我正在尝试遵循手册（其中有一些错误并已修复）但是我收到此错误btstart cannot be resolved or is not a field并且我不知道如何修复它。这是该手册的链接（但我已经对布局和字符串 xml 文件进行了更改）这是 MainActivity.java 代码：
package com.example.stopwatch;
//import com.example.stopwatch.R;
import android.R;
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Chronometer;
public class MainActivity extends Activity implements OnClickListener {
private Button start;
private Button stop;
private Button reset;
private Chronometer mydChronometer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
uI();
}
public void uI() {
start = (Button) findViewById(R.id.btstart);
start.setOnClickListener(this);
stop = (Button) findViewById(R.id.btstop);
stop.setOnClickListener(this);
reset = (Button) findViewById(R.id.btreset);
reset.setOnClickListener(this);
mydChronometer = (Chronometer) findViewById(R.id.chronometer1);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onClick(View v) {
if (v == start) {
mydChronometer.start();
} else if (v == stop) {
mydChronometer.stop();
} else if (v== reset) {
mydChronometer.setBase(SystemClock.elapsedRealtime());
}
}
}
这是我的“activity_main.xml”：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/chronometer1"
android:layout_centerHorizontal="true"
android:layout_marginTop="67dp"
android:src="@drawable/myd" />
<Chronometer
android:id="@+id/chronometer1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="28dp"
android:gravity="center"
android:text="Chronometer"
android:textSize="35dp" />
<Button
android:id="@+id/btstart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView1"
android:layout_below="@+id/chronometer1"
android:layout_marginTop="18dp"
android:text="@string/start" />
<Button
android:id="@+id/btreset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btstop"
android:layout_alignBottom="@+id/btstop"
android:layout_toRightOf="@+id/btstop"
android:text="@string/reset" />
<Button
android:id="@+id/btstop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/btstart"
android:layout_alignBottom="@+id/btstart"
android:layout_toRightOf="@+id/btstart"
android:text="@string/stop" />
</RelativeLayout>
这是“strings.xml”文件：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">stopwatch</string>
<string name="btn1">Start</string>
<string name="btn2">Stop</string>
<string name="btn3">Reset</string>
<string name="menu_settings">Settings</string>
<string name="action_settings">Settings</string>
</resources>
我没有对 main.xml 进行任何更改，这是我的 main.xml：
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/action_settings"
android:orderInCategory="100"
android:showAsAction="never"
android:title="@string/action_settings"/>
</menu>
您能否让我知道我缺少什么以及此错误的解决方法是什么？
PS：我收到这些行的类似错误：
btstop cannot be resolved or is not a field in stop = (Button) findViewById(R.id.btstop);
btreset cannot be resolved or is not a field in reset = (Button) findViewById(R.id.btreset);
chronometer1 cannot be resolved or is not a field in mydChronometer = (Chronometer) findViewById(R.id.chronometer1);
万分感谢。