无法在震动事件侦听器中解析getApplicationContext和startActivity方法：Android Studio [英] Unable to resolve getApplicationContext and startActivity methods in shake event listener: Android Studio

问题描述

我正在尝试实现一个震动事件监听器，下面是我的代码。如果需要的话，它是Android Studio环境。只是说无法解析方法getApplicationContext甚至startActivity。谁能帮我发现我的错误？

I am trying to implement a shake event listener and below is my code. It is Android Studio environment if it matters. It just says cannot resolve method getApplicationContext or even startActivity. Can anyone help me find my mistake?

package com.shaivaldesai.shake;

import android.app.Application;
import android.content.Context;
import android.content.Intent;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;

/**
 * Created by Shaival Desai on 7/3/14.
 */
public class ShakeEventListener implements SensorEventListener {


    @Override
    public void onAccuracyChanged(Sensor sensor, int i) {

    }

    // Low pass filter
    private float calcMaxAcceleration(SensorEvent sensorEvent) {

        final float alpha = 0.8f;

        float[] gravity = {-9.81f};

        gravity[0] = alpha * gravity[0] + (1 - alpha) * sensorEvent.values[0];
        gravity[1] = alpha * gravity[1] + (1 - alpha) * sensorEvent.values[1];
        gravity[2] = alpha * gravity[2] + (1 - alpha) * sensorEvent.values[2];

        float accX = sensorEvent.values[0] - gravity[0];
        float accY = sensorEvent.values[1] - gravity[1];
        float accZ = sensorEvent.values[2] - gravity[2];

        float max1 = Math.max(accX, accY);
        return Math.max(max1, accZ);
    }

    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
        //handleShake(sensorEvent);}
    float maxAcc = calcMaxAcceleration(sensorEvent);
       // void handleShake(sensorEvent){
        //float maxAcc = calcMaxAcceleration(sensorEvent);
        if(maxAcc>=15) {

        Intent intent = new Intent(getApplicationContext(),Main.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }
    }
}

推荐答案

SensorEventListener 中不存在这些方法。您必须从扩展 Activity 的类中复制了此内容。您需要在 Context 对象上调用这些方法。您应该在 ShakeEventListener 上定义一个自定义构造函数，该构造函数采用 Context 对象：

Those methods don't exist in SensorEventListener. You must have copied this from a class that extends Activity. You'll need to call these methods on a Context object. You should define a custom constructor on your ShakeEventListener that takes a Context object:

public class ShakeEventListener implements SensorEventListener {
    private Context mContext;

    public ShakeEventListener(Context context) {
        mContext = context;
    }

    /** omitting unchanged methods **/

    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
        //handleShake(sensorEvent);}
        float maxAcc = calcMaxAcceleration(sensorEvent);
        // void handleShake(sensorEvent){
        //float maxAcc = calcMaxAcceleration(sensorEvent);
        if(maxAcc>=15) {

            Intent intent = new Intent(mContext, Main.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            mContext.startActivity(intent);
        }
    }
}

这篇关于无法在震动事件侦听器中解析getApplicationContext和startActivity方法：Android Studio的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！