Develop Reference

Vertical top to bottom line gesture detector

I used the https://play.google.com/store/apps/details?id=com.davemac327.gesture.tool&hl=en
gesture tool and noticed that for a line which is top to bottom vertically is not able to detect as i am using the generated gesture file in my code as follows but not able to detect the vertical top to bottom line gesture detection
import java.util.ArrayList;
import android.app.Activity;
import android.gesture.Gesture;
import android.gesture.GestureLibraries;
import android.gesture.GestureLibrary;
import android.gesture.GestureOverlayView;
import android.gesture.Prediction;
import android.gesture.GestureOverlayView.OnGesturePerformedListener;
import android.os.Bundle;
import android.widget.Toast;
public class GesturesActivity extends Activity implements OnGesturePerformedListener {
private GestureLibrary mLibrary;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mLibrary = GestureLibraries.fromRawResource(this, R.raw.gestures);
if (!mLibrary.load()) {
finish();
}
GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures);
gestures.addOnGesturePerformedListener(this);
}
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
ArrayList<Prediction> predictions = mLibrary.recognize(gesture);
String data="";
for (int i = 0; i < predictions.size(); i++) {
data=data+ "=="+predictions.get(i).name;
}
// We want at least one prediction
if (predictions.size() > 0) {
Prediction prediction = predictions.get(0);
// We want at least some confidence in the result
if (prediction.score > 1.0) {
// Show the spell
Toast.makeText(this,data+ " "+ prediction.name, Toast.LENGTH_SHORT).show();
}
}
}
}
please suggest how to perform a vertical top to bottom vertical gesture detection

There was problem with the above code which i solved by introducing
GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures);
gestures.setGestureStrokeAngleThreshold( 90.0f);
As the default value of the angle threashold is 40.0f because of which simple vertical gestures would be skipped so changed it to 90.0f, so finally setting the GestureStrokeAngleThreshold to a value closer to 90.0f works fine

Drawing custom indoor map and links between locations. For each location x,y coordinates are already know to be shown on screen

package com.smallfan.museumexhibition.views;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.view.View;
import android.widget.Toast;
public class CustomDrawableView extends View implements View.OnClickListener {
Drawable drawable;
Paint paint;
String myText;
int x1,y1;
Context context;
public CustomDrawableView(Context context, Drawable mydrawable, int x, int y, String text) {
super(context);
this.myText=text;
this.x1=x;
this.y1=y;
this.paint = new Paint();
this.context=context;
drawable=mydrawable;
drawable.setBounds(x, y, x + drawable.getMinimumWidth(), y + drawable.getMinimumHeight());
setOnClickListener(this);
}
protected void onDraw(Canvas canvas) {
drawable.draw(canvas);
}
#Override
public void onClick(View v)
{
v.setTag(myText);
Toast.makeText(context, "View clicked. "+" tag "+ v.getTag(), Toast.LENGTH_SHORT).show();
}
}
///////////////////////////////////////////////////
package com.smallfan.museumexhibition;
import java.io.InputStream;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.RelativeLayout;
public class MapInActivity extends Fragment
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Log.v("MapInActivity", "onCreate()");
}
DrawView drawView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
Log.v("MapInActivity", "onCreateView()");
View v = LayoutInflater.from(getActivity()).inflate(R.layout.indoormap_layout, null);
RelativeLayout maplayout=(RelativeLayout)v.findViewById(R.id.maplayout);
CustomDrawableView mCustomDrawableView = new CustomDrawableView(getActivity(),getResources().getDrawable(R.drawable.ic_launcher),10,10,"Item 1");
maplayout.addView(mCustomDrawableView);
CustomDrawableView mCustomDrawableView1 = new CustomDrawableView(getActivity(),getResources().getDrawable(R.drawable.ic_launcher),50,50,"Item 2");
maplayout.addView(mCustomDrawableView1);
return v;
}
#Override
public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
Log.v("MapInActivity", "onActivityCreated().");
}
//
}
I have to draw a map like this and also show the overlay on tap of any pin like in Google map. I was able to draw views on canvas along with click listeners, but the click listener action is performed by clicking any where on screen and it's just for the view drawn in last. So if any solution then please let me know. Thanks in advance.

Have you heard of GeoFencing ? The only catch is that it works on the principle of a circle. But that should not be that bad, since you can cover the entrance with 2 circles, 1 that covers the breath of the room and includes the entrance door, and the other circle contained within the bigger circle that only covers the door.
Check out A4, I have drawn 2 circles, sorry for a ugly representation.
If a user enters the smaller circle and the bigger circle than he is still in the room. If he enters the smaller circle and exists it (and is not entering the bigger circle) he has exited the room.
Twisted but will work with minimal coding. Just read up geofencing.
Also note geofencing is now merged with LocationClient API's which consume 8 times lesser battery as compared to LocationManager. So go for it.

Exporting Charts as images in Android

I'm stucked in this for almost a month. I have a perfect chart in my android code using 'afreechart', however, the library does not seem to have support for exporting the chart as an image yet (since it's based on 'jfreechart' and this one does the job).
I tried to get the view of the chart, convert it into canvas and save using the compress functions of the bitmap library, however everytime i try this i get a totally black image as a result. I tried this same method and it works for the other views of my code (simple views, like linearlayout and relativelayout).
After that i tried to create a routine to make a screenshot of the chart activity and close that activity after that. But I couldn't find a way to do that by code, the closest i got was with monkeyrunner.
So i gave up of this idea and tried to look for other libraries, such as 'kichart', 'achartengine', etc, but none of them seem to do the job for, i'm freaking out and i thought that exporting the chart to an image wouldn't be that hard... any ideas?
When i set a background color for the layout, the returned image is a full rectangle with the color of the background, so it's getting the layout, just not the chart.
My Code:
package com.kichart;
import java.io.File;
import java.io.FileOutputStream;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.LinearLayout;
public class Main extends Activity {
LinearLayout ll;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
float[] values = new float[] { 2.0f,1.5f, 2.5f, 1.0f , 3.0f };
String[] verlabels = new String[] { "great", "ok", "bad" };
String[] horlabels = new String[] { "today", "tomorrow", "next week", "next month" };
GraphView graphView = new GraphView(this, values, "GraphViewDemo",horlabels, verlabels, GraphView.BAR);
ll = new LinearLayout(this);
ll.addView(graphView);
Draw2d d = new Draw2d(this);
setContentView(d);
//setContentView(graphView);
}
public class Draw2d extends View {
public Draw2d(Context context) {
super(context);
setDrawingCacheEnabled(true);
}
#Override
protected void onDraw(Canvas c) {
ll.setBackgroundColor(Color.WHITE);
ll.measure(MeasureSpec.getSize(ll.getWidth()), MeasureSpec.getSize(ll.getHeight()));
ll.layout(400, 400, 400, 400);
ll.draw(c);
try {
getDrawingCache().compress(Bitmap.CompressFormat.PNG, 100, new FileOutputStream(new File("/mnt/sdcard/graph2.png")));
} catch (Exception e) {
Log.e("Error--------->", e.toString());
}
super.onDraw(c);
}
}
}

You can get a image bitmap from a view by doing:
Bitmap bitmap;
chart.setDrawingCacheEnabled(true);
bitmap = Bitmap.createBitmap(chart.getDrawingCache());
chart.setDrawingCacheEnabled(false);
if you can't call getDrawingCache on the chart, try to place it inside a layout like RelativeLayout or something like that. and call it on the layout.
After that you can save it as a image..
If the image is still black, you need to make sure the chart is created before getting the bitmap.
Hope this will help you

Android Views Are Not As Tall As Specified

I am using RelativeLayout to position views at precise locations on the screen. This works as expected when using a view that say, draws a rectangle. But when using Android views like EditText, they are drawn shorter than specified by about 8 units. Clicking outside of the drawn EditText (but within the parameters specified by RelativeLayout) will, in fact, hit the EditText.
Here is some code to illustrate what I mean:
package com.DrawDemo;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RelativeLayout;
public class DrawDemo extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
RelativeLayout l = new RelativeLayout(this);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(100,100);
lp.leftMargin = 50;
lp.topMargin = 50;
DemoView demoview = new DemoView(this);
l.addView(demoview, lp);
EditText editText = new EditText(this);
l.addView(editText, lp);
setContentView(l);
}
private class DemoView extends View
{
public DemoView(Context context)
{
super(context);
}
#Override protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.GREEN);
canvas.drawPaint(paint);
}
}
}
If you execute this, you will notice that the EditText is noticeably shorter than the rectangle. I've tried mucking with onMeasure, setMinimumXXX, and just about everything else I can think of. So far, the only thing that works with some level of success is to just add 8 or so pixels to the height (8 seems to work better than trying a percentage of the height).
Next task will be to step into the source but was wondering if somebody has already solved this.
Thanks.

It's just because of the actual EditText background image that's used. Buttons are the same way, for some reason Google decided to draw the 9-patch background images with some extra transparent padding pixels. Really, the only solution, if it's a problem, would be to draw your own 9-patch, or modify the existing Android 9-patch to remove the extra pixels.

Android Drawing

I'm quite new to android, but basically I want to set up a program so that when the user clicks on an imageview, a dot is drawn where they click. I have tried many times but just don't seem to be able to get it to work, and help would be much appreciated.So far I have
package com.smallbore.smallbore;
import android.app.Activity;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.OvalShape;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
public class targetenter extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.targetenter);
ImageView v = (ImageView) findViewById(R.id.imageView1);
v.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
TextView t1 = (TextView) findViewById(R.id.textView2);
TextView t2 = (TextView) findViewById(R.id.textView3);
t1.setText("X: "+arg1.getX());
t2.setText("Y: "+arg1.getY());
int x = (int)arg1.getX();
int y = (int)arg1.getY();
int width = 50;
int height = 50;
ShapeDrawable mDrawable = new ShapeDrawable(new OvalShape());
mDrawable.getPaint().setColor(0xff74AC23);
mDrawable.setBounds(x, y, x + width, y + height);
ImageView v = (ImageView) findViewById(R.id.imageView1)
v.setImageDrawable(mDrawable);
return false;
}
});
};
}

To draw the dots, you'll probably have to use a custom View and override onTouchEvent and onDraw. onTouchEvent will give you the x,y coordinates of the touch event and in onDraw you can draw a circle at this point to the canvas that the framework provides to this method. If you want to clear previous dots, you only need to keep track of the last x,y coordinates. Otherwise, you'll need to keep a running list (ArrayList or something like that).
In your shoes, I'd probably subclass ImageView so that I get the image drawing stuff for free. Call super.onDraw(canvas) inside the overridden onDraw method, and then draw your dots (canvas.drawCircle).

The Android SDK contains a pretty good example : http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/DrawPoints.html
You just need to make SampleView handling click event, and get it displaying the image in SampleView.onDraw method.