package com.example.popupwindow;
import android.os.Bundle;
import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.PopupWindow;
public class MainActivity extends Activity {
private PopupWindow pwindow;
private Button b,b2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b=(Button)findViewById(R.id.openpopup);
按钮 b 工作但 b2 不工作我正在制作一个 android 应用程序，我需要在单击按钮时弹出一个窗口//但它给出错误我也使用了 try 和 catch 块但它仍然给出 null指针异常尝试通过单击按钮来获取弹出窗口，并且在再次弹出窗口中有一个按钮可以关闭弹出窗口但它没有被唤醒。所以请帮助我。
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
initiatePopUpWindow();
}
});
}
//if i remove thr try and catch block then it is not working..see it for b2
//problem is comming in b2 as click event is not been generated fro that
public void initiatePopUpWindow(){
try{
LayoutInflater linflater=(LayoutInflater)getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
View popupview=linflater.inflate(R.layout.popup,null);
pwindow=new PopupWindow(popupview,LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
pwindow.showAsDropDown(b, 200,50);
b2=(Button)findViewById(R.id.dismiss);
b2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
pwindow.dismiss();
}
});
}catch(Exception e){
e.printStackTrace();
}
}
以下是我的错误日志
09-11 05:28:24.249: W/System.err(449): java.lang.NullPointerException
09-11 05:28:24.269: W/System.err(449): at com.example.popupwindow.MainActivity.initiatePopUpWindow(MainActivity.java:43)
09-11 05:28:24.269: W/System.err(449): at com.example.popupwindow.MainActivity$1.onClick(MainActivity.java:29)
09-11 05:28:24.269: W/System.err(449): at android.view.View.performClick(View.java:4240)
09-11 05:28:24.288: W/System.err(449): at android.view.View$PerformClick.run(View.java:17721)
09-11 05:28:24.288: W/System.err(449): at android.os.Handler.handleCallback(Handler.java:730)
09-11 05:28:24.288: W/System.err(449): at android.os.Handler.dispatchMessage(Handler.java:92)
09-11 05:28:24.300: W/System.err(449): at android.os.Looper.loop(Looper.java:137)
09-11 05:28:24.300: W/System.err(449): at android.app.ActivityThread.main(ActivityThread.java:5103)
09-11 05:28:24.300: W/System.err(449): at java.lang.reflect.Method.invokeNative(Native Method)
09-11 05:28:24.300: W/System.err(449): at java.lang.reflect.Method.invoke(Method.java:525)
09-11 05:28:24.309: W/System.err(449): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-11 05:28:24.309: W/System.err(449): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
my main file-
public class MainActivity extends Activity {
private PopupWindow pwindow;
private Button b,b2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b=(Button)findViewById(R.id.openpopup);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
initiatePopUpWindow();
}
});
}
public void initiatePopUpWindow(){
try{
LayoutInflater linflater=(LayoutInflater)getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
View popupview=linflater.inflate(R.layout.popup,null);
pwindow=new PopupWindow(popupview,LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
pwindow.showAsDropDown(b, 200,50);
b2=(Button)popupview.findViewById(R.id.dismiss);
b2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
pwindow.dismiss();
}
});
}catch(Exception e){
e.printStackTrace();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
my popup.xml file-
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="@android:color/background_light">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="1dp"
android:background="@android:color/darker_gray">
>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="20dp">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="It's a PopupWindow" />
<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher" />
<Button
android:id="@+id/dismiss"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Dismiss" />
</LinearLayout>
</LinearLayout>
</LinearLayout
>