Java 安卓开发:“;带未捕获异常的线程退出”;
我正在尝试创建我的第一个Android应用程序(一个游戏),但我在开始时遇到了一些困难 当我运行代码时,会得到以下错误日志:Java 安卓开发:“;带未捕获异常的线程退出”;,java,android,Java,Android,我正在尝试创建我的第一个Android应用程序(一个游戏),但我在开始时遇到了一些困难 当我运行代码时,会得到以下错误日志: 05-25 02:41:51.022: WARN/dalvikvm(634): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 05-25 02:41:51.040: ERROR/AndroidRuntime(634): FATAL EXCEPTION: main 05-25 02
05-25 02:41:51.022: WARN/dalvikvm(634): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): FATAL EXCEPTION: main
05-25 02:41:51.040: ERROR/AndroidRuntime(634): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.stickfigs.nmg/com.stickfigs.nmg.NMG}: java.lang.NullPointerException
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.os.Handler.dispatchMessage(Handler.java:99)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.os.Looper.loop(Looper.java:123)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread.main(ActivityThread.java:4627)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at java.lang.reflect.Method.invokeNative(Native Method)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at java.lang.reflect.Method.invoke(Method.java:521)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at dalvik.system.NativeStart.main(Native Method)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): Caused by: java.lang.NullPointerException
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at com.stickfigs.nmg.NMG.onCreate(NMG.java:32)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): ... 11 more
05-25 02:41:51.062: WARN/ActivityManager(59): Force finishing activity com.stickfigs.nmg/.NMG
我认为问题在于“线程以未捕获的异常退出”部分,我不知道异常可能是什么,也不知道是什么导致了它
这是我的密码:
NMGView.java:
包com.stickfigs.NMG
import android.content.Context;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
class NMGView extends SurfaceView implements SurfaceHolder.Callback {
class NMGThread extends Thread {
//State-tracking constants
public static final int STATE_LOSE = 1;
public static final int STATE_PAUSE = 2;
public static final int STATE_READY = 3;
public static final int STATE_RUNNING = 4;
public static final int STATE_WIN = 5;
/** The state of the game. One of READY, RUNNING, PAUSE, LOSE, or WIN */
private int mode;
/** Handle to the surface manager object we interact with */
private SurfaceHolder surfaceHolder;
public NMGThread(SurfaceHolder surfaceHolderc, Context contextc) {
// get handles to some important objects
surfaceHolder = surfaceHolderc;
context = contextc;
}
/**
* Restores game state from the indicated Bundle. Typically called when
* the Activity is being restored after having been previously
* destroyed.
*
* @param savedState Bundle containing the game state
*/
public synchronized void restoreState(Bundle savedState) {
synchronized (surfaceHolder) {
setState(STATE_PAUSE);
}
}
/**
* Sets the game mode. That is, whether we are running, paused, in the
* failure state, in the victory state, etc.
*
* @param mode one of the STATE_* constants
* @param message string to add to screen or null
*/
public void setState(int modec) {
synchronized (surfaceHolder) {
mode = modec;
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
/** Handle to the application context, used to e.g. fetch Drawables. */
private Context context;
/** The thread that actually draws the animation */
private NMGThread thread;
public NMGView(Context context, AttributeSet attrs) {
super(context, attrs);
// register our interest in hearing about changes to our surface
SurfaceHolder holder = getHolder();
holder.addCallback(this);
// create thread only; it's started in surfaceCreated()
thread = new NMGThread(holder, context);
setFocusable(true); // make sure we get key events
}
/**
* Fetches the animation thread corresponding to this LunarView.
*
* @return the animation thread
*/
public NMGThread getThread() {
return thread;
}
}
NMG.java:
package com.stickfigs.nmg;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import com.stickfigs.nmg.NMGView.NMGThread;
public class NMG extends Activity {
/** Called when the activity is first created. */
/** A handle to the thread that's actually running the animation. */
private NMGThread nMGThread;
/** A handle to the View in which the game is running. */
private NMGView nMGView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Turn off the window's title bar
// TODO Turn off the status bar
requestWindowFeature(Window.FEATURE_NO_TITLE);
// tell system to use the layout defined in our XML file
setContentView(R.layout.nmg_layout);
// get handles to the LunarView from XML, and its LunarThread
nMGView = (NMGView) findViewById(R.id.nmg);
nMGThread = nMGView.getThread();
if (savedInstanceState == null) {
// we were just launched: set up a new game
nMGThread.setState(NMGThread.STATE_READY);
Log.w(this.getClass().getName(), "SIS is null");
} else {
// we are being restored: resume a previous game
nMGThread.restoreState(savedInstanceState);
Log.w(this.getClass().getName(), "SIS is nonnull");
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.stickfigs.nmg.NMGView
android:id="@+id/nmg"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</FrameLayout>
更新:这是我的R.java和nmg_layout.xml:
R.java:
包com.stickfigs.nmg
public final class R {
public static final class attr {
}
public static final class drawable {
public static final int icon=0x7f020000;
}
public static final class id {
public static final int nmg=0x7f050000;
}
public static final class layout {
public static final int nmg_layout=0x7f030000;
}
public static final class string {
public static final int app_name=0x7f040001;
public static final int hello=0x7f040000;
}
}
nmg\u layout.xml:
package com.stickfigs.nmg;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import com.stickfigs.nmg.NMGView.NMGThread;
public class NMG extends Activity {
/** Called when the activity is first created. */
/** A handle to the thread that's actually running the animation. */
private NMGThread nMGThread;
/** A handle to the View in which the game is running. */
private NMGView nMGView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Turn off the window's title bar
// TODO Turn off the status bar
requestWindowFeature(Window.FEATURE_NO_TITLE);
// tell system to use the layout defined in our XML file
setContentView(R.layout.nmg_layout);
// get handles to the LunarView from XML, and its LunarThread
nMGView = (NMGView) findViewById(R.id.nmg);
nMGThread = nMGView.getThread();
if (savedInstanceState == null) {
// we were just launched: set up a new game
nMGThread.setState(NMGThread.STATE_READY);
Log.w(this.getClass().getName(), "SIS is null");
} else {
// we are being restored: resume a previous game
nMGThread.restoreState(savedInstanceState);
Log.w(this.getClass().getName(), "SIS is nonnull");
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.stickfigs.nmg.NMGView
android:id="@+id/nmg"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</FrameLayout>
如果查看堆栈跟踪,您将看到一行“由…引起的”(有时不止一行)。最后一个是重要的。它说NMG.java的第32行有一个空指针异常。该行及其前面的行是:
nMGView = (NMGView) findViewById(R.id.nmg);
nMGThread = nMGView.getThread();
显然,布局
R.layout.nmg\u布局中没有id为R.id.nmg
的视图。这就是造成问题的原因。在XML文件中,R.id.nmg
确实存在。
因此,我认为问题是由从资源中膨胀NMGView
对象引起的。
您应该检查NMGView
源代码,尤其是其构造函数中的源代码。发生此问题的原因是,销毁SurfaceView时,SurfaceView onDraw()方法大部分时间都在运行,然后会出现空指针错误,因为此时画布不存在。我已修复了使用NullPointerException捕获所有绘图内容的问题:
@Override
public void onDraw(Canvas canvas) {
try {
//Drawing Stuff
}catch(NullPointerException e){
Log.e("NULL POINTER EXCEPTION","Canvas NULL POINTER");
}
}
如果在主活动中实现onPause()、onDestroy()方法,您将获得以下顺序:第一:E/onPause﹕ 暂停时-->下一个E/surfaced行程﹕ 表面损坏-->E/NULL指针异常﹕ 画布空指针-->最终
E/onDestroy﹕ 论毁灭
这是我正在使用的surfaceDestroyed方法:
@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
Log.e("surfaceDestroyed", "SURFACE DESTROYED ");
thread.setRunning(false);
try {
//thread.setRunning(false);
thread.join();
} catch (InterruptedException e) {
Log.e("Surface Thread Stopped","SURFACE THREAD STOPPED");
}
}
如果在“build.gradle(Module:app)”中使用“multiDexEnabled true”,请从“defaultConfig”中删除此行并同步项目。
它在我的情况下工作 这很奇怪,因为它确实存在于布局文件和R中。我将这两者都添加到了我的原始问题中。也许我数错了?如果没有,我建议添加行assert nMGView!=无效代码>位于这两行之间。看看这是否会导致你的应用程序崩溃,原因是断言失败而不是NPE。尝试了之后,它仍然失败,原因与之前相同。第32行仍然是NPE?你能确认我数的行数正确吗?或者指向生成异常的行。很高兴它能工作。为便于将来参考,请通过选择project>clean。。。从Eclipse菜单中。我不确定通货膨胀是什么意思。你能解释一下你的意思吗?我认为这是不对的。如果问题是由于在扩展nmg_布局时实例化NMGView引起的,则调用setContentView
将生成异常。稍后会出现异常。嘿,你能告诉我你是如何正确地解决这个错误的,因为我得到了同样的错误,当我评论logcat中提到的行时,它指出了不同的行。有点奇怪???