java.lang.RuntimeException异常，请大神赐教！！！

Question

11-18 09:39:51.281 19604-19604/com.example.admin.emotion E/AndroidRuntime: FATAL EXCEPTION: main
                                                                           Process: com.example.admin.emotion, PID: 19604
                                                                           java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.admin.emotion/com.example.admin.emotion.MainFragment}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2793)
                                                                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864)
                                                                               at android.app.ActivityThread.-wrap12(ActivityThread.java)
                                                                               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:105)
                                                                               at android.os.Looper.loop(Looper.java:156)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:6524)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831)
                                                                            Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                               at com.example.admin.emotion.MainFragment.initView(MainFragment.java:80)
                                                                               at com.example.admin.emotion.MainFragment.onCreate(MainFragment.java:59)
                                                                               at android.app.Activity.performCreate(Activity.java:6910)
                                                                               at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
                                                                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2746)
                                                                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864) 
                                                                               at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                                                                               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567) 
                                                                               at android.os.Handler.dispatchMessage(Handler.java:105) 
                                                                               at android.os.Looper.loop(Looper.java:156) 
                                                                               at android.app.ActivityThread.main(ActivityThread.java:6524) 
                                                                               at java.lang.reflect.Method.invoke(Native Method) 
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941) 
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831) 
出问题的代码：
protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.content_main);
        fragmentManager = getSupportFragmentManager();
        initView();
        setChioceItem(0);
    }    private void initView() {
        firstImage = (ImageView) findViewById(R.id.first_image);
        secondImage = (ImageView) findViewById(R.id.second_image);
        thirdImage = (ImageView) findViewById(R.id.third_image);
        fourthImage = (ImageView) findViewById(R.id.fourth_image);
        firstText = (TextView) findViewById(R.id.first_text);
        secondText = (TextView) findViewById(R.id.second_text);
        thirdText = (TextView) findViewById(R.id.third_text);
        fourthText = (TextView) findViewById(R.id.fourth_text);
        firstLayout = (RelativeLayout) findViewById(R.id.first_layout);
        secondLayout = (RelativeLayout) findViewById(R.id.second_layout);
        thirdLayout = (RelativeLayout) findViewById(R.id.third_layout);
        fourthLayout = (RelativeLayout) findViewById(R.id.fourth_layout);        firstLayout.setOnClickListener(MainFragment.this);
        secondLayout.setOnClickListener(MainFragment.this);
        thirdLayout.setOnClickListener(MainFragment.this);
        fourthLayout.setOnClickListener(MainFragment.this);
    }

Answer 1

NullPointerException  你是不是设置点击的那个控件没有赋予findviewbyid啊？

Answer 2

setOnClickListener的引用view为空，使用时增加判断控件是否为空，或者排查你的流程找到真正的rootcause。

Answer 3

 com.example.admin.emotion.MainFragment.initView(MainFragment.java:80)
80行调用setOnClickListener的对象为空，

Answer 4

1.看代码你都已经findViewById
2.既然能安装说明编译正确
由此可见你要找的id不在content_main这个布局文件中，而在其他的布局文件中
可以到MainFragment.java第80行看是哪个对象，然后到布局文件中搜索一下看是否存在

Answer 5

你的initView的方法写的不对，你看一下Fragment的生命周期，你要使用View应该在onViewCreated之后，onCreate的时候界面还没渲染到window中。