Java 如何从弹出窗口开始活动?
我有一个自定义的弹出窗口,在我的活动中有自己的布局(负责弹出窗口工作的代码在单独的类PopupUpIndowActivity中)。我想在此弹出窗口打开活动中指定一个按钮。我尝试了一些方法,但应用程序因NullPointerException崩溃 此活动的代码如下所示:Java 如何从弹出窗口开始活动?,java,android,android-activity,Java,Android,Android Activity,我有一个自定义的弹出窗口,在我的活动中有自己的布局(负责弹出窗口工作的代码在单独的类PopupUpIndowActivity中)。我想在此弹出窗口打开活动中指定一个按钮。我尝试了一些方法,但应用程序因NullPointerException崩溃 此活动的代码如下所示: public class FirstActivity extends Activity implements OnClickListener { @Override public void onCreate(Bundle sav
public class FirstActivity extends Activity implements OnClickListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView popupButton = (ImageView) this.findViewById(R.id.popup_btn);
likemenuButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
PopupWindow dw = new PopupWindow(v);
dw.showLikePopDownMenu();
}
});
}
// my stuff
//popup window
private class PopupWindow extends PopupWindowActivity implements OnClickListener {
public PopupWindow(View anchor) {
super(anchor);
}
@Override
protected void onCreate() {
// inflate layout
LayoutInflater inflater =
(LayoutInflater) this.anchor.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.popup, null);
// setup button events
ImageView aboutButton = (ImageView) findViewById(R.id.btn_about);
aboutButton.setOnClickListener(this);
this.setContentView(root);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_about: {
Intent activity = new Intent(FistActivity.this, About.class);
startActivity(activity);
break;
}
}
}}
}
另一方面:
private static class PopupWindow extends PopupWindowActivity implements OnClickListener {
public PopupWindow(View anchor) {
super(anchor);
}
@Override
protected void onCreate() {
// inflate layout
LayoutInflater inflater =
(LayoutInflater) this.anchor.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.popup, null);
// setup button events
ImageView searchButton = (ImageView) findViewById(R.id.btn_about);
algebraButton.setOnClickListener(this);
this.setContentView(root);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_about: {
Intent intent = new Intent();
intent.setClass(this, About.class);
startActivity(intent);
break;
}
default:
break;
}
}}
eclipse说,首先我应该从私有静态类PopupWindow扩展PopupWindowActivity实现中删除静态
,然后我对intent.setClass(这是关于.class)有以下内容:代码>:
类型Intent中的方法setClass(Context,Class)不适用于参数
(FirstActivity.PopupWindow,类)
请帮忙
添加了第一次崩溃的日志:
03-07 00:28:07.750: D/AndroidRuntime(12472): Shutting down VM
03-07 00:28:07.750: W/dalvikvm(12472): threadid=1: thread exiting with uncaught exception (group=0x40018578)
03-07 00:28:07.759: E/AndroidRuntime(12472): FATAL EXCEPTION: main
03-07 00:28:07.759: E/AndroidRuntime(12472): java.lang.NullPointerException
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.example.FirstActivity$PopupWindow.onCreate(FirstActivity.java:110)
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.quickaction.PopupWindowActivity.<init>(PopupWindowActivity.java:52)
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.example.FirstActivity$PopupWindow.<init>(FirstActivity.java:97)
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.example.FirstActivity$1.onClick(FirstActivity.java:30)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.view.View.performClick(View.java:2485)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.view.View$PerformClick.run(View.java:9080)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.os.Handler.handleCallback(Handler.java:587)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.os.Handler.dispatchMessage(Handler.java:92)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.os.Looper.loop(Looper.java:130)
03-07 00:28:07.759: E/AndroidRuntime(12472): at android.app.ActivityThread.main(ActivityThread.java:3687)
03-07 00:28:07.759: E/AndroidRuntime(12472): at java.lang.reflect.Method.invokeNative(Native Method)
03-07 00:28:07.759: E/AndroidRuntime(12472): at java.lang.reflect.Method.invoke(Method.java:507)
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
03-07 00:28:07.759: E/AndroidRuntime(12472): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
03-07 00:28:07.759: E/AndroidRuntime(12472): at dalvik.system.NativeStart.main(Native Method)
03-07 00:28:07.750:D/AndroidRuntime(12472):关闭虚拟机
03-07 00:28:07.750:W/dalvikvm(12472):threadid=1:线程以未捕获异常退出(组=0x40018578)
03-07 00:28:07.759:E/AndroidRuntime(12472):致命异常:主
03-07 00:28:07.759:E/AndroidRuntime(12472):java.lang.NullPointerException
03-07 00:28:07.759:E/AndroidRuntime(12472):在com.example.FirstActivity$PopupWindow.onCreate(FirstActivity.java:110)
03-07 00:28:07.759:E/AndroidRuntime(12472):在com.quickaction.poppUpindowActivity上。(poppUpindowActivity.java:52)
03-07 00:28:07.759:E/AndroidRuntime(12472):在com.example.FirstActivity$PopupWindow。(FirstActivity.java:97)
03-07 00:28:07.759:E/AndroidRuntime(12472):位于com.example.FirstActivity$1.onClick(FirstActivity.java:30)
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.view.view.performClick(view.java:2485)上
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.view.view$PerformClick.run(view.java:9080)
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.os.Handler.handleCallback(Handler.java:587)上
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.os.Handler.dispatchMessage(Handler.java:92)上
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.os.Looper.loop(Looper.java:130)上
03-07 00:28:07.759:E/AndroidRuntime(12472):在android.app.ActivityThread.main(ActivityThread.java:3687)上
03-07 00:28:07.759:E/AndroidRuntime(12472):位于java.lang.reflect.Method.Invokenactive(本机方法)
03-07 00:28:07.759:E/AndroidRuntime(12472):位于java.lang.reflect.Method.invoke(Method.java:507)
03-07 00:28:07.759:E/AndroidRuntime(12472):在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
03-07 00:28:07.759:E/AndroidRuntime(12472):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
03-07 00:28:07.759:E/AndroidRuntime(12472):在dalvik.system.NativeStart.main(本机方法)
按下按钮:
Intent intent = new Intent("<your-intent-goes-here");
<context>.startActivity(intent);
Intent Intent=new Intent(“按按钮时:
Intent intent = new Intent("<your-intent-goes-here");
<context>.startActivity(intent);
Intent Intent=新的Intent(“有很多方法可以解决这个问题。一种是通过对话框的构造函数传递对上下文的引用。有很多方法可以解决这个问题。一种是通过对话框的构造函数传递对上下文的引用。如果它因NullPointerException崩溃,你能在你的问题中包含堆栈跟踪吗关于?@jbowes我在问题中添加了日志。如果它因NullPointerException崩溃,您可以在问题中包括堆栈跟踪吗?@jbowes我在问题中添加了日志。我应该放什么来代替“@Sabre您在清单中的活动的意图过滤器中定义的意图。在类的位置放置一个可以访问startActivity@Sabre在你的情况下,它将是poppuphindow。这个。startActivity(intent)我不太懂英语,我仍然不明白我应该用什么来代替“你的意图…”但是当我把PopupWindow而不是eclipse类放在上面时说,类型StartAction的方法startActivity(Intent)是未定义的。PopupWindow
@Sabre你需要一个上下文对象来调用startActivity()。然后调用打开你想要打开的活动的Intent…你看过开发指南了吗()我应该放什么来代替清单中您在活动的意图过滤器中定义的“@Sabre意图。在类的位置放一个可以访问startActivity@Sabre在您的情况下,它将是poppuphindow.this.startActivity(intent)我不太懂英语,我仍然不明白我应该用什么来代替“your intent…”。但是当我用PopupWindow代替类eclipse时,我说类型startActivity(intent)的方法startActivity(intent)没有定义。PopupWindow
@Sabre你需要一个上下文对象来调用startActivity()。然后调用打开您想要打开的活动的意图…您是否查看了开发指南()