Question

我有一个方法可以点击创建弹出窗口，名为onBalloonTap，我正在尝试在另一个班级CallPopup()中调用pip。我究竟做错了什么？我不应该通过方法调用意图吗？我的目标是在调用onBalloonTap时启动另一个活动。有更好的方法吗？

CallPopUp()

中的

pip

public void CallPopup()
{   Log.i("CallPopup", "Started CallPopup");
    startActivity(intent);
    finish();
}

从另一个班级的onBalloonTap调用

protected boolean onBalloonTap(int index, OverlayItem item) {
    Toast.makeText(c, "onBalloonTap for overlay index " + index,
            Toast.LENGTH_LONG).show();
    pip pipinst =new pip();
    pipinst.CallPopup();
    return true;
}

我得到这个日志：

05-04 22:33:41.022: ERROR/AndroidRuntime(704): FATAL EXCEPTION: main
05-04 22:33:41.022: ERROR/AndroidRuntime(704): java.lang.NullPointerException
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.app.Activity.startActivityForResult(Activity.java:2817)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.app.Activity.startActivity(Activity.java:2923)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.appname.pip.pip.CallPopup(pip.java:192)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.appname.pip.MyItemizedOverlay.onBalloonTap(MyItemizedOverlay.java:67)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.readystatesoftware.mapviewballoons.BalloonItemizedOverlay$1.onTouch(BalloonItemizedOverlay.java:203)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.View.dispatchTouchEvent(View.java:3762)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:897)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1671)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1655)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1785)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.os.Looper.loop(Looper.java:123)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at java.lang.reflect.Method.invokeNative(Native Method)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at java.lang.reflect.Method.invoke(Method.java:521)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-04 22:33:41.022: ERROR/AndroidRuntime(704):     at dalvik.system.NativeStart.main(Native Method)
05-04 22:33:41.102: WARN/ActivityManager(38):   Force finishing activity com.appname.pip/.pip
05-04 22:33:41.952: WARN/ActivityManager(38): Activity pause timeout for HistoryRecord{43f680f0 com.appname.pip/.pip}

Answer 1

您需要在intent中声明您使用的CallPopup() 这可能是您获得NullPointerException的原因。

Answer 2

看起来“pip”类扩展了Activity，但你只是在不经过任何Activity生命周期的情况下创建一个pip对象。空指针异常可能是因为你的pip对象不知道它的父Context是什么。您几乎肯定可以访问onBalloonTap中的Context对象（例如，View.getContext()），那么为什么不从那里调用Context.startActivity()呢？

Android从另一个类中的方法调用Intent

2 个答案: