從Android中的資產文件讀取

Question

我正在開發一個Hangman游戲，以自學Android開發。 我已經在PC上用Java完成了所有這些工作，並且運行良好。 我使用的是Android Studio 2.1，並且顯示器不斷向我拋出錯誤，我看不清自己在看什么！

我苦苦掙扎的部分是讓它從資產中的“ WordsDoc”文件中讀取。 我得到的代碼是：

編輯2

到目前為止，應用程序的所有代碼（確實不多！）

    public class MainActivity extends AppCompatActivity {

    static String strWord = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final TextView theWord = (TextView)
                findViewById(R.id.textViewWord);
        final EditText editTextGuess = (EditText)
                findViewById(R.id.editTextGuess);
        final Button buttonGuess = (Button)
                findViewById(R.id.btnGuess);
        final TextView theIncorrectGuesses = (TextView)
                findViewById(R.id.textViewIncorrectLetters);
        setContentView(R.layout.activity_main);
        alertMessage(this,"ERROR");
        strWord = getTheWord();
        theWord.setText(strWord);
        newGame();
        buttonGuess.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){

                theIncorrectGuesses.setText("ABCDEF");
            }
        });
    }
    public String getTheWord() {

        List<String> lines = new ArrayList<String>();
        BufferedReader reader = null;
        try {
            reader = new BufferedReader(
                    new InputStreamReader(getAssets().open("WordsDoc.txt")));

            // do reading, usually loop until end of file reading
            String mLine;
            while ((mLine = reader.readLine()) != null) {
                //process line
                lines.add(mLine);
            }
            int intLen = 0;
            String[] strWords = lines.toArray(new String[lines.size()]);
            for (String strTemp : strWords){
                intLen ++;
            }
            int intRand = (int)(Math.random()* intLen);
            return strWords[intRand];

        } catch (IOException e) {
            //log the exception
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    //log the exception
                }
            }
        }
        return null;
    }
    public void newGame() {

    }
    public static void alertMessage(Activity a, String errMsg){

        final AlertDialog.Builder builder = new AlertDialog.Builder(a);
        builder.setTitle("Alert Dialog");
        builder.setMessage(errMsg);
        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setNeutralButton("OK", null);
        builder.create().show();
    }
}

編輯3

WordsDoc.txt文件的示例如下：

aardvark
Aarhus
Aaron
... continues 45000 more times

編輯

錯誤：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.xxxx.hangman, PID: 4532
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxxx.hangman/com.xxxx.hangman.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5417)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
    at com.xxxx.hangman.MainActivity.onCreate(MainActivity.java:34)
    at android.app.Activity.performCreate(Activity.java:6237)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5417)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
    05-05 08:44:32.994 4532-4532/com.xxxx.hangman I/Process: Sending signal. PID: 4532 SIG: 9

Answer 1

嘗試打開帶有擴展名的文件：

    BufferedReader reader = null;
    try {
        reader = new BufferedReader(
                new InputStreamReader(getAssets().open("WordsDoc.txt")))
      ...

編輯：我的代碼的解決方案：

您正在嘗試在setContentView（R.layout.activity_main）之前訪問視圖，這就是視圖為空的原因。

把這一行：

setContentView(R.layout.activity_main);

在此之后：

 super.onCreate(savedInstanceState);

在您的MainActivity中。 像這樣：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // the rest goes here