我目前遇到了下载地图的难题。我期望下载的地图文件是移动地图包(.mmpk),但实际上我的下载目录中包含一个package.info文件和一个包含geodatabase和.mmap文件的文件夹,如所示。根据我的理解,我需要一个.mmpk文件才能进行离线使用。
在按照教程步骤操作时,我成功完成了(1)创建离线地图任务,(2)指定参数和(3)检查离线功能。但是在第(4)生成并下载离线地图步骤中,我期望下载的地图文件将是移动地图包(.mmpk),但实际情况却不是这样的。在第(5)打开和使用离线地图步骤中,我能够查看手动传输到设备上的移动地图包(.mmpk)文件的离线地图。我也试图打开并使用下载的(.mmap)文件,但没有地图显示出来。
我的完整代码按步骤如下所示: (1)创建离线地图任务
// Load map from a portal item
final Portal portal = new Portal("http://www.arcgis.com");
final PortalItem webmapItem = new PortalItem(portal, "acc027394bc84c2fb04d1ed317aac674");
// Create map and add it to the view
myMap = new ArcGISMap(webmapItem);
mMapView = (MapView) findViewById(R.id.mapView);
mMapView.setMap(myMap);
// Create task and set parameters
final OfflineMapTask offlineMapTask = new OfflineMapTask(myMap);
(2) 指定参数
// Create default parameters
final ListenableFuture<GenerateOfflineMapParameters> parametersFuture = offlineMapTask.createDefaultGenerateOfflineMapParametersAsync(areaOfInterest);
parametersFuture.addDoneListener(new Runnable() {
@Override
public void run() {
try {
final GenerateOfflineMapParameters parameters = parametersFuture.get();
// Update the parameters if needed
// Limit maximum scale to 5000 but take all the scales above (use 0 as a MinScale)
parameters.setMaxScale(5000);
parameters.setIncludeBasemap(false);
// Set attachment options
parameters.setAttachmentSyncDirection(GenerateGeodatabaseParameters.AttachmentSyncDirection.UPLOAD);
parameters.setReturnLayerAttachmentOption(GenerateOfflineMapParameters.ReturnLayerAttachmentOption.EDITABLE_LAYERS);
// Request the table schema only (existing features won't be included)
parameters.setReturnSchemaOnlyForEditableLayers(true);
// Update the title to contain the region
parameters.getItemInfo().setTitle(parameters.getItemInfo().getTitle() + " (Central)");
// Create new item info
final OfflineMapItemInfo itemInfo = new OfflineMapItemInfo();
// Override thumbnail with the new image based on the extent
final ListenableFuture<Bitmap> exportImageFuture = mMapView.exportImageAsync();
exportImageFuture.addDoneListener(new Runnable() {
@Override
public void run() {
try {
Bitmap mapImage = exportImageFuture.get();
// Scale to thumbnail size
Bitmap thumbnailImage = Bitmap.createScaledBitmap(mapImage, 200, 133, false);
// Convert to byte[]
ByteArrayOutputStream stream = new ByteArrayOutputStream();
thumbnailImage.compress(Bitmap.CompressFormat.JPEG, 50, stream);
byte[] thumbnailBytes = stream.toByteArray();
stream.close();
// Set values to the itemInfo
itemInfo.setThumbnailData(thumbnailBytes);
itemInfo.setTitle("Water network (Central)");
itemInfo.setSnippet(webmapItem.getSnippet()); // Copy from the source map
itemInfo.setDescription(webmapItem.getDescription()); // Copy from the source map
itemInfo.setAccessInformation(webmapItem.getAccessInformation()); // Copy from the source map
itemInfo.getTags().add("Water network");
itemInfo.getTags().add("Data validation");
// Set metadata to parameters
parameters.setItemInfo(itemInfo);
} catch (Exception e) {
e.printStackTrace();
}
}
});
(3)检查离线功能
final ListenableFuture<OfflineMapCapabilities> offlineMapCapabilitiesFuture =
offlineMapTask.getOfflineMapCapabilitiesAsync(parameters);
offlineMapCapabilitiesFuture.addDoneListener(new Runnable() {
@Override
public void run() {
try {
OfflineMapCapabilities offlineMapCapabilities = offlineMapCapabilitiesFuture.get();
if (offlineMapCapabilities.hasErrors()) {
// Handle possible errors with layers
for (java.util.Map.Entry<Layer, OfflineCapability> layerCapability :
offlineMapCapabilities.getLayerCapabilities().entrySet()) {
if (!layerCapability.getValue().isSupportsOffline()) {
showMessage(layerCapability.getKey().getName() + " cannot be taken offline.");
showMessage("Error : " + layerCapability.getValue().getError().getMessage());
}
}
// Handle possible errors with tables
for (java.util.Map.Entry<FeatureTable, OfflineCapability> tableCapability :
offlineMapCapabilities.getTableCapabilities().entrySet()) {
if (!tableCapability.getValue().isSupportsOffline()) {
showMessage(tableCapability.getKey().getTableName() + " cannot be taken offline.");
showMessage("Error : " + tableCapability.getValue().getError().getMessage());
}
}
} else {
// All layers and tables can be taken offline!
showMessage("All layers are good to go!");
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
生成并下载离线地图。
String mExportPath = String.valueOf(getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS)) + File.separator + "New";
showMessage(mExportPath);
// Create and start a job to generate the offline map
final GenerateOfflineMapJob generateOfflineJob =
offlineMapTask.generateOfflineMap(parameters, mExportPath);
// Show that job started
final ProgressBar progressBarOffline = (ProgressBar) findViewById(R.id.progressBarOffline);
progressBarOffline.setVisibility(View.VISIBLE);
generateOfflineJob.start();
generateOfflineJob.addJobDoneListener(new Runnable() {
@Override
public void run() {
// Generate the offline map and download it
GenerateOfflineMapResult result = generateOfflineJob.getResult();
if (!result.hasErrors()) {
showMessage("no error");
mobileMapPackage = result.getMobileMapPackage();
// Job is finished and all content was generated
showMessage("Map " + mobileMapPackage.getItem().getTitle() +
" saved to " + mobileMapPackage.getPath());
// Show offline map in a MapView
mMapView.setMap(result.getOfflineMap());
// Show that job completed
progressBarOffline.setVisibility(View.INVISIBLE);
} else {
showMessage("error");
// Job is finished but some of the layers/tables had errors
if (result.getLayerErrors().size() > 0) {
for (java.util.Map.Entry<Layer, ArcGISRuntimeException> layerError : result.getLayerErrors().entrySet()) {
showMessage("Error occurred when taking " + layerError.getKey().getName() + " offline.");
showMessage("Error : " + layerError.getValue().getMessage());
}
}
if (result.getTableErrors().size() > 0) {
for (java.util.Map.Entry<FeatureTable, ArcGISRuntimeException> tableError : result.getTableErrors().entrySet()) {
showMessage("Error occurred when taking " + tableError.getKey().getTableName() + " offline.");
showMessage("Error : " + tableError.getValue().getMessage());
}
}
// Show that job completed
progressBarOffline.setVisibility(View.INVISIBLE);
}
}
});
(5) 打开并使用离线地图
// Create the mobile map package
final MobileMapPackage mapPackage = new MobileMapPackage(mobileMapPackage.getPath());
// Load the mobile map package asynchronously
mapPackage.loadAsync();
// Add done listener which will invoke when mobile map package has loaded
mapPackage.addDoneLoadingListener(new Runnable() {
@Override
public void run() {
// Check load status and that the mobile map package has maps
if(mapPackage.getLoadStatus() == LoadStatus.LOADED && mapPackage.getMaps().size() > 0){
// Cdd the map from the mobile map package to the MapView
mMapView.setMap(mapPackage.getMaps().get(0));
}else{
// Log an issue if the mobile map package fails to load
showMessage(mapPackage.getLoadError().getMessage());
}
}
});
我的代码中的showMessage()显示Toast。
public void showMessage(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
我担心我的.mmpk的期望值是错误的,或者在某个步骤上出现了错误,因为我仍然没有完全理解整个过程。这是我第一次在Android中使用ArcGIS地图。我找不到太多可以尝试的示例代码,所以非常感谢能够帮忙的人。
谢谢!