BackupDataInput Class

Definition

[Android.Runtime.Register("android/app/backup/BackupDataInput", DoNotGenerateAcw=true)]
public class BackupDataInput : Java.Lang.Object

[<Android.Runtime.Register("android/app/backup/BackupDataInput", DoNotGenerateAcw=true)>]
type BackupDataInput = class
    inherit Object

Inheritance

Object

Object

BackupDataInput

Attributes

RegisterAttribute

Remarks

Provides the structured interface through which a BackupAgent reads information from the backup data set, via its BackupAgent#onRestore(BackupDataInput, int, android.os.ParcelFileDescriptor) onRestore() method. The data is presented as a set of "entities," each representing one named record as previously stored by the agent's BackupAgent#onBackup(ParcelFileDescriptor,BackupDataOutput,ParcelFileDescriptor) onBackup() implementation. An entity is composed of a descriptive header plus a byte array that holds the raw data saved in the remote backup.

The agent must consume every entity in the data stream, otherwise the restored state of the application will be incomplete. <h3>Example</h3>

A typical BackupAgent#onRestore(BackupDataInput,int,ParcelFileDescriptor) onRestore() implementation might be structured something like this:

public void onRestore(BackupDataInput data, int appVersionCode,
                                  ParcelFileDescriptor newState) {
                while (data.readNextHeader()) {
                    String key = data.getKey();
                    int dataSize = data.getDataSize();

                    if (key.equals(MY_BACKUP_KEY_ONE)) {
                        // process this kind of record here
                        byte[] buffer = new byte[dataSize];
                        data.readEntityData(buffer, 0, dataSize); // reads the entire entity at once

                        // now 'buffer' holds the raw data and can be processed however
                        // the agent wishes
                        processBackupKeyOne(buffer);
                    } else if (key.equals(MY_BACKUP_KEY_TO_IGNORE) {
                        // a key we recognize but wish to discard
                        data.skipEntityData();
                    } // ... etc.
               }
            }

Java documentation for android.app.backup.BackupDataInput.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to