Question

基本上我想从按下的按钮开始一个新的活动。其他一切都很好。它说

不幸的是应用程序停止了

按下按钮时。第二项活动在androidManifest。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.bisesifreelance.maxbisesi.tic_tac_toe">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".GamePlayActivity">


    </activity>
</application>

</manifest>

logcat的：

FATAL EXCEPTION: main
    Process: com.bisesifreelance.maxbisesi.tic_tac_toe, PID: 3339
    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.bisesifreelance.maxbisesi.tic_tac_toe/com.bisesifreelance.maxbisesi.tic_tac_toe.GamePlayActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2327)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
        at android.app.ActivityThread.-wrap11(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
        at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:116)
        at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:147)
        at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:27)
        at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:50)
        at android.support.v7.app.AppCompatDelegateImplV23.<init>(AppCompatDelegateImplV23.java:29)
        at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:199)
        at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:181)
        at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:521)
        at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:190)
        at com.bisesifreelance.maxbisesi.tic_tac_toe.GamePlayActivity.<init>(GamePlayActivity.java:12)
        at java.lang.Class.newInstance(Native Method)
        at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2317)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

09-07 09:24:41.132 3339-3339/? I/Process: Sending signal. PID: 3339 SIG: 9

Answer 1

你的java代码在哪里？

可能您无法按引用ID初始化按钮。

是oncreate（）方法中的初始化按钮。

private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
button= (Button)findViewById(R.id.btnSend); // Are u missing here ??
}

在尝试从按钮启动新活动后，Unfortunatley应用已在模拟器中停止

1 个答案: