预期的类或接口
我曾经使用eclipse与android sdk，但我刚刚下载了android studio。 我想使用加速度计，但由于某种原因，我不断得到相同的问题。“预期类或接口”我附上下面的代码，如果有人能给我一个问题的解决方案，我将被迫。
package com.example.symbox.myapplication; import android.app.Activity; import android.content.Context; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.ImageView; import android.widget.TextView; public class MainActivity extends ActionBarActivity implements SensorEventListener { private float mLastX, mLastY, mLastZ; private boolean mInitialized; private SensorManager mSensorManager; private Sensor mAccelerometer; private final float NOISE = (float) 2.0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mInitialized = false; mSensorManager = (SensorManager) getSystemService(Context.SEARCH_SERVICE); mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL); } } protected void onResume(){ super.onResume(); mSensorManager.registerListener(this,mAccelerometer,SensorManager.SENSOR_DELAY_NORMAL); } protected void onPause(){ super.onPause(); mSensorManager.unregisterListener(this); } public void onAccuracyChanged(Sensor sensor,int accuracy){ } public void onSensorChanged(SensorEvent event){ TextView tvX= (TextView)findViewById(R.id.x_axis); TextView tvY= (TextView)findViewById(R.id.y_axis); TextView tvZ= (TextView)findViewById(R.id.z_axis); ImageView iv = (ImageView)findViewById(R.id.image); float x = event.values[0]; float y = event.values[1]; float z = event.values[2]; if(!mInitialized){ mLastX = x; mLastY = y; mLastZ = z ; tvX.setText("0.0"); tvY.setText("0.0"); tvZ.setText("0.0"); mInitialized = true; } else { float deltaX = Math.abs(mLastX - x); float deltaY = Math.abs(mLastY - y); float deltaZ = Math.abs(mLastZ - z); if (deltaX < NOISE) deltaX = (float)0.0; if (deltaY < NOISE) deltaY = (float)0.0; if (deltaZ deltaY) { iv.setImageResource(R.drawable.horizontal); } else if (deltaY > deltaX) { iv.setImageResource(R.drawable.vertical); } else { iv.setVisibility(View.INVISIBLE); } } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } 由于“预期的类或接口”错误，这些是我一直看到的日志
C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:38: error: class, interface, or enum expected public boolean onCreateOptionsMenu(Menu menu) { ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:41: error: class, interface, or enum expected return true; ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:42: error: class, interface, or enum expected } ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:45: error: class, interface, or enum expected public boolean onOptionsItemSelected(MenuItem item) { ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:52: error: class, interface, or enum expected if (id == R.id.action_settings) { ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:54: error: class, interface, or enum expected } ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:57: error: class, interface, or enum expected } ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:60: error: class, interface, or enum expected public void onSensorChanged(SensorEvent event) { ^ C:\Users\Abeer\AndroidStudioProjects\test_one\app\src\main\java\com\example\symbox\test_one\MainActivity.java:65: error: class, interface, or enum expected public void onAccuracyChanged(Sensor sensor, int accuracy) {
你不小心关闭了你的课程，额外的“}”：
public class MainActivity extends ActionBarActivity implements SensorEventListener { private float mLastX, mLastY, mLastZ; ... mSensorManager = (SensorManager) getSystemService(Context.SEARCH_SERVICE); mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL); } } // Delete this line!