当我单击按钮时，我的PopUpWindow没有打开

Question

Basically, the button I click is for a store, and I'd like it to cause a PopUpWindow to appear from which you can buy upgrades (much like the Cookie Clicker menu). However, when I click the button, the app crashes. Someone's similar post said that the error produced was as a result of the contentView not being set, so I set this, but it only works if I set the contentView to the very layout that I'm using as a popup, which means I have a popup, but not over the original, main layout.

My Java code:

package com.bipbapapps.leagueclickerapp;


import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Typeface;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.PopupWindow;
import android.widget.TextView;

public class MainClass extends Activity implements OnClickListener {


public float goldCount;
Button minionClick;
Button storeClick;
TextView textGoldCount;
String textTotal;
private SharedPreferences prefs;

@Override
public void onCreate (Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //Set full-screen
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.mainlayout);

    prefs = getSharedPreferences("LeagueClicker", Context.MODE_PRIVATE);


    goldCount = prefs.getFloat("goldCount", 0.0f);

    //Linking the variables
    minionClick = (Button) findViewById(R.id.minioncentreid);
    storeClick = (Button) findViewById(R.id.storeimageid);
    textGoldCount = (TextView) findViewById(R.id.textviewtop);

    //String which will display at the top of the app
    textTotal = goldCount + " Gold";

    //Setting TextView to the String
    textGoldCount.setText(textTotal);
    textGoldCount.setGravity(Gravity.CENTER);
    Typeface tf = Typeface.createFromAsset(getAssets(), "mechanical.ttf");
    textGoldCount.setTypeface(tf);
    textGoldCount.setTextSize(35);

    //Setting onClickListener
    minionClick.setOnClickListener(this);
    storeClick.setOnClickListener(this);

}


@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    switch (v.getId()){
    case R.id.minioncentreid:
    goldCount += 1.0;
    prefs.edit().putFloat("goldCount", goldCount).commit();
    textTotal = goldCount + " Gold";
    textGoldCount.setText(textTotal);
    textGoldCount.setGravity(Gravity.CENTER);
    break;

    case R.id.storeimageid:
        LayoutInflater inflater = (LayoutInflater)
           this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        PopupWindow pw = new PopupWindow(
           inflater.inflate(R.layout.storemenu, null, false), 
           100, 
           100, 
           true);
        pw.showAtLocation(this.findViewById(R.id.storemenuid), Gravity.CENTER, 0, 0);

    }


}


@Override
public void onPause(){
    super.onPause();
    prefs.edit().putFloat("goldCount", goldCount).commit();
}

@Override
public void onResume(){
    super.onResume();
    goldCount = prefs.getFloat("goldCount", 0.0f);
}

@Override
public void onStop(){
    super.onStop();
    prefs.edit().putFloat("goldCount", goldCount).commit();
    Log.d(prefs.getFloat("goldCount", 0.0f)+"derprolw", "ejwfjbrea");
}




}

LogCat errors:

04-22 06:24:52.408: D/gralloc_goldfish(2931): Emulator without GPU emulation detected.
04-22 06:24:57.808: D/dalvikvm(2931): GC_FOR_ALLOC freed 2121K, 10% free 20151K/22340K, paused 111ms, total 114ms
04-22 06:24:58.368: D/AndroidRuntime(2931): Shutting down VM
04-22 06:24:58.368: W/dalvikvm(2931): threadid=1: thread exiting with uncaught exception (group=0xb2a1cba8)
04-22 06:24:58.418: E/AndroidRuntime(2931): FATAL EXCEPTION: main
04-22 06:24:58.418: E/AndroidRuntime(2931): Process: com.bipbapapps.leagueclickerapp, PID: 2931
04-22 06:24:58.418: E/AndroidRuntime(2931): java.lang.NullPointerException
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.widget.PopupWindow.showAtLocation(PopupWindow.java:814)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at com.bipbapapps.leagueclickerapp.MainClass.onClick(MainClass.java:86)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.view.View.performClick(View.java:4438)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.view.View$PerformClick.run(View.java:18422)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.os.Handler.handleCallback(Handler.java:733)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.os.Handler.dispatchMessage(Handler.java:95)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.os.Looper.loop(Looper.java:136)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at android.app.ActivityThread.main(ActivityThread.java:5017)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at java.lang.reflect.Method.invokeNative(Native Method)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at java.lang.reflect.Method.invoke(Method.java:515)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-22 06:24:58.418: E/AndroidRuntime(2931):     at dalvik.system.NativeStart.main(Native Method)
04-22 06:25:01.358: I/Process(2931): Sending signal. PID: 2931 SIG: 9

Does anyone know how I may fix this issue?

Answer 1

Looks to me like you have a null pointer at this line (line 86?) :

pw.showAtLocation(this.findViewById(R.id.storemenuid), Gravity.CENTER, 0, 0);

Try replacing this.findViewById(R.id.storemenuid) with v, as technically they are the same except we know that v is not null or else this line would not be reached. Also the other values are constant so we know they are not null either.

let me know if this helps, or if it provides you with any more information.

---

edit

Also other cause could be in the constructor:

 PopupWindow pw = new PopupWindow(
       inflater.inflate(R.layout.storemenu, null, false), 
       100, 
       100, 
       true);

But I find this less likely as it should have notified you of the null pointer referring to that line.

Answer 2

尝试执行以下操作：

PopupWindow.setWindowLayoutMode(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);