onSyncStatusChange 在 Dropbox Sync API 中被调用两次

Question

我已成功在我的应用中实现了 Dropbox 的 Sync API。这是代码

public class MainActivity extends Activity implements SyncStatusListener
{
    private static final String appKey = "xxxxx";
    private static final String appSecret = "xxx";

    private static final int REQUEST_LINK_TO_DBX = 0;

    private TextView mTestOutput;
    private Button mLinkButton;
    private Button saveButton;
    private EditText txtFile;
    private DbxAccountManager mDbxAcctMgr;

    private static String fileName = "data.txt";

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

        txtFile = ( EditText ) findViewById( R.id.writeFile );
        mTestOutput = (TextView) findViewById(R.id.test_output);
        mLinkButton = (Button) findViewById(R.id.link_button);
        saveButton = (Button) findViewById( R.id.save );

        mLinkButton.setOnClickListener( new OnClickListener()
        {
            @Override 
            public void onClick ( View  view )
            {
                if ( mDbxAcctMgr != null )
                {
                    mDbxAcctMgr.startLink( (Activity)MainActivity.this, REQUEST_LINK_TO_DBX );
                }
            }
        });

        saveButton.setOnClickListener( new OnClickListener()
        {
            @Override 
            public void onClick ( View view )
            {
                SaveFile();   
            }
        });

        mDbxAcctMgr = DbxAccountManager.getInstance(getApplicationContext(), appKey, appSecret);
    }

    @Override
    protected void onResume() 
    {
        super.onResume();
        if (mDbxAcctMgr.hasLinkedAccount()) 
        {
            loadFileFromDropbox();
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) 
    {
        if ( requestCode == REQUEST_LINK_TO_DBX ) 
        {
            if (resultCode == Activity.RESULT_OK) 
            {
                loadFileFromDropbox();
            } 
            else 
            {
                mTestOutput.setText("Link to Dropbox failed or was cancelled.");
            }
        } 
        else 
        {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }

    private void loadFileFromDropbox()
    {
        try
        {
            DbxPath testPath = new DbxPath( DbxPath.ROOT, fileName );

            // Create DbxFileSystem for synchronized file access.
            DbxFileSystem dbxFs = DbxFileSystem.forAccount(mDbxAcctMgr.getLinkedAccount());

            if (dbxFs.isFile(testPath)) 
            {
                String resultData;
                DbxFile testFile = dbxFs.open(testPath);

                try 
                {
                    resultData = testFile.readString();
                } 
                finally 
                {
                    testFile.close();
                }
                mTestOutput.append("\nRead file '" + testPath + "' and got data:\n    " + resultData);
                txtFile.setText(resultData);
            } 
            else if (dbxFs.isFolder(testPath)) 
            {
                mTestOutput.append("'" + testPath.toString() + "' is a folder.\n");
            }
        }
        catch ( Exception e )
        {
            System.out.println ( "loadFileFromDropbox Error : " + e.toString() );
        }
    }

    private void SaveFile()
    {
        try
        {
            DbxPath testPath = new DbxPath( DbxPath.ROOT, fileName );
            DbxFileSystem dbxFs = DbxFileSystem.forAccount(mDbxAcctMgr.getLinkedAccount());

            // Create a test file only if it doesn't already exist.
            String fileData = txtFile.getText().toString().trim();

            dbxFs.addSyncStatusListener(this);

            if (!dbxFs.exists(testPath)) 
            {
                DbxFile testFile = dbxFs.create(testPath);
                try 
                {
                    if ( !fileData.equals( "" ) )
                    {
                        testFile.writeString( fileData );
                    }
                } 
                finally 
                {
                    testFile.close();
                }
                mTestOutput.append("\nCreated new file '" + testPath + "'.\n");
            }
            else
            {
                DbxFile testFile = dbxFs.open( testPath );
                try 
                {
                    if ( !fileData.equals( "" ) )
                    {
                        testFile.writeString( fileData );
                    }
                } 
                finally 
                {
                    testFile.close();
                }
            }
        }
        catch ( Exception e )
        {
            System.out.println ( "Save Error : " + e.toString() );
        }
    }

    @Override
    public void onSyncStatusChange( DbxFileSystem fs ) 
    {
        try
        {
            if ( fs.getSyncStatus() != null )
            {
                loadFileFromDropbox();
            }
        }
        catch ( Exception e )
        {
            System.out.println ( "OK " + e.toString() );
        }
    }
}

我有一个 EditText，它将加载文件的内容。我可以添加/更新其内容并将其保存在我的保管箱帐户中。保存后多次调用onSyncStatusChange() 方法。

为什么会这样？

Answer 1

如果您从onSyncStatusChange 记录实际状态，我想每次都会发生什么变化。

我的猜测是当状态更改为上传时调用一次，然后在上传完成时再次调用。所以如果你登录fs.getSyncStatus().uploading.inProgress，你会看到它翻转为真，然后又变回假，这是有道理的。