java如何解决在安卓的父或祖先上下文中找不到方法:onClick属性?
我试图在用户单击按钮时启动前台服务和通知。此按钮被称为“startBtn”。它旨在显示用户所采取的步骤数
我有3个文件,StepsFragment。java,片段和步骤。xml和StepsService。爪哇
当用户单击按钮时,我在Logcat中遇到此错误:
java.lang.IllegalStateException: Could not find method startService(View) in a parent or ancestor Context for 安卓:onClick attribute defined on view class 安卓.support.v7.widget.AppCompatButton with id 'startBtn'
我在StackOverflow上尝试了以下解决方案:
Could not find method in a parent or ancestor Context for 安卓:onClick attribute
这是我在StepsFragment中的代码。爪哇:
package sg.edu.singaporetech.teamproject;
import 安卓.content.Context;
import 安卓.content.Intent;
import 安卓.hardware.Sensor;
import 安卓.hardware.SensorEvent;
import 安卓.hardware.SensorEventListener;
import 安卓.hardware.SensorManager;
import 安卓.os.Bundle;
import 安卓.support.annotation.Nullable;
import 安卓.support.v4.app.Fragment;
import 安卓.view.LayoutInflater;
import 安卓.view.View;
import 安卓.view.ViewGroup;
import 安卓.widget.Button;
import 安卓.widget.ProgressBar;
import 安卓.widget.TextView;
import 安卓.widget.Toast;
public class StepsFragment extends Fragment implements SensorEventListener, View.OnClickListener {
Button updateBtn;
ProgressBar progressBar;
TextView tv_steps;
TextView levelDisplay;
SensorManager sensorManager;
Sensor sensor;
boolean running = false;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_steps, container, false);
super.onCreate ( savedInstanceState );
updateBtn = view.findViewById(R.id.updateBtn);
progressBar = view.findViewById(R.id.progress_bar);
tv_steps = (TextView) view.findViewById(R.id.tv_steps);
levelDisplay = (TextView) view.findViewById(R.id.levelDisplay);
sensorManager = (SensorManager) getActivity().getSystemService ( Context.SENSOR_SERVICE);
updateBtn.setOnClickListener(this);
return view;
}
public void startService(View view) {
String input = tv_steps.getText().toString();
Intent serviceIntent = new Intent(getActivity(),StepsService.class);
serviceIntent.putExtra("inputExtra",input);
getActivity().startService(serviceIntent);
}
}
这是片段_步骤中的按钮代码。xml:
<安卓.support.v7.widget.AppCompatButton
安卓:id="@+id/startBtn"
style="?安卓:attr/borderlessButtonStyle"
安卓:layout_width="match_parent"
安卓:layout_height="wrap_content"
安卓:layout_marginTop="30dp"
安卓:background="@drawable/btn_orange"
安卓:text="@string/start_steps"
安卓:textColor="@color/white"
安卓:textSize="15dp"
安卓:onClick="startService"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@+id/updateBtn" />
最后,这是StepsService中的代码。爪哇
package sg.edu.singaporetech.teamproject;
import 安卓.app.Notification;
import 安卓.app.PendingIntent;
import 安卓.app.Service;
import 安卓.content.Intent;
import 安卓.os.IBinder;
import 安卓.support.annotation.Nullable;
import 安卓.support.v4.app.NotificationCompat;
import static sg.edu.singaporetech.teamproject.StepsNotification.CHANNEL_ID;
public class StepsService extends Service {
@Override
public void onCreate() {
super.onCreate();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
String input = intent.getStringExtra("inputExtra");
Intent notificationIntent = new Intent(this,StepsFragment.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this,0,notificationIntent,0);
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Steps Tracker")
.setContentText("Steps tracked")
.setSmallIcon(R.drawable.exersize)
.setContentIntent(pendingIntent)
.build();
startForeground(1,notification);
return START_NOT_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
# 1 楼答案
android:onClick="startService"
将不会在片段中调用。您应该使用OnClickListener
来处理此类事件另一种方法是在活动中声明
startService
函数,然后从活动中调用片段方法请参阅Android app crashing (fragment and xml onclick)了解更多信息