我的应用程序一直停止工作，直到最后一次测试。这是我的Logcat， 在我工作之前我正在使用它，但现在我没有工作
04-13 19:44:49.949: E/AndroidRuntime(12824): FATAL EXCEPTION: main
04-13 19:44:49.949: E/AndroidRuntime(12824): Process: com.aswinajay.rubixcubealgorithms, PID: 12824
04-13 19:44:49.949: E/AndroidRuntime(12824): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.aswinajay.rubixcubealgorithms/com.aswinajay.rubixcubealgorithms.MainActivity}: java.lang.NullPointerException
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.os.Handler.dispatchMessage(Handler.java:102)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.os.Looper.loop(Looper.java:136)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-13 19:44:49.949: E/AndroidRuntime(12824): at java.lang.reflect.Method.invokeNative(Native Method)
04-13 19:44:49.949: E/AndroidRuntime(12824): at java.lang.reflect.Method.invoke(Method.java:515)
04-13 19:44:49.949: E/AndroidRuntime(12824): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-13 19:44:49.949: E/AndroidRuntime(12824): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-13 19:44:49.949: E/AndroidRuntime(12824): at dalvik.system.NativeStart.main(Native Method)
04-13 19:44:49.949: E/AndroidRuntime(12824): Caused by: java.lang.NullPointerException
04-13 19:44:49.949: E/AndroidRuntime(12824): at com.aswinajay.rubixcubealgorithms.MainActivity.onCreate(MainActivity.java:35)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.Activity.performCreate(Activity.java:5231)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-13 19:44:49.949: E/AndroidRuntime(12824): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
04-13 19:44:49.949: E/AndroidRuntime(12824): ... 11 more
这是我的班级档案，请帮帮我
package com.aswinajay.rubixcubealgorithms;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.*;
public class MainActivity extends Activity implements OnClickListener {
Button new_game_button;
Button continue_button;
Button about_button;
Button exit_button;
Button Notation_button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
View continue_Button = findViewById(R.id.continue_button);
continue_Button.setOnClickListener(this);
View new_game_Button = findViewById(R.id.new_game_button);
new_game_Button.setOnClickListener(this);
View about_Button = findViewById(R.id.about_button);
about_Button.setOnClickListener(this);
View exit_Button = findViewById(R.id.exit_button);
exit_Button.setOnClickListener(this);
View Notation_button = findViewById(R.id.Notation_button);
Notation_button.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId()){
case R.id.new_game_button:
Intent intent = new Intent(MainActivity.this,PLL.class);
startActivity(intent);
break;
case R.id.continue_button:
Intent intent1 = new Intent(MainActivity.this,F2L.class);
startActivity(intent1);
break;
case R.id.about_button:
Intent intent4 = new Intent(MainActivity.this,OLL.class);
startActivity(intent4);
break;
case R.id.exit_button:
Intent intent3 = new Intent(MainActivity.this,About.class);
startActivity(intent3);
break;
case R.id.Notation_button:
Intent intent5 = new Intent(MainActivity.this,Notation.class);
startActivity(intent5);
break;
}}
@Override
public void onBackPressed() {
{
super.onBackPressed();
this.finish();
Intent intent = new Intent (this,MainActivity.class);
startActivity(intent);
finish();
super.onBackPressed();
}
}
}
但是代码是正确的我认为如此！ 这是我的清单
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.aswinajay.rubixcubealgorithms"
android:versionCode="1"
android:versionName="1.0" >
<supports-screens
android:largeScreens="true"
android:normalScreens="true"
android:smallScreens="true"
android:xlargeScreens="true" />
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.aswinajay.rubixcubealgorithms.MainActivity"
android:label="@string/app_name"
android:screenOrientation="landscape" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="About"
android:label="@string/title_activity_about_main"
android:screenOrientation="landscape"
android:theme="@android:style/Theme.Dialog">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.About"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="F2L"
android:label="@string/title_activity_f2l_main"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.F2L"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="OLL"
android:label="@string/title_activity_oll_main"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.OLL"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="PLL"
android:label="@string/title_activity_pll_main"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.PLL"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="Basepll"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.Basepll"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="Baseoll"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.Baseoll"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="Basef2l"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.Basef2l"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
<activity
android:name="Notation"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="com.example.rubikscubealgorithms.Notation"></action>
<category android:name="android.intent.category.DEFAULT" >
</category>
</intent-filter>
</activity>
</application>
答案 0 :(得分：1)
试试这个..
以下更改
View continue_Button = findViewById(R.id.continue_button);
continue_Button.setOnClickListener(this);
View new_game_Button = findViewById(R.id.new_game_button);
new_game_Button.setOnClickListener(this);
View about_Button = findViewById(R.id.about_button);
about_Button.setOnClickListener(this);
View exit_Button = findViewById(R.id.exit_button);
exit_Button.setOnClickListener(this);
View Notation_button = findViewById(R.id.Notation_button);
Notation_button.setOnClickListener(this);
作为
continue_Button = (Button) findViewById(R.id.continue_button);
continue_Button.setOnClickListener(this);
new_game_Button = (Button) findViewById(R.id.new_game_button);
new_game_Button.setOnClickListener(this);
about_Button = (Button) findViewById(R.id.about_button);
about_Button.setOnClickListener(this);
exit_Button = (Button) findViewById(R.id.exit_button);
exit_Button.setOnClickListener(this);
Notation_button = (Button) findViewById(R.id.Notation_button);
Notation_button.setOnClickListener(this);
答案 1 :(得分：1)
你应该改变这个
View continue_Button = findViewById(R.id.continue_button);
continue_Button.setOnClickListener(this);
View new_game_Button = findViewById(R.id.new_game_button);
new_game_Button.setOnClickListener(this);
View about_Button = findViewById(R.id.about_button);
about_Button.setOnClickListener(this);
View exit_Button = findViewById(R.id.exit_button);
exit_Button.setOnClickListener(this);
View Notation_button = findViewById(R.id.Notation_button);
使用
continue_Button = (Button) findViewById(R.id.continue_button);
continue_Button.setOnClickListener(this);
new_game_Button = (Button) findViewById(R.id.new_game_button);
new_game_Button.setOnClickListener(this);
about_Button = (Button) findViewById(R.id.about_button);
about_Button.setOnClickListener(this);
exit_Button = (Button) findViewById(R.id.exit_button);
exit_Button.setOnClickListener(this);
Notation_button = (Button) findViewById(R.id.Notation_button);
Notation_button.setOnClickListener(this);
您必须投放所有Button。并确保您的activity_main.xml包含所有Buttons