Custom zoom buttons

emux

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Mar 23, 2014, 9:06:39 AM3/23/14

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(Continuing the conversation from here)

I remember mapsforge 0.3.X having support for min / max zoom levels, but with its default zoom controls.
Its MapZoomControls class has setZoomLevelMin / setZoomLevelMax methods.

For different drawable at each button state (normal, disabled, pressed) you need
the StateListDrawable class. Take a look at the guide here.

But (if possible) it's really advisable to move to rescue branch.
A lot of these issues have been reworked/resolved there
and you don't need to invent the wheel again.

Emux
Cruiser - Cruiser Beta
Atlas - Atlas Beta

Daniele Germano

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Mar 24, 2014, 8:33:55 AM3/24/14

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Thanks for your patience.

I use the StateListDrwawable but it has no effect for the maxzoom level.

this is my selector for zoom in

<?xml version="1.0" encoding="utf-8"?>

</selector>

And this is the Activity

private static final File MAP_FILE = new File(Environment.getExternalStorageDirectory().getPath() + "/Bluetooth/", "isle.map");

private static final Byte MIN_ZOOM_LEVEL = new Byte("12");

private static final Byte MAX_ZOOM_LEVEL = new Byte("22");

private byte zoomLevelMax;

private byte zoomLevelMin;

private MyLocationOverlay myLocationOverlay;

MapView mapView;

private void configureMapView() {

FileOpenResult fileOpenResult = this.mapView.setMapFile(MAP_FILE);

if (!fileOpenResult.isSuccess()) {

Toast.makeText(this, fileOpenResult.getErrorMessage(), Toast.LENGTH_LONG).show();

}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

this.mapView = (MapView) findViewById(R.id.mapView);

this.mapView.setBuiltInZoomControls(false);

this.mapView.setClickable(true);

MapFileInfo mapFileInfo = this.mapView.getMapDatabase().getMapFileInfo();

this.mapView.getMapViewPosition().setCenter(mapFileInfo.boundingBox.getCenterPoint());

this.mapView.setFocusable(true);

zoomLevelMin = MIN_ZOOM_LEVEL;

zoomLevelMax = MAX_ZOOM_LEVEL;

this.mapView.getMapZoomControls().setZoomLevelMin(zoomLevelMin);

this.mapView.getMapZoomControls().setZoomLevelMax(zoomLevelMax);

MapScaleBar mapScaleBar = this.mapView.getMapScaleBar();

mapScaleBar.setShowMapScaleBar(true);

ImageButton zoomIn = (ImageButton) findViewById(R.id.zoomIn);

zoomIn.setBackgroundResource(R.drawable.action_click_zoom_in);

zoomIn.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

mapView.getMapViewPosition().zoomIn();

}

});

ImageButton zoomOut = (ImageButton) findViewById(R.id.zoomOut);

zoomOut.setBackgroundResource(R.drawable.action_click_zoom_out);

zoomOut.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

mapView.getMapViewPosition().zoomOut();

}

});

configureMapView();

}

Seems that the selector can not see when the maxzoom is reached and insert the icon max_zoom_reached

emux

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Mar 24, 2014, 9:34:09 AM3/24/14

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You have to set at the zoom buttons their state, depending on current zoom level.

For example check for zoom level changes and when zoom level
reaches min / max zoom level then call zoomButton.setEnabled(false).

If you follow the steps through MapZoomControls.onZoomLevelChange
you'll see what happens at ZoomControls src code.

--

Daniele Germano

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Mar 24, 2014, 11:55:33 AM3/24/14

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Hi
The onZoomLevelChange report this

void onZoomLevelChange(int newZoomLevel) {

boolean zoomInEnabled = newZoomLevel < this.zoomLevelMax;

boolean zoomOutEnabled = newZoomLevel > this.zoomLevelMin;

this.zoomControls.setIsZoomInEnabled(zoomInEnabled);

this.zoomControls.setIsZoomOutEnabled(zoomOutEnabled);

}

The problem is that i don't know ho to implement a similar function to my activity.

The onZoomLevelChange says that unti the current zoom in less than the max zoom, to set the zoom in enable.

But how can implement a similar function as you suggest, means, check the current zoom level and set the zoomButton.setEnabled(false) ?

I know that if i just put the zoomButton.setEnabled(false). inside the zoom max click method, it return false, show different icon and do not allow to zoom, but i can't understand how to first check the actual zoom level and start zoomButton.setEnabled(false) when max zoom is reached.

emux

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Mar 24, 2014, 12:18:13 PM3/24/14

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At rescue branch you can use observer functionality.

At 0.3.X versions you can subclass MapView and override dispatchDraw like:

int oldZoomLevel = -1;

@Override
protected void dispatchDraw(Canvas canvas) {
    super.dispatchDraw(canvas);

    if (getMapViewPosition().getZoomLevel() != oldZoomLevel) {
        // Update zoom controls here
        oldZoomLevel = getMapViewPosition().getZoomLevel();
    }
}

Daniele Germano

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Mar 24, 2014, 2:06:28 PM3/24/14

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I have try, but it throw a nullPointerException

03-24 18:57:33.384: E/AndroidRuntime(22148): FATAL EXCEPTION: main

03-24 18:57:33.384: E/AndroidRuntime(22148): java.lang.NullPointerException

03-24 18:57:33.384: E/AndroidRuntime(22148): at org.mapsforge.android.maps.MapView.dispatchDraw(MapView.java:610)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.View.draw(View.java:14544)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.View.getDisplayList(View.java:13476)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.View.getDisplayList(View.java:13520)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.View.draw(View.java:14254)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.ViewGroup.drawChild(ViewGroup.java:3155)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3024)

03-24 18:57:33.384: E/AndroidRuntime(22148): at android.view.View.getDisplayList(View.java:13474)