Java 我需要取消弹出窗口，但取消功能不是'；行不通

标题描述得相当好；弹出窗口打开，并用作我的游戏菜单。但是，当我尝试使用按钮关闭菜单时，Eclipse说“局部变量pw可能尚未初始化”：\

我的Java代码：

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.PopupWindow.OnDismissListener;
import android.widget.TextView;

public class MainClass extends Activity implements OnClickListener {

public float goldCount;
Button minionClick;
Button storeClick;
Button storeDismiss;
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);
    storeDismiss = (Button) findViewById(R.id.menudismissid);
    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);
    storeDismiss.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), 
           300, 
           450, 
           true);
        pw.showAtLocation(v, Gravity.CENTER, 0, 0);

    case R.id.menudismissid:
        pw.dismiss();
        break;

    }


}


@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");
}

}

有人知道我如何设置按钮来关闭弹出窗口吗

编辑：现在产生的LogCat错误：

04-22 15:20:04.478: E/AndroidRuntime(3491): FATAL EXCEPTION: main
04-22 15:20:04.478: E/AndroidRuntime(3491): Process: com.bipbapapps.leagueclickerapp, PID: 3491
04-22 15:20:04.478: E/AndroidRuntime(3491): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.bipbapapps.leagueclickerapp/com.bipbapapps.leagueclickerapp.MainClass}: java.lang.NullPointerException
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.os.Handler.dispatchMessage(Handler.java:102)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.os.Looper.loop(Looper.java:136)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread.main(ActivityThread.java:5017)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at java.lang.reflect.Method.invokeNative(Native Method)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at java.lang.reflect.Method.invoke(Method.java:515)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at dalvik.system.NativeStart.main(Native Method)
04-22 15:20:04.478: E/AndroidRuntime(3491): Caused by: java.lang.NullPointerException
04-22 15:20:04.478: E/AndroidRuntime(3491):     at com.bipbapapps.leagueclickerapp.MainClass.onCreate(MainClass.java:66)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.Activity.performCreate(Activity.java:5231)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-22 15:20:04.478: E/AndroidRuntime(3491):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)

编辑2：

因此，通过一些帮助和编辑，我们找到了代码：

//Initialize variables from popup window
     LayoutInflater inflater = (LayoutInflater)
           this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    PopupWindow pw = new PopupWindow(
               inflater.inflate(R.layout.storemenu, null, false)); 
    storeDismiss = (Button) pw.getContentView().findViewById(R.id.menudismissid);

---

代替“storedismise=（按钮）findViewById（R.id.menudismissid）；”。现在唯一的问题是该按钮实际上并没有关闭菜单：（

我认为不能在另一个case块中使用在一个case块中定义的变量。因为case块没有特定的执行顺序。更好的方法是将

PopupWindow

声明为类的成员变量

public class MainClass extends Activity implements OnClickListener {

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

@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);
    storeDismiss = (Button) findViewById(R.id.menudismissid);
    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);
    storeDismiss.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);

        if(pw == null) {
        pw = new PopupWindow(
           inflater.inflate(R.layout.storemenu, null, false), 
           300, 
           450, 
           true);
        }
        pw.showAtLocation(v, Gravity.CENTER, 0, 0);
         break;

    case R.id.menudismissid:
        if (pw != null) {
        pw.dismiss();
        }
        break;

    }

另外，不要忘记在第一个case块的末尾添加

break

语句：）

编辑1: 您可以通过以下方式访问

PopUpWindow

的视图元素：

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

//Initialize variables from popup window
 LayoutInflater inflater = (LayoutInflater)
       this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
PopupWindow pw = new PopupWindow(
           inflater.inflate(R.layout.storemenu, null, false), 
storeDismiss = pw.getContentView().findViewById(R.id.menudismissid);

编辑2:

解散

功能的官方文件说

公开无效解雇（）

添加在API级别1中，处理弹出窗口。这种方法是可行的 仅在打开showAsDropDown（android.view.view）后调用 执行。否则，调用此方法将无效

所以案例2的代码应该是

case R.id.storeimageid:
        LayoutInflater inflater = (LayoutInflater)
           this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        if(pw == null) {
        pw = new PopupWindow(
           inflater.inflate(R.layout.storemenu, null, false), 
           300, 
           450, 
           true);
        }
        pw.showAsDropDown(v, 0, 0, Gravity.CENTER);
         break;

---

您是否缺少一个

中断

在

案例R.id.storeimageid

的末尾和

案例R.id.menudismissid

之前？Eclipse抱怨哪一行？它似乎不起作用：\n这会删除错误，但我的应用程序在加载时崩溃。你能发布异常的LogCat跟踪吗？第66行？双击com.bipbapps.leagueclickerapp.MainClass.onCreate（MainClass.java:66）上logcat

中的此语句

。它将在代码中显示导致

NullPointerExceptio

n的行是“storedismission.setOnClickListener（this）；”。我一直在乱搞代码，但我什么都搞不清楚-仍然没有错误，但应用程序只是在加载时崩溃。似乎

storedismise

为空。您确定主布局中有id为menudismissid的按钮吗？您可以发布

mainlayout.xml

文件的代码吗？