Java 计算器崩溃，数组整数还是整数？

我试图建立一个简单的计算器，但它崩溃了。 我试着调试，发现问题出在数组上

这是我的代码：

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;


public class MainActivity extends Activity {

    private EditText                Scr;
    private float                   NumberBf;
    private String                  Operation;
    private ButtonClickListener     btnClick;

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

        Scr             =       (EditText) findViewById(R.id.resultsBox);
        int idList[]    =       {R.id.b0,R.id.b1,R.id.b2,R.id.b3,R.id.b4,R.id.b5,
                                 R.id.b6,R.id.b7,R.id.b8,R.id.b9,R.id.bpoint,
                                 R.id.clean,R.id.equals,R.id.half,R.id.minus,
                                 R.id.multiply,R.id.plus};

        for(int id:idList)
        {
            View v  =   (View) findViewById(id);
            v.setOnClickListener(btnClick);
        }
        Log.i("for", "for ok");
        setContentView(R.layout.activity_main);
    }

    public void getKeyboard(String str){
        String ScrCurrect   =   Scr.getText().toString();
        ScrCurrect  += str;
        Scr.setText(ScrCurrect);
    }
    public void mResult(){
        float NumAf =   Float.parseFloat(Scr.getText().toString());
        float result = 0;
        if(Operation.equals("+"))
        {
            result  =   NumAf + NumberBf;
        }
        if(Operation.equals("-"))
        {
            result  =   NumAf - NumberBf;
        }
        if(Operation.equals("*"))
        {
            result  =   NumAf * NumberBf;
        }
        if(Operation.equals("/"))
        {
            result  =   NumAf / NumberBf;
        }
        Scr.setText(String.valueOf(result));
    }
    public void mMath(String str){
        NumberBf    =   Float.parseFloat(Scr.getText().toString());
        Operation   =   str;
        Scr.setText("0");
    }
    private class ButtonClickListener implements OnClickListener
    {

        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.clean:
                    Scr.setText("0");
                    NumberBf    =   0;
                    Operation   =   "";
                break;
                case R.id.plus:
                    mMath("+");
                break;
                case R.id.minus:
                    mMath("-");
                break;
                case R.id.multiply:
                    mMath("*");
                break;
                case R.id.half:
                    mMath("/");
                break;
                case R.id.equals:
                    mResult();
                break;

                default:
                    String numb = ((Button)v).getText().toString();
                    getKeyboard(numb);
                break;
            }

        }

    }
}

我的日志是：

> 12-07 21:46:18.242: I/log(20993): id list ok 12-07 21:46:18.242:
> D/AndroidRuntime(20993): Shutting down VM 12-07 21:46:18.242:
> W/dalvikvm(20993): threadid=1: thread exiting with uncaught exception
> (group=0x417cac08) 12-07 21:46:18.242: E/AndroidRuntime(20993): FATAL
> EXCEPTION: main 12-07 21:46:18.242: E/AndroidRuntime(20993): Process:
> com.test.calculator, PID: 20993 12-07 21:46:18.242:
> E/AndroidRuntime(20993): java.lang.RuntimeException: Unable to start
> activity
> ComponentInfo{com.test.calculator/com.test.calculator.MainActivity}:
> java.lang.NullPointerException 12-07 21:46:18.242:
> E/AndroidRuntime(20993):  at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2187)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> android.app.ActivityThread.access$800(ActivityThread.java:138) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> android.os.Handler.dispatchMessage(Handler.java:102) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> android.os.Looper.loop(Looper.java:136) 12-07 21:46:18.242:
> E/AndroidRuntime(20993):  at
> android.app.ActivityThread.main(ActivityThread.java:5034) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> java.lang.reflect.Method.invokeNative(Native Method) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> java.lang.reflect.Method.invoke(Method.java:515) 12-07 21:46:18.242:
> E/AndroidRuntime(20993):  at
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:611) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> dalvik.system.NativeStart.main(Native Method) 12-07 21:46:18.242:
> E/AndroidRuntime(20993): Caused by: java.lang.NullPointerException
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> com.test.calculator.MainActivity.onCreate(MainActivity.java:34) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> android.app.Activity.performCreate(Activity.java:5241) 12-07
> 21:46:18.242: E/AndroidRuntime(20993):    at
> android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151)
> 12-07 21:46:18.242: E/AndroidRuntime(20993):  ... 11 more 12-07
> 21:46:18.265: I/Process(20993): Sending signal. PID: 20993 SIG: 9
> 12-07 21:46:52.890: D/OpenGLRenderer(21120): Enabling debug mode 0
> 12-07 21:46:53.148: I/Timeline(21120): Timeline: Activity_idle id:
> android.os.BinderProxy@41db95b8 time:61102416 12-07 21:47:22.859:
> I/Timeline(21120): Timeline: Activity_idle id:
> android.os.BinderProxy@41db95b8 time:61132128 12-07 21:51:53.742:
> I/Timeline(21271): Timeline: Activity_idle id:
> android.os.BinderProxy@41db1b50 time:61403009 12-07 21:51:59.390:
> D/AndroidRuntime(21544): Shutting down VM 12-07 21:51:59.390:
> W/dalvikvm(21544): threadid=1: thread exiting with uncaught exception
> (group=0x417cac08) 12-07 21:51:59.390: E/AndroidRuntime(21544): FATAL
> EXCEPTION: main 12-07 21:51:59.390: E/AndroidRuntime(21544): Process:
> com.test.calculator, PID: 21544 12-07 21:51:59.390:
> E/AndroidRuntime(21544): java.lang.RuntimeException: Unable to start
> activity
> ComponentInfo{com.test.calculator/com.test.calculator.MainActivity}:
> java.lang.NullPointerException 12-07 21:51:59.390:
> E/AndroidRuntime(21544):  at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2187)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> android.app.ActivityThread.access$800(ActivityThread.java:138) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> android.os.Handler.dispatchMessage(Handler.java:102) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> android.os.Looper.loop(Looper.java:136) 12-07 21:51:59.390:
> E/AndroidRuntime(21544):  at
> android.app.ActivityThread.main(ActivityThread.java:5034) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> java.lang.reflect.Method.invokeNative(Native Method) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> java.lang.reflect.Method.invoke(Method.java:515) 12-07 21:51:59.390:
> E/AndroidRuntime(21544):  at
> com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> com.android.internal.os.ZygoteInit.main(ZygoteInit.java:611) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> dalvik.system.NativeStart.main(Native Method) 12-07 21:51:59.390:
> E/AndroidRuntime(21544): Caused by: java.lang.NullPointerException
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> com.test.calculator.MainActivity.onCreate(MainActivity.java:34) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> android.app.Activity.performCreate(Activity.java:5241) 12-07
> 21:51:59.390: E/AndroidRuntime(21544):    at
> android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  at
> android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151)
> 12-07 21:51:59.390: E/AndroidRuntime(21544):  ... 11 more 12-07
> 21:52:02.109: I/Process(21544): Sending signal. PID: 21544 SIG: 9

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调用setContentViewR.layout.activity_main；在尝试检索UI元素之前，即在super.onCreate…setContentViewR.layout.activity\u main之后；super.onCreatesavedInstanceState；坠毁。。。