Android example source code file (ZoomControls.java)

This example Android source code file (ZoomControls.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

alphaanimation, android, annotate, annotations, attributeset, content, layoutinflater, linearlayout, override, ui, view, widget, zoombutton, zoomcontrols

The ZoomControls.java Android example source code

/*
 * Copyright (C) 2008 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.annotation.Widget;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AlphaAnimation;

import com.android.internal.R;


/**
 * The {@code ZoomControls} class displays a simple set of controls used for zooming and
 * provides callbacks to register for events. */
@Widget
public class ZoomControls extends LinearLayout {

    private final ZoomButton mZoomIn;
    private final ZoomButton mZoomOut;
        
    public ZoomControls(Context context) {
        this(context, null);
    }

    public ZoomControls(Context context, AttributeSet attrs) {
        super(context, attrs);
        setFocusable(false);
        
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.zoom_controls, this, // we are the parent
                true);
        
        mZoomIn = (ZoomButton) findViewById(R.id.zoomIn);
        mZoomOut = (ZoomButton) findViewById(R.id.zoomOut);
    }

    public void setOnZoomInClickListener(OnClickListener listener) {
        mZoomIn.setOnClickListener(listener);
    }
    
    public void setOnZoomOutClickListener(OnClickListener listener) {
        mZoomOut.setOnClickListener(listener);
    }
    
    /*
     * Sets how fast you get zoom events when the user holds down the
     * zoom in/out buttons.
     */
    public void setZoomSpeed(long speed) {
        mZoomIn.setZoomSpeed(speed);
        mZoomOut.setZoomSpeed(speed);
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        
        /* Consume all touch events so they don't get dispatched to the view
         * beneath this view.
         */
        return true;
    }
    
    public void show() {
        fade(View.VISIBLE, 0.0f, 1.0f);
    }
    
    public void hide() {
        fade(View.GONE, 1.0f, 0.0f);
    }
    
    private void fade(int visibility, float startAlpha, float endAlpha) {
        AlphaAnimation anim = new AlphaAnimation(startAlpha, endAlpha);
        anim.setDuration(500);
        startAnimation(anim);
        setVisibility(visibility);
    }
    
    public void setIsZoomInEnabled(boolean isEnabled) {
        mZoomIn.setEnabled(isEnabled);
    }
    
    public void setIsZoomOutEnabled(boolean isEnabled) {
        mZoomOut.setEnabled(isEnabled);
    }
    
    @Override
    public boolean hasFocus() {
        return mZoomIn.hasFocus() || mZoomOut.hasFocus();
    }
}