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我是編碼方面的新手,因此任何幫助都將不勝感激。我有一個Android手機上的文本文件,其中包含幾個字符串,基本上是數字 - 「553955765.50 272 272 272 200.1 100 7391 22 22 10 53」如何將空格的雙精度字符串更改爲我可以使用的雙精度數組
我已經設法從手機上讀取文件,但每個一次我試圖數字這個字符串轉換成double數組中,我得到一個錯誤說
java.lang.NumberFormatException:無效的雙: 「553955765.50 272 272 272 200.1 100 7391 22 22 10 53」
這是我的代碼塊;任何幫助將不勝感激 - 再次我對編碼非常陌生,所以如果你能解釋解決方案,我會永遠感激!
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
File sdcard = Environment.getExternalStorageDirectory();
ArrayList aList = new ArrayList();
//Get the text file
File file = new File(sdcard, "test.txt");
//Read text from file
StringBuilder text = new StringBuilder();
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
String[] tokens = line.split(" ");
double[] ary = new double[tokens.length];
for (int n = 0; n < tokens.length; n++){
ary[n] = Double.parseDouble(tokens[n]);
}
}
br.close();
} catch (IOException e) {
}
//Find the view by its id
TextView tv = (TextView) findViewById(R.id.text_view);
//Set the text
tv.setText(text.toString());
}
}
以下是完整的錯誤:
FATAL EXCEPTION: main
Process: usd.read_text, PID: 32434 java.lang.RuntimeException: Unable to start activity ComponentInfo{usd.read_text/usd.read_text.MainActivity}: java.lang.NumberFormatException: Invalid double: "553955765.50 272 272 272 200.1 100 7391 22 22 10 53"
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2521)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2595)
at android.app.ActivityThread.access$800(ActivityThread.java:178)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1470)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5631)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
Caused by: java.lang.NumberFormatException: Invalid double: "553955765.50 272 272 272 200.1 100 7391 22 22 10 53"
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.initialParse(StringToReal.java:164)
at java.lang.StringToReal.parseDouble(StringToReal.java:282)
at java.lang.Double.parseDouble(Double.java:301)
at usd.read_text.MainActivity.onCreate(MainActivity.java:43)
at android.app.Activity.performCreate(Activity.java:6092)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1112)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2468)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2595)
at android.app.ActivityThread.access$800(ActivityThread.java:178)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1470)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5631)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
看起來你很好。問題在哪裏 –
我無法用給定的輸入字符串使用此代碼重現問題。這是實際的錯誤?如果沒有,請發佈完整的實際錯誤。當你這樣做時,確保你沒有試圖解析任何空的字符串,並確保文件實際上是通過空格來分隔數字而不是製表符或其他東西。 – Dewick47
A)不要忽略IO異常。 B)消息非常清楚「1 2 3」不能被解析爲單個數字。你在這裏展示的代碼有些腥意... – GhostCat