[android-beginners] Re: My First Custom View
Bump...anyone?
On Jun 15, 7:42 pm, Dave Smith dasmith1...@gmail.com wrote:
Hi all -
I'm trying to get a custom view example running out of the
Professional Android Application Development book (the
CompassView). I have checked over my code numerous times, and still
the same problem occurs...whenever I run the application I only see a
black screen and the view never pops up.
I have stepped through the debugger a few times and I have two
theories:
1. I have a problem with onMeasure()...my code is currently calling
setMeasuredDimension with 0,0
2. The view might be invisible...I read back the value of
CompassView.isShown() and it read false
Here is the measure code that is being used:
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// The compass is a circle that fills as much screen as
possible.
// Set the measured dimensions to the shortest screen
boundary.
int measuredWidth = measure(widthMeasureSpec);
int measuredHeight = measure(heightMeasureSpec);
int d = Math.min(measuredWidth, measuredHeight);
//setMeasuredDimension must be called by onMeasure
setMeasuredDimension(d, d);
}
private int measure(int measureSpec){
int result = 0;
//Decode the spec value
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(specMode);
if(specMode == MeasureSpec.UNSPECIFIED){
//Return a default value
result = 200;
} else {
//Return full bounds since we are filling available
space
result = specSize;
}
measure() is returning MeasureSpec.EXACTLY for mode and 0 for size
from both width and height. How is that possible? I can attach more
code if necessary, because my other problem is that onDraw() never
gets called...but I thought that might have something to do with
having no size.
If it matters, I ran this under Android 1.1 and 1.5 to be sure I
didn't miss something in a version update.
Thanks in advance!
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[android-beginners] My First Custom View
Hi all -
I'm trying to get a custom view example running out of the
Professional Android Application Development book (the
CompassView). I have checked over my code numerous times, and still
the same problem occurs...whenever I run the application I only see a
black screen and the view never pops up.
I have stepped through the debugger a few times and I have two
theories:
1. I have a problem with onMeasure()...my code is currently calling
setMeasuredDimension with 0,0
2. The view might be invisible...I read back the value of
CompassView.isShown() and it read false
Here is the measure code that is being used:
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// The compass is a circle that fills as much screen as
possible.
// Set the measured dimensions to the shortest screen boundary.
int measuredWidth = measure(widthMeasureSpec);
int measuredHeight = measure(heightMeasureSpec);
int d = Math.min(measuredWidth, measuredHeight);
//setMeasuredDimension must be called by onMeasure
setMeasuredDimension(d, d);
}
private int measure(int measureSpec){
int result = 0;
//Decode the spec value
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(specMode);
if(specMode == MeasureSpec.UNSPECIFIED){
//Return a default value
result = 200;
} else {
//Return full bounds since we are filling available
space
result = specSize;
}
measure() is returning MeasureSpec.EXACTLY for mode and 0 for size
from both width and height. How is that possible? I can attach more
code if necessary, because my other problem is that onDraw() never
gets called...but I thought that might have something to do with
having no size.
If it matters, I ran this under Android 1.1 and 1.5 to be sure I
didn't miss something in a version update.
Thanks in advance!
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[android-beginners] My First Custom View Totally Busted
Hi all -
I'm trying to get up to speed with custom views, and I took most of
this code from examples, but I cannot get it to do anything. When I
run the code below in the emulator I just get a blank screen, and when
I set debug breakpoints it shows that onDraw() never gets called!
It's got to be something dumb and simple, but I don't see it. I'm
just trying to get a circle painted for starters. I even tried adding
an mv.invalidate() call to the onCreate() method to try and get it
to redraw but nothing changed. Help!
Thanks in advance!
[main.xml]
?xml version=1.0 encoding=utf-8?
LinearLayout xmlns:android=http://schemas.android.com/apk/res/
android
android:orientation=vertical
android:layout_width=fill_parent
android:layout_height=fill_parent
com.examples.customview.myView
android:id=@+id/myView
android:layout_width=fill_parent
android:layout_height=fill_parent/
/LinearLayout
[/main.xml]
[myActivity.java]
package com.examples.customview;
import android.app.Activity;
import android.os.Bundle;
public class Compass extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myView mv = (myView)this.findViewById(R.id.myView);
}
}
[/myActivity.java]
[myView.java]
package com.examples.customview;
import android.content.Context;
import android.graphics.*;
import android.view.*;
import android.util.AttributeSet;
import android.content.res.Resources;
public class myView extends View {
[...private members...]
public myView(Context context){
super(context);
initView();
}
public myView(Context context, AttributeSet attrs){
super(context, attrs);
initView();
}
public myView(Context context, AttributeSet attrs, int defaultStyle){
super(context, attrs, defaultStyle);
initView();
}
protected void initView(){
setFocusable(true);
circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
circlePaint.setColor(R.color.background_color);
circlePaint.setStrokeWidth(1);
circlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// The compass is a circle that fills as much screen as
possible.
// Set the measured dimensions to the shortest screen boundary.
int measuredWidth = measure(widthMeasureSpec);
int measuredHeight = measure(heightMeasureSpec);
int d = Math.min(measuredWidth, measuredHeight);
//setMeasuredDimension must be called by onMeasure
setMeasuredDimension(d, d);
}
private int measure(int measureSpec){
int result = 0;
//Decode the spec value
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(specMode);
if(specMode == MeasureSpec.UNSPECIFIED){
//Return a default value
result = 200;
} else {
//Return full bounds since we are filling available
space
result = specSize;
}
return result;
}
@Override
protected void onDraw(Canvas canvas){
//Find the center point
int px = getMeasuredWidth() / 2;
int py = getMeasuredHeight() / 2;
int radius = Math.min(px, py);
//Draw the background
canvas.drawCircle(px, py, radius, circlePaint);
}
}
[/myView.java]
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