bitmapdecode.java

android 例子中的确良ApiDemos。很有代表意义

/*
 * Copyright (C) 2007 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 com.example.android.apis.graphics;

import com.example.android.apis.R;

import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.graphics.drawable.*;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.*;

import java.io.IOException;
import java.io.InputStream;

public class BitmapDecode extends GraphicsActivity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }
    
    private static class SampleView extends View {
        private Bitmap mBitmap;
        private Bitmap mBitmap2;
        private Bitmap mBitmap3;
        private Bitmap mBitmap4;
        private Drawable mDrawable;
        
        private Movie mMovie;
        private long mMovieStart;
        
        public SampleView(Context context) {
            super(context);
            setFocusable(true);
            
            java.io.InputStream is;
            is = context.getResources().openRawResource(R.drawable.beach);
            
            BitmapFactory.Options opts = new BitmapFactory.Options();
            Bitmap bm;
            
            opts.inJustDecodeBounds = true;
            bm = BitmapFactory.decodeStream(is, null, opts);
            
            // now opts.outWidth and opts.outHeight are the dimension of the
            // bitmap, even though bm is null
            
            opts.inJustDecodeBounds = false;    // this will request the bm
            opts.inSampleSize = 4;             // scaled down by 4
            bm = BitmapFactory.decodeStream(is, null, opts);
            
            mBitmap = bm;
            
            // decode an image with transparency
            is = context.getResources().openRawResource(R.drawable.frog);
            mBitmap2 = BitmapFactory.decodeStream(is);
            
            // create a deep copy of it using getPixels() into different configs
            int w = mBitmap2.getWidth();
            int h = mBitmap2.getHeight();
            int[] pixels = new int[w*h];
            mBitmap2.getPixels(pixels, 0, w, 0, 0, w, h);
            mBitmap3 = Bitmap.createBitmap(pixels, 0, w, w, h,
                                           Bitmap.Config.ARGB_8888);
            mBitmap4 = Bitmap.createBitmap(pixels, 0, w, w, h,
                                           Bitmap.Config.ARGB_4444);
            
            mDrawable = context.getResources().getDrawable(R.drawable.button);
            mDrawable.setBounds(150, 20, 300, 100);
            
            is = context.getResources().openRawResource(R.drawable.animated_gif);
            mMovie = Movie.decodeStream(is);
        }
        
        @Override protected void onDraw(Canvas canvas) {
            canvas.drawColor(0xFFCCCCCC);            
            
            Paint p = new Paint();
            p.setAntiAlias(true);
            
            canvas.drawBitmap(mBitmap, 10, 10, null);
            canvas.drawBitmap(mBitmap2, 10, 170, null);
            canvas.drawBitmap(mBitmap3, 110, 170, null);
            canvas.drawBitmap(mBitmap4, 210, 170, null);
            
            mDrawable.draw(canvas);
            
            long now = android.os.SystemClock.uptimeMillis();
            if (mMovieStart == 0) {   // first time
                mMovieStart = now;
            }
            int relTime = (int)((now - mMovieStart) % mMovie.duration());
            mMovie.setTime(relTime);
            mMovie.draw(canvas, getWidth() - mMovie.width(),
                        getHeight() - mMovie.height());
            invalidate();
        }
    }
}