java - 致命异常 : main and Nullpointer

Question

我已经遇到这个非常烦人的问题几天了，而且我似乎无法完全解决它。我正在尝试打开 .csv 文件，因此我将其导入到项目的 res/raw/ 文件夹中。然后我尝试通过 getResources() 方法打开并读取它，这正是我得到 NullPointerException 的地方。下面是读取文件并用可用行填充数组的方法。

这是我的 Activity，我从 Words 类创建一个对象 newwords，然后我想调用 PlayWithRawFiles( ) 类 Words 中的方法。

public class Swear_Activity extends Activity implements OnInitListener, OnClickListener {

    private Words newwords;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_swear);
    }
    public void onClick(View view){
        try {
            newwords.PlayWithRawFiles();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            System.out.println("greshka");
            e.printStackTrace();
        }
    }
}

现在这是我收到错误的类

public class Words{

    public Word[] wordsArray;
    private String locale = "de";
    
    public Words(String locale) {
        if (locale != null ) {
            this.locale = locale;
        }
    }
    
    Context c;
    public void PlayWithRawFiles() throws IOException  {
        String str="";
        StringBuffer buf = new StringBuffer();          
        int i = 0;
        InputStream is = c.getResources().openRawResource(R.raw.est);
        BufferedReader reader = null;
        try{
            if (is != null) reader = new BufferedReader(new InputStreamReader(is));
        }
        catch(Exception e) {
            System.out.println ("ss");
            e.printStackTrace();
        }
            
        if (is!=null) {                         
            while ((str = reader.readLine()) != null) { 
                Word wd = new Word(1,"str");
                this.wordsArray[i] = wd;
                i++;
            }               
        }       
        is.close();
    }
}

这是 Word 类

public class Word {
    private int type;
    private String data;

    public Word(int type, String data){
        this.type = type;
        this.data=data;
    }

    public int getType(){
        return this.type;
    }
    public String getData(){
        return this.data;
    }
}

这是堆栈跟踪

07-10 13:28:58.558: E/AndroidRuntime(647): FATAL EXCEPTION: main

07-10 13:28:58.558: E/AndroidRuntime(647): java.lang.NullPointerException

07-10 13:28:58.558: E/AndroidRuntime(647): at de.android.swearapp.Swear_Activity.onClick(Swear_Activity.java:32)

07-10 13:28:58.558: E/AndroidRuntime(647): at >android.view.View.performClick(View.java:2408)

07-10 13:28:58.558: E/AndroidRuntime(647): at android.view.View$PerformClick.run(View.java:8816)

07-10 13:28:58.558: E/AndroidRuntime(647): at android.os.Handler.handleCallback(Handler.java:587)

07-10 13:28:58.558: E/AndroidRuntime(647): at android.os.Handler.dispatchMessage(Handler.java:92)

07-10 13:28:58.558: E/AndroidRuntime(647): at android.os.Looper.loop(Looper.java:123)

07-10 13:28:58.558: E/AndroidRuntime(647): at android.app.ActivityThread.main(ActivityThread.java:4627)

07-10 13:28:58.558: E/AndroidRuntime(647): at java.lang.reflect.Method.invokeNative(Native Method)

07-10 13:28:58.558: E/AndroidRuntime(647): at java.lang.reflect.Method.invoke(Method.java:521)

07-10 13:28:58.558: E/AndroidRuntime(647): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)

07-10 13:28:58.558: E/AndroidRuntime(647): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)

07-10 13:28:58.558: E/AndroidRuntime(647): at dalvik.system.NativeStart.main(Native Method)

我做错了什么？我真的被这个问题困住了。预先感谢您!

Answer 1

您从未实例化 newwords 对象。

您需要在 onCreate 中的 onClick 之前添加类似的内容

newwords = new Words("");