java无法在Android中启动新活动

Question

我正在写一个游戏，游戏结束后我需要切换活动。我的问题是我有一个扩展到Activity的gameLogic Java类，它不是一个主Activity类

所以我在GameLogic类中有一个gameover方法，它返回布尔值。如果返回false，则必须切换到第二个活动，但没有。它返回null.pointer.exception

代码如下：

public void gameOver(GameData data){

        if(!intersect(data)){

            Intent intent = new Intent(GameLogic.this , SecondActivity.class);
            startActivity(intent);

        }
}

我在OnDraw方法的GameData类中调用这个方法，因为OnDraw方法总是要控制它是否是gameover

protected void onDraw(Canvas canvas){
.........
....
......
.....
............
logic.gameOver(this);

}

错误：

08-20 14:13:58.293 29830-29830/com.example.msimsi.myapplication E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.example.msimsi.myapplication, PID: 29830
java.lang.NullPointerException: Attempt to invoke virtual method

'java.lang.String 安卓.content.Context.getPackageName()' on a null object reference at 安卓.content.ContextWrapper.getPackageName(ContextWrapper.java:132) at 安卓.content.ComponentName.(ComponentName.java:77) at 安卓.content.Intent.(Intent.java:4160) at com.example.msimsi.myapplication.GameLogic.gameOver(GameLogic.java:230) at com.example.msimsi.myapplication.GameData.onDraw(GameData.java:86) at 安卓.view.View.draw(View.java:15231) at 安卓.view.View.updateDisplayListIfDirty(View.java:14167) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3389) at 安卓.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3368) at 安卓.view.View.updateDisplayListIfDirty(View.java:14127) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3389) at 安卓.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3368) at 安卓.view.View.updateDisplayListIfDirty(View.java:14127) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3389) at 安卓.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3368) at 安卓.view.View.updateDisplayListIfDirty(View.java:14127) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3389) at 安卓.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3368) at 安卓.view.View.updateDisplayListIfDirty(View.java:14127) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3389) at 安卓.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3368) at 安卓.view.View.updateDisplayListIfDirty(View.java:14127) at 安卓.view.View.getDisplayList(View.java:14189) at 安卓.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:273) at 安卓.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:279) at 安卓.view.ThreadedRenderer.draw(ThreadedRenderer.java:318) at 安卓.view.ViewRootImpl.draw(ViewRootImpl.java:2530) at 安卓.view.ViewRootImpl.performDraw(ViewRootImpl.java:2352) at 安卓.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1982) at 安卓.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061) at 安卓.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885) at 安卓.view.Choreographer$CallbackRecord.run(Choreographer.java:767) at 安卓.view.Choreographer.doCallbacks(Choreographer.java:580) at 安卓.view.Choreographer.doFrame(Choreographer.java:550) at 安卓.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) at 安卓.os.Handler.handleCallback(Handler.java:739) at 安卓.os.Handler.dispatchMessage(Handler.java:95) at 安卓.os.Looper.loop(Looper.java:135) at 安卓.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

您需要获取应用程序上下文

Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
startActivity(intent);

我不是专家