按钮不创建文件，按下时显示电子邮件提供程序选项菜单

Question

我创建了一个按钮，创建一个文件，然后将其作为附件发送到电子邮件，它从一个文本视图中抓取文本，将其保存到. txt并发送。一个小的电子邮件服务选项选择器也应该出现。如果文件路径尚未存在，则该代码将用于创建文件路径。这个代码是在一个常规的活动中的oncreate方法之上。我一直在logcat中得到这个（由（-

-->08-06 12:53:01.019  18432-18432/com.example.adrian.trucktracker W/System.err﹕ java.io.IOException: open failed: ENOENT (No such file or directory)<---
08-06 12:53:01.019  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.io.File.createNewFile(File.java:946)
08-06 12:53:01.019  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at com.example.adrian.trucktracker.Locator.clickedUpdate(Locator.java:76)
08-06 12:53:01.019  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
08-06 12:53:01.019  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.view.View$1.onClick(View.java:3860)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.view.View.performClick(View.java:4480)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.view.View$PerformClick.run(View.java:18686)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:733)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.os.Looper.loop(Looper.java:157)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5872)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at libcore.io.Posix.open(Native Method)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ at java.io.File.createNewFile(File.java:939)
08-06 12:53:01.029  18432-18432/com.example.adrian.trucktracker W/System.err﹕ ... 15 more

我的代码：

    public void clickedUpdate(View view)
        {
            TextView dLong = (TextView) findViewById (R.id.textLong);
            TextView dLat = (TextView) findViewById (R.id.textLat);
            String dataLat = dLat.getText().toString();
            String dataLong = dLong.getText().toString();
            boolean UpdateResume;
            if(!(dataLat.equals("") && !(dataLong.equals(""))))
            {
                UpdateResume = true;
            }
            else
            {
                UpdateResume = false;
            }
            TelephonyManager telephonemanager =(TelephonyManager)this.getSystemService(Context.TELEPHONY_SERVICE);
            String PhoneNumber = telephonemanager.getLine1Number();
            File DataDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+File.separator+"/LocationData");
            if(!DataDir.exists())
            {
                try
                {
                    DataDir.mkdir();
                }
                catch (Exception e)
                {
                    e.printStackTrace();
                }
            }
            File Data = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+File.separator+"data" + File.separator+"Locationer.txt");
            String datapath = Data + ""
            if(!Data.exists())
            {
                try {
line 76 ---->    Data.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                while (UpdateResume = true)
                {
    if (Data.exists())
                    {
                        try
                        {
                            FileWriter fileWriter = new FileWriter(Data);
                            BufferedWriter bfWriter = new BufferedWriter(fileWriter);
                            bfWriter.write(PhoneNumber + "," + dataLat + "," + dataLong);
                            bfWriter.close();
                        }
                        catch (IOException e)
                        {
                            e.printStackTrace();
                        }
                    }
                    break;
                }
            }
            Intent emailintent = new Intent(Intent.ACTION_SEND);
            emailintent.setType("text/plain");
            emailintent.putExtra(Intent.EXTRA_EMAIL, new String[]{"[e-mail]"});
            emailintent.putExtra(Intent.EXTRA_SUBJECT, "Data");
            emailintent.putExtra(Intent.EXTRA_TEXT, "Hello World!");
            File root = Environment.getExternalStorageDirectory();
            String DataAttachment = "Android/data/Locationer.txt";
            File filer = new File(root, DataAttachment);
            if (!filer.exists() || filer.canRead())
            {
                return;
            }
            Uri uri = Uri.fromFile(filer);
            emailintent.putExtra(Intent.EXTRA_STREAM, uri);
            startActivity(Intent.createChooser(emailintent, "Choose an Email provider"));
    }

Answer 1

一些细节似乎是相关的：

首先检查dir是否存在：

        File DataDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+File.separator+"/LocationData");
        if(!DataDir.exists())
        {
            try
            {
                DataDir.mkdir();
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }

根据留档，不需要你的try{}cat（异常e）{}。您只需要检查目录是否实际存在。还有一个额外的问题，您似乎创建了另一个子目录的子目录。因此，您可能希望将其交换为mkdirs（）。

之后，如果文件不存在，则尝试创建该文件

   try {
line 76 ---->    Data.createNewFile();
   } catch (IOException e) {
           e.printStackTrace();
   }

看看这个方法的留档。你可能会注意到它告诉你

这种方法通常不有用。要创建临时文件，请改用createTempFile（字符串，字符串）。要读取/写入文件，请使用FileInputStream、FileOutputStream或RandomAccessFile，所有这些都可以创建文件。

但是，如果您已经包含了适当的权限，我上面建议的更改可能会有助于您的代码正常工作。