Android应用程式无法运作，当机

Question

As soon as this java file is opened, application crashes. Please help me , I was just cleaning the app, I made new class baconAndEggs to which I shifted various instances and I implemented actionlistener and made separate switch cases for both buttons,before that everything was working fine.

package com.example.testing;

import java.util.Random;

import android.annotation.TargetApi;
import android.app.Activity;
import android.graphics.Color;
import android.os.Build;
import android.os.Bundle;
import android.text.InputType;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.ToggleButton;

public class TextPlay extends Activity implements View.OnClickListener{

    Button chkCmd;
    ToggleButton passTog;
    EditText input;
    TextView display;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.text);

        baconAndEggs();
        passTog.setOnClickListener(this);
        chkCmd.setOnClickListener(this);
    }
        private void baconAndEggs() {
        // TODO Auto-generated method stub
                chkCmd = (Button) findViewById (R.id.bResults);
                ToggleButton passTog = (ToggleButton) findViewById (R.id.tbPassword);
                EditText input =(EditText) findViewById (R.id.etCommands);
                TextView display = (TextView) findViewById (R.id.tvResults);
            }
    @TargetApi(Build.VERSION_CODES.HONEYCOMB) @Override
    public void onClick(View view) {
        // TODO Auto-generated method stub
        switch(view.getId()){
        case R.id.bResults:
            String check = input.getText().toString();
            display.setText(check);
            if  (check.contentEquals("left")){
                display.setGravity(Gravity.LEFT);
                }
            else if(check.contentEquals("right")){
                display.setGravity(Gravity.RIGHT);
                }
            else if(check.contentEquals("center")){
                display.setGravity(Gravity.CENTER);
                }
            else if(check.contentEquals("blue")){
                display.setTextColor(Color.BLUE);
            }
            else if(check.contains("WTF")){
                Random crazy = new Random ();
                display.setText("WTF!!!!!");
                display.setTextSize(crazy.nextInt(75));
                display.setTextColor(crazy.nextInt(265));
                switch(crazy.nextInt(3)){
                case 0:
                    display.setGravity(Gravity.CENTER);
                    break;
                case 1:
                    display.setGravity(Gravity.RIGHT);
                    break;
                case 2:
                    display.setGravity(Gravity.LEFT);
                    break;
                }
        }
            else{
                display.setText("invalid");
                display.setGravity(Gravity.CENTER);
                display.setTextColor(Color.WHITE);
            }

            break;
          case R.id.tbPassword :

                if(passTog.isChecked()){
                        input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_NUMBER_VARIATION_PASSWORD);
                }
                else{
                    input.setInputType(InputType.TYPE_CLASS_TEXT);
                    }

            break;

    }       

    }
}   

Error in logcat i am getting is

03-25 14:29:40.928: D/dalvikvm(1047): GC_FOR_ALLOC freed 72K, 5% free 3033K/3180K, paused 114ms, total 122ms
03-25 14:29:41.048: I/dalvikvm-heap(1047): Grow heap (frag case) to 6.284MB for 3414416-byte allocation
03-25 14:29:41.148: D/dalvikvm(1047): GC_FOR_ALLOC freed 2K, 3% free 6364K/6516K, paused 98ms, total 98ms
03-25 14:29:43.218: E/MediaPlayer(1047): Should have subtitle controller already set
03-25 14:29:43.818: D/gralloc_goldfish(1047): Emulator without GPU emulation detected.
03-25 14:29:49.388: D/dalvikvm(1047): GC_FOR_ALLOC freed 12K, 2% free 6573K/6660K, paused 132ms, total 141ms
03-25 14:29:51.628: I/Choreographer(1047): Skipped 50 frames!  The application may be doing too much work on its main thread.
03-25 14:29:54.168: I/Choreographer(1047): Skipped 55 frames!  The application may be doing too much work on its main thread.
03-25 14:29:56.478: D/dalvikvm(1047): GC_FOR_ALLOC freed 18K, 2% free 7782K/7876K, paused 53ms, total 58ms
03-25 14:29:56.838: D/AndroidRuntime(1047): Shutting down VM
03-25 14:29:56.838: W/dalvikvm(1047): threadid=1: thread exiting with uncaught exception (group=0xb1a47b90)
03-25 14:29:56.878: E/AndroidRuntime(1047): FATAL EXCEPTION: main
03-25 14:29:56.878: E/AndroidRuntime(1047): Process: com.example.testing, PID: 1047
03-25 14:29:56.878: E/AndroidRuntime(1047): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testing/com.example.testing.TextPlay}: java.lang.NullPointerException
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread.access$700(ActivityThread.java:135)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.os.Handler.dispatchMessage(Handler.java:102)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.os.Looper.loop(Looper.java:137)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread.main(ActivityThread.java:4998)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at java.lang.reflect.Method.invokeNative(Native Method)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at java.lang.reflect.Method.invoke(Method.java:515)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at dalvik.system.NativeStart.main(Native Method)
03-25 14:29:56.878: E/AndroidRuntime(1047): Caused by: java.lang.NullPointerException
03-25 14:29:56.878: E/AndroidRuntime(1047):     at com.example.testing.TextPlay.onCreate(TextPlay.java:29)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.Activity.performCreate(Activity.java:5243)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
03-25 14:29:56.878: E/AndroidRuntime(1047):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
03-25 14:29:56.878: E/AndroidRuntime(1047):     ... 11 more
03-25 14:30:05.018: I/Process(1047): Sending signal. PID: 1047 SIG: 9
03-25 14:32:29.158: D/dalvikvm(1104): GC_FOR_ALLOC freed 35K, 4% free 3033K/3144K, paused 43ms, total 48ms
03-25 14:32:29.188: I/dalvikvm-heap(1104): Grow heap (frag case) to 6.284MB for 3414416-byte allocation
03-25 14:32:29.238: D/dalvikvm(1104): GC_FOR_ALLOC freed 2K, 2% free 6364K/6480K, paused 44ms, total 44ms
03-25 14:32:29.708: E/MediaPlayer(1104): Should have subtitle controller already set
03-25 14:32:30.028: D/gralloc_goldfish(1104): Emulator without GPU emulation detected.
03-25 14:32:35.048: D/dalvikvm(1104): GC_FOR_ALLOC freed 13K, 2% free 6575K/6660K, paused 73ms, total 75ms
03-25 14:32:35.828: I/Choreographer(1104): Skipped 38 frames!  The application may be doing too much work on its main thread.
03-25 14:32:42.318: D/dalvikvm(1104): GC_FOR_ALLOC freed 18K, 2% free 7784K/7876K, paused 53ms, total 66ms
03-25 14:32:55.058: D/AndroidRuntime(1104): Shutting down VM
03-25 14:32:55.058: W/dalvikvm(1104): threadid=1: thread exiting with uncaught exception (group=0xb1a47b90)
03-25 14:32:55.118: E/AndroidRuntime(1104): FATAL EXCEPTION: main
03-25 14:32:55.118: E/AndroidRuntime(1104): Process: com.example.testing, PID: 1104
03-25 14:32:55.118: E/AndroidRuntime(1104): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testing/com.example.testing.TextPlay}: java.lang.NullPointerException
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread.access$700(ActivityThread.java:135)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.os.Handler.dispatchMessage(Handler.java:102)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.os.Looper.loop(Looper.java:137)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread.main(ActivityThread.java:4998)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at java.lang.reflect.Method.invokeNative(Native Method)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at java.lang.reflect.Method.invoke(Method.java:515)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at dalvik.system.NativeStart.main(Native Method)
03-25 14:32:55.118: E/AndroidRuntime(1104): Caused by: java.lang.NullPointerException
03-25 14:32:55.118: E/AndroidRuntime(1104):     at com.example.testing.TextPlay.onCreate(TextPlay.java:31)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.Activity.performCreate(Activity.java:5243)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
03-25 14:32:55.118: E/AndroidRuntime(1104):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
03-25 14:32:55.118: E/AndroidRuntime(1104):     ... 11 more
03-25 14:32:59.768: I/Process(1104): Sending signal. PID: 1104 SIG: 9

Answer 1

It's a scope issue.

Inside baconAndEggs() you declare and assign some variables:

ToggleButton passTog = (ToggleButton) findViewById (R.id.tbPassword);
EditText input =(EditText) findViewById (R.id.etCommands);
TextView display = (TextView) findViewById (R.id.tvResults);

Once baconAndEggs() exits, those variables no longer exist.

Considering you declared all of these as class members, you probably meant:

passTog = (ToggleButton) findViewById (R.id.tbPassword);
input =(EditText) findViewById (R.id.etCommands);
display = (TextView) findViewById (R.id.tvResults);

Answer 2

You have:

ToggleButton passTog = (ToggleButton) findViewById (R.id.tbPassword);

in your function baconAndEggs . Make that

passTog = (ToggleButton) findViewById (R.id.tbPassword);

Otherwise it becomes a local variable.