所以我几个星期前把这个项目放在一边，它运作得很好。我今天早些时候对其中一个活动进行了一些更改，将其加载到模拟器中，并在进入我的菜单屏幕（splash - ＆gt; menu - ＆gt; new activities）后死亡。因此，在两次崩溃之后，我尝试了不同的活动。一个工作。返回...点击另一个未被触及的，繁荣。强制关闭/崩溃。我没有更改菜单java或XML文件中的任何内容，也没有更改清单。
世界上有什么可能造成这种情况？ Eclipse中没有错误，我认为没有改变任何错误，导致它执行此操作。
日志附件：
08-14 14:34:45.301: W/KeyCharacterMap(343): No keyboard for id 0
08-14 14:34:45.301: W/KeyCharacterMap(343): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
08-14 14:35:40.461: D/AndroidRuntime(343): Shutting down VM
08-14 14:35:40.471: W/dalvikvm(343): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
08-14 14:35:40.491: E/AndroidRuntime(343): FATAL EXCEPTION: main
08-14 14:35:40.491: E/AndroidRuntime(343): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.tomcat.performance/com.tomcat.performance.TireTemps}: java.lang.NullPointerException
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.os.Handler.dispatchMessage(Handler.java:99)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.os.Looper.loop(Looper.java:123)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-14 14:35:40.491: E/AndroidRuntime(343): at java.lang.reflect.Method.invokeNative(Native Method)
08-14 14:35:40.491: E/AndroidRuntime(343): at java.lang.reflect.Method.invoke(Method.java:521)
08-14 14:35:40.491: E/AndroidRuntime(343): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-14 14:35:40.491: E/AndroidRuntime(343): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-14 14:35:40.491: E/AndroidRuntime(343): at dalvik.system.NativeStart.main(Native Method)
08-14 14:35:40.491: E/AndroidRuntime(343): Caused by: java.lang.NullPointerException
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.Activity.findViewById(Activity.java:1637)
08-14 14:35:40.491: E/AndroidRuntime(343): at com.tomcat.performance.TireTemps.<init>(TireTemps.java:25)
08-14 14:35:40.491: E/AndroidRuntime(343): at java.lang.Class.newInstanceImpl(Native Method)
08-14 14:35:40.491: E/AndroidRuntime(343): at java.lang.Class.newInstance(Class.java:1429)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
08-14 14:35:40.491: E/AndroidRuntime(343): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
08-14 14:35:40.491: E/AndroidRuntime(343): ... 11 more
TIRETEMPS.JAVA
package com.tomcat.performance;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
package com.tomcat.performance;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class TireTemps extends Activity implements OnClickListener {
EditText tempLFouterString = ((EditText) findViewById(R.id.tempLFouter)),
tempLFmiddleString = ((EditText) findViewById(R.id.tempLFmiddle)),
tempLFinnerString = ((EditText) findViewById(R.id.tempLFinner)),
tempRFinnerString = ((EditText) findViewById(R.id.tempRFinner)),
tempRFmiddleString = ((EditText) findViewById(R.id.tempRFmiddle)),
tempRFouterString = ((EditText) findViewById(R.id.tempRFouter)),
tempRRinnerString = ((EditText) findViewById(R.id.tempRRinner)),
tempRRmiddleString = ((EditText) findViewById(R.id.tempRRmiddle)),
tempRRouterString = ((EditText) findViewById(R.id.tempRRouter)),
tempLRouterString = ((EditText) findViewById(R.id.tempLRouter)),
tempLRmiddleString = ((EditText) findViewById(R.id.tempLRmiddle)),
tempLRinnerString = ((EditText) findViewById(R.id.tempLRinner));
TextView tempNoseAverageString = ((TextView) findViewById(R.id.tempNoseAverage)),
tempLFaverageString = ((TextView) findViewById(R.id.tempLFaverage)),
tempRFaverageString = ((TextView) findViewById(R.id.tempRFaverage)),
tempLRaverageString = ((TextView) findViewById(R.id.tempLRaverage)),
tempRRaverageString = ((TextView) findViewById(R.id.tempRRaverage)),
tempRearAverageString = ((TextView) findViewById(R.id.tempRearAverage)),
tempRFLRaverageString = ((TextView) findViewById(R.id.tempRFLRaverage)),
tempLFRRaverageString = ((TextView) findViewById(R.id.tempLFRRaverage)),
tempRSaverageString = ((TextView) findViewById(R.id.tempRSaverage)),
tempLSaverageString = ((TextView) findViewById(R.id.tempLSaverage));
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tiretemps);
Button calculate = ((Button) findViewById(R.id.calculate));
calculate.setOnClickListener( new View.OnClickListener() {
public void onClick(View arg0) {
double tempLFouter, tempLFmiddle, tempLFinner, tempRFinner, tempRFmiddle,
tempRFouter, tempLRouter, tempLRmiddle, tempLRinner, tempRRinner,
tempRRmiddle, tempRRouter, tempNoseAverage, tempLFaverage, tempRFaverage,
tempLRaverage, tempRRaverage, tempRearAverage, tempRFLRaverage, tempLFRRaverage,
tempLSaverage, tempRSaverage;
try {
tempLFouter = Double.parseDouble(tempLFouterString.getText().toString());
tempLFinner = Double.parseDouble(tempLFinnerString.getText().toString());
tempLFmiddle = Double.parseDouble(tempLFmiddleString.getText().toString());
tempRFouter = Double.parseDouble(tempRFouterString.getText().toString());
tempRFmiddle = Double.parseDouble(tempRFmiddleString.getText().toString());
tempRFinner = Double.parseDouble(tempRFinnerString.getText().toString());
tempRRouter = Double.parseDouble(tempRRouterString.getText().toString());
tempRRmiddle = Double.parseDouble(tempRRmiddleString.getText().toString());
tempRRinner = Double.parseDouble(tempRRinnerString.getText().toString());
tempLRouter = Double.parseDouble(tempLRouterString.getText().toString());
tempLRmiddle = Double.parseDouble(tempLRmiddleString.getText().toString());
tempLRinner = Double.parseDouble(tempLRinnerString.getText().toString());
tempLFaverage = ((tempLFinner + tempLFmiddle + tempLFouter) / 3);
tempRFaverage = ((tempRFinner + tempRFmiddle + tempRFouter) / 3);
tempLRaverage = ((tempLRinner + tempLRmiddle + tempLRouter) / 3);
tempRRaverage = ((tempRRinner + tempRRmiddle + tempRRouter) / 3);
tempNoseAverage = ((tempLFaverage + tempRFaverage) / 2);
tempRearAverage = ((tempLRaverage + tempRRaverage) / 2);
tempRFLRaverage = ((tempRFaverage + tempLRaverage) / 2);
tempLFRRaverage = ((tempLFaverage + tempRRaverage) / 2);
tempLSaverage = ((tempLFaverage + tempLRaverage) / 2);
tempRSaverage = ((tempRFaverage + tempRRaverage) / 2);
tempNoseAverageString.setText(String.valueOf(String.format("%.1f", tempNoseAverage)) + "°");
tempLFaverageString.setText(String.valueOf(String.format("%.1f", tempLFaverage)) + "°");
tempRFaverageString.setText(String.valueOf(String.format("%.1f", tempRFaverage)) + "°");
tempLRaverageString.setText(String.valueOf(String.format("%.1f", tempLRaverage)) + "°");
tempRRaverageString.setText(String.valueOf(String.format("%.1f", tempRRaverage)) + "°");
tempRearAverageString.setText(String.valueOf(String.format("%.1f", tempRearAverage)) + "°");
tempRFLRaverageString.setText(String.valueOf(String.format("%.1f", tempRFLRaverage)) + "°");
tempLFRRaverageString.setText(String.valueOf(String.format("%.1f", tempLFRRaverage)) + "°");
tempLSaverageString.setText(String.valueOf(String.format("%.1f", tempLSaverage)) + "°");
tempRSaverageString.setText(String.valueOf(String.format("%.1f", tempRSaverage)) + "°");
} catch (NumberFormatException e) {
Toast andEggs = Toast
.makeText(TireTemps.this,
"Please verify only numbers are used in your inputs with no blank data.",
Toast.LENGTH_LONG);
andEggs.show();
} catch (NullPointerException n) {
Toast andEggs = Toast.makeText(TireTemps.this, "Please enter all temperature data for each tire.",
Toast.LENGTH_LONG);
andEggs.show();
}
}
});
Button reset_temps = ((Button) findViewById(R.id.reset_temps));
reset_temps.setOnClickListener( new View.OnClickListener() {
public void onClick(View arg0) {
tempLFouterString.setText("");
tempLFinnerString.setText("");
tempLFmiddleString.setText("");
tempRFouterString.setText("");
tempRFmiddleString.setText("");
tempRFinnerString.setText("");
tempRRouterString.setText("");
tempRRmiddleString.setText("");
tempRRinnerString.setText("");
tempLRouterString.setText("");
tempLRmiddleString.setText("");
tempLRinnerString.setText("");
tempNoseAverageString.setText("");
tempLFaverageString.setText("");
tempRFaverageString.setText("");
tempLRaverageString.setText("");
tempRRaverageString.setText("");
tempRearAverageString.setText("");
tempRFLRaverageString.setText("");
tempLFRRaverageString.setText("");
tempLSaverageString.setText("");
tempRSaverageString.setText("");
Toast andEggs = Toast.makeText(TireTemps.this, "All data has been reset.", Toast.LENGTH_LONG);
andEggs.show();
}
});
}
public void onClick(View arg0) {
// TODO Auto-generated method stub
}
}
编辑：添加了TireTemps.java
答案 0 :(得分：1)
findviewbyid仅在完成setContentView后才起作用。但是您在类实例化本身实例化所有EditTexts。 findviewbyid无法知道在哪里查找ID。
将您在字段实例化中完成的所有findviewbyid移动到Oncreate。
答案 1 :(得分：0)
Tiretemps.java第25行正在访问尚未实例化的变量，或者在访问它时为null。
这可以基于您如何声明变量，根本不将它们设置为值，或者基于它们被清除的其他生命周期函数，例如onPause或onResume < / p>