Android:应用程序在一台设备上运行良好，但在另一台设备上运行不正常

Question

我遇到了一个问题，我的应用程序在我的 Galaxy Tab 7.7 GT-P6800 上运行良好，我将其用于调试目的，并在我的 Galaxy Pocket 上使用它运行并创建一个文件夹来放置文件，甚至接受输入和所有这些东西，但它没有创建文件。我正在 eclipse 中开发，应用程序的构建 SDK 是 Android 2.3.3 (API 10)。

应用代码如下，找不到问题所在...

package com.android.app1;

public class MainActivity extends Activity {

//Timestamp for file name e.g. Data_7-19-2012
SimpleDateFormat s1 = new SimpleDateFormat("MM-dd-yyyy_hh:mm:ss");
final String format1 = s1.format(new Date()); 

final public String FileName = "Data_"+format1+".csv";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final EditText addbarcode = (EditText) findViewById(R.id.editText1); 
addbarcode.setOnKeyListener(new OnKeyListener()
    {
        public boolean onKey(View v, int keyCode, KeyEvent event)
        {
            if (event.getAction() == KeyEvent.ACTION_DOWN)
            {
                switch (keyCode)
                {
                    case KeyEvent.KEYCODE_ENTER:

                        //to get Timestamp
                        SimpleDateFormat s = new SimpleDateFormat("MM-dd-yyyy hh:mm:ss");
                        String format = s.format(new Date());

                        //get barcode in a variable
                        Editable barcode = addbarcode.getText();

                        final String DATASTRING = new String(""+barcode+","+format+"");



                        try
                        {
                            File root = new File(Environment.getExternalStorageDirectory(), "BarcodeData");

                            if (!root.exists()) {
                                root.mkdirs();

                            }

                        //Showing file directory
                        TextView etDir= (TextView)findViewById(R.id.textView1);
                            etDir.setText(root.toString());


                            File gpxfile = new File(root, FileName);

                            BufferedWriter bW;

                            bW = new BufferedWriter(new FileWriter(gpxfile, true));
                            bW.write(DATASTRING);
                            bW.newLine();
                            bW.flush();
                            bW.close();

                        }
                        catch(IOException e)
                        {
                             e.printStackTrace();
                        }
            String readString = new String(DATASTRING);
                    TextView etData= (TextView)findViewById(R.id.textView2);

                    etData.setText(readString);

                        //Clear the editview for new entries
                        addbarcode.setText("");   
                      return true;
                    default:
                        break;
                }
            }
            return false;
        }
    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.send:

            final File dir = getFilesDir();

            final File shareFile = new File(dir, FileName);
            Uri u1  =   null;
            u1  =   Uri.fromFile(shareFile);

            Intent sendIntent = new Intent(Intent.ACTION_SEND);
            sendIntent.putExtra(Intent.EXTRA_SUBJECT, "Person Details");
            sendIntent.putExtra(Intent.EXTRA_STREAM, u1);
            sendIntent.setType("text/csv");
            startActivity(sendIntent);
            break;
    }
    return true;
}
}

我什至添加了必需的权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

甚至可以从项目属性中设置 Java Build Path 属性。

Answer 1

参见 getExternalStorageDirectory()文档。

Gets the Android external storage directory. This directory may not currently be accessible if it has been mounted by the user on their computer, has been removed from the device, or some other problem has happened. You can determine its current state with getExternalStorageState().

在访问它之前检查它是否为 null。