取用户的步数。 这是我的主要活动:
package com.assignment.bwowassignment;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.app.AppCompatDelegate;
import java.util.Arrays;
public class MainActivity extends AppCompatActivity implements MainActivityContract.View {
MainActivityPresenter presenter;
@RequiresApi(api = Build.VERSION_CODES.Q)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
Log.d("mihir", "hello");
presenter = new MainActivityPresenter(this);
presenter.requestActivityPermission(this);
}
@Override
public void onGetStepsSuccess(float[] values) {
Log.d("mihir", Arrays.toString(values));
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == presenter.ACTIVITY_REQUEST_CODE)
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
presenter.registerListener(this);
else {
Log.d("mihir", "kill me");
finish();
}
}
@Override
protected void onPause() {
super.onPause();
presenter.sensorManager.unregisterListener(presenter);
}
}
MainActivityPresenter.java
package com.assignment.bwowassignment;
import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Build;
import android.util.Log;
import androidx.annotation.RequiresApi;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import java.util.logging.Logger;
public class MainActivityPresenter implements MainActivityContract.Presenter, SensorEventListener {
MainActivityContract.View view;
SensorManager sensorManager;
Sensor sensor;
public MainActivityPresenter(MainActivityContract.View view) {
this.view = view;
sensorManager = (SensorManager) ((Context) view).getSystemService(Context.SENSOR_SERVICE);
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
}
@Override
public void registerListener(Context context) {
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);
}
@RequiresApi(api = Build.VERSION_CODES.Q)
@Override
public void requestActivityPermission(Context context) {
if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACTIVITY_RECOGNITION) == PackageManager.PERMISSION_GRANTED)
registerListener(context);
else if (ActivityCompat.shouldShowRequestPermissionRationale((Activity) context, Manifest.permission.ACTIVITY_RECOGNITION))
new AlertDialog.Builder(context)
.setTitle("Permission required")
.setMessage("This permission is required to fetch the sensor data from your phone, denying it will cause the app to exit")
.setPositiveButton("Give permission", (dialog, which) -> ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.ACTIVITY_RECOGNITION}, ACTIVITY_REQUEST_CODE))
.setNegativeButton("Deny", (dialog, which) -> ((Activity) context).finish())
.show();
else
ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.ACTIVITY_RECOGNITION}, ACTIVITY_REQUEST_CODE);
}
@Override
public void onSensorChanged(SensorEvent event) {
view.onGetStepsSuccess(event.values);
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}
MainActivityContract.java
package com.assignment.bwowassignment;
import android.content.Context;
public interface MainActivityContract {
interface View {
void onGetStepsSuccess(float[] values);
}
interface Presenter {
int ACTIVITY_REQUEST_CODE = 1;
void registerListener(Context context);
void requestActivityPermission(Context context);
}
}
如您所见,标签中有两个我的名字的日志,这里发生的是“hello”日志被记录了两次。 我猜这是第一个 onCreate ,它负责我的应用程序在开始之前完成,因为我在 logcat 中收到此警告:
W/Activity: Can request only one set of permissions at a time
我只请求一个权限,但由于 onCreate 被调用了两次,第一个权限被自动拒绝,这导致应用程序在它已经启动之前finish()
,从昨天开始我一直在摸不着头脑,感谢任何帮助!
我想到了!
罪魁祸首是这一行: AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
显然,这会导致配置更改,导致onCreate
方法被调用两次,为了克服这个问题,在调用 super in onCreate 之前调用它,如下所示:
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
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