Question

I need to create a circle that rotates and contains data for my application. Should I create a customized object for my application or should I make a in-application widget?

While on the topic, how do you refer to a widget within an application instead of a stand alone widget for the android desktop?

Answer 1

This is a rotatable LinearLayout that you can put everything in it and you can rotate it by degree if you customize it. use rotate() method to rotate it and…

enjoy! 😉

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.LinearLayout;

public class RotateLinearLayout extends LinearLayout {

    private Matrix mForward = new Matrix();
    private Matrix mReverse = new Matrix();
    private float[] mTemp = new float[2];
    private float degree = 0;

    public RotateLinearLayout(Context context) {
        super(context);
    }

    public RotateLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {

        try {
            if (degree == 0) {
                super.dispatchDraw(canvas);
                return;
            }
            canvas.rotate(degree, getWidth() / 2, getHeight() / 2);

            mForward = canvas.getMatrix();
            mForward.invert(mReverse);
            canvas.save();
            canvas.setMatrix(mForward); // This is the matrix we need to use for
                                        // proper positioning of touch events

            super.dispatchDraw(canvas);
            canvas.restore();
            invalidate();
        } catch (Exception e) {

        }

    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        if (degree == 0) {
            return super.dispatchTouchEvent(event);
        }
        // final float[] temp = mTemp;
        // temp[0] = event.getX();
        // temp[1] = event.getY();
        // mReverse.mapPoints(temp);
        // event.setLocation(temp[0], temp[1]);
        event.setLocation(getWidth() - event.getX(), getHeight() - event.getY());
        return super.dispatchTouchEvent(event);
    }

    public void rotate() {
        if (degree == 0) {
            degree = 180;
        } else {
            degree = 0;
        }
    }

}

Update:

add this code to your xml layout and put your Views like ImageView or another LinearLayout in it :

<org.mabna.order.ui.RotateLinearLayout  android:id="@+id/llParent"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_gravity="center"
    android:gravity="center"
    android:orientation="horizontal" >



<ImageView
                        android:id="@+id/myImage"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_margin="5dip"
                        android:src="@drawable/main01" />

</org.mabna.order.ui.RotateLinearLayout>

in onCreate() method:

llParent = (RotateLinearLayout) this.findViewById(R.id.llParent);

in onClickListener of a button:

protected void btnRotate_onClick() {
        llParent.rotate();
    }

Update2:

You can use an animation for rotation before real rotation (llParent.rotate();). it needs an animation layout like rotate_dialog.xml:

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

<rotate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="1000" android:fromDegrees="-180" android:toDegrees="0"
    android:pivotX="50%" android:pivotY="50%" android:fillAfter="true" />

and in your code:

protected void btnRotate_onClick() {
        // rotate 
        Animation rotateAnimation = AnimationUtils.loadAnimation(this,
                R.anim.rotate_dialog);
        llParent.startAnimation(rotateAnimation);
        llParent.rotate();
    }