java - 我正在开发一个简单的计步器应用程序，它有这些错误，代码如下

Question

package com.example.ritwik.letswalk;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements SensorEventListener{


    TextView tv_steps;

    SensorManager sensorManager;
    boolean running=false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    tv_steps=(TextView) findViewById(r.id.tv_steps);
    sensorManager=(SensorManager) getSystemService(Context.SENSOR_SERVICE);
    }
    @Override
    protected void onResume()
    {
        super.onResume();
        running=true;
        Sensor countSensor=sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
        if(countSensor==null){
            sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
        }
        else
            Toast.makeText(this, "Sensor Not Found",Toast.LENGTH_SHORT).show();
    }
    @Override
    protected void onPause()
    {
        super.onPause();
        running=false;
    }
    @Override
    protected void onSensorChangeed(SensorEvent event)
    {
        if(running)
        {
            tv_steps.setText(String.valueOf(event.values[0]));
        }
    }
}

代码有以下错误

Error:(21, 15) error: cannot find symbol class TextView Error:Execution failed for task ':app:compileDebugJavaWithJavac'. Compilation failed; see the compiler error output for details. Error:(12, 5) error: cannot find symbol class TextView Error:(43, 37) error: cannot find symbol class SensorEvent Error:(11, 8) error: MainActivity is not abstract and does not override abstract method onAccuracyChanged(Sensor,int) in SensorEventListener Error:(21, 39) error: package r does not exist Error:(42, 5) error: method does not override or implement a method from a supertype

Answer 1

SensorEventListener 有两个抽象方法:

1) onAccuracyChanged(传感器传感器, int 精度)2)onSensorChanged(SensorEvent事件)

您还需要重写 onAccuracyChanged 方法。

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

    }

当传感器的精度发生变化时，会调用此方法。如果您不想在这里做任何事情，那么就不要在这里编写任何代码。但由于它是抽象的，因此您需要实现它。

希望有帮助。