Android example source code file (AbsoluteLayout.java)

This example Android source code file (AbsoluteLayout.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

absolutelayout, android, attributeset, content, deprecated, gone, layoutparams, override, remoteview, string, typedarray, ui, util, utilities, view, viewgroup

The AbsoluteLayout.java Android example source code

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RemoteViews.RemoteView;


/**
 * A layout that lets you specify exact locations (x/y coordinates) of its
 * children. Absolute layouts are less flexible and harder to maintain than
 * other types of layouts without absolute positioning.
 *
 * <p>XML attributes
 
 See {@link
 * android.R.styleable#ViewGroup ViewGroup Attributes}, {@link
 * android.R.styleable#View View Attributes}</p>
 * 
 * @deprecated Use {@link android.widget.FrameLayout}, {@link android.widget.RelativeLayout}
 *             or a custom layout instead.
 */
@Deprecated
@RemoteView
public class AbsoluteLayout extends ViewGroup {
    public AbsoluteLayout(Context context) {
        super(context);
    }

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

    public AbsoluteLayout(Context context, AttributeSet attrs,
            int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int count = getChildCount();

        int maxHeight = 0;
        int maxWidth = 0;

        // Find out how big everyone wants to be
        measureChildren(widthMeasureSpec, heightMeasureSpec);

        // Find rightmost and bottom-most child
        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                int childRight;
                int childBottom;

                AbsoluteLayout.LayoutParams lp
                        = (AbsoluteLayout.LayoutParams) child.getLayoutParams();

                childRight = lp.x + child.getMeasuredWidth();
                childBottom = lp.y + child.getMeasuredHeight();

                maxWidth = Math.max(maxWidth, childRight);
                maxHeight = Math.max(maxHeight, childBottom);
            }
        }

        // Account for padding too
        maxWidth += mPaddingLeft + mPaddingRight;
        maxHeight += mPaddingTop + mPaddingBottom;

        // Check against minimum height and width
        maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
        maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());
        
        setMeasuredDimension(resolveSize(maxWidth, widthMeasureSpec),
                resolveSize(maxHeight, heightMeasureSpec));
    }

    /**
     * Returns a set of layout parameters with a width of
     * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT},
     * a height of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT}
     * and with the coordinates (0, 0).
     */
    @Override
    protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 0, 0);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t,
            int r, int b) {
        int count = getChildCount();

        for (int i = 0; i < count; i++) {
            View child = getChildAt(i);
            if (child.getVisibility() != GONE) {

                AbsoluteLayout.LayoutParams lp =
                        (AbsoluteLayout.LayoutParams) child.getLayoutParams();

                int childLeft = mPaddingLeft + lp.x;
                int childTop = mPaddingTop + lp.y;
                child.layout(childLeft, childTop,
                        childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());

            }
        }
    }

    @Override
    public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new AbsoluteLayout.LayoutParams(getContext(), attrs);
    }

    // Override to allow type-checking of LayoutParams. 
    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof AbsoluteLayout.LayoutParams;
    }

    @Override
    protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
        return new LayoutParams(p);
    }

    /**
     * Per-child layout information associated with AbsoluteLayout.
     * See
     * {@link android.R.styleable#AbsoluteLayout_Layout Absolute Layout Attributes}
     * for a list of all child view attributes that this class supports.
     */
    public static class LayoutParams extends ViewGroup.LayoutParams {
        /**
         * The horizontal, or X, location of the child within the view group.
         */
        public int x;
        /**
         * The vertical, or Y, location of the child within the view group.
         */
        public int y;

        /**
         * Creates a new set of layout parameters with the specified width,
         * height and location.
         *
         * @param width the width, either {@link #MATCH_PARENT},
                  {@link #WRAP_CONTENT} or a fixed size in pixels
         * @param height the height, either {@link #MATCH_PARENT},
                  {@link #WRAP_CONTENT} or a fixed size in pixels
         * @param x the X location of the child
         * @param y the Y location of the child
         */
        public LayoutParams(int width, int height, int x, int y) {
            super(width, height);
            this.x = x;
            this.y = y;
        }

        /**
         * Creates a new set of layout parameters. The values are extracted from
         * the supplied attributes set and context. The XML attributes mapped
         * to this set of layout parameters are:
         *
         * <ul>
         *   <li>layout_x: the X location of the child
         *   <li>layout_y: the Y location of the child
         *   <li>All the XML attributes from
         *   {@link android.view.ViewGroup.LayoutParams}</li>
         * </ul>
         *
         * @param c the application environment
         * @param attrs the set of attributes fom which to extract the layout
         *              parameters values
         */
        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
            TypedArray a = c.obtainStyledAttributes(attrs,
                    com.android.internal.R.styleable.AbsoluteLayout_Layout);
            x = a.getDimensionPixelOffset(
                    com.android.internal.R.styleable.AbsoluteLayout_Layout_layout_x, 0);
            y = a.getDimensionPixelOffset(
                    com.android.internal.R.styleable.AbsoluteLayout_Layout_layout_y, 0);
            a.recycle();
        }

        /**
         * {@inheritDoc}
         */
        public LayoutParams(ViewGroup.LayoutParams source) {
            super(source);
        }

        @Override
        public String debug(String output) {
            return output + "Absolute.LayoutParams={width="
                    + sizeToString(width) + ", height=" + sizeToString(height)
                    + " x=" + x + " y=" + y + "}";
        }
    }
}