英文:
Android Java Added an ArrayList now program is running very slow
问题
我添加了一个 Arraylist，导致代码运行变慢。我的原始代码大致如下：
//绘制图块
for (int i = 0; i < bitmaps.length; i++) {
for (int a = 0; a < bitmaps[i].length; a++) {
if (bitmaps[i][a] != null) {
//确保图块只在屏幕上绘制
if (tileRect[i][a].left > RunMovement.getCurrentView() - 25 && tileRect[i][a].left < RunMovement.getCurrentView() + screenWidth + 25) {
mCanvas.drawBitmap(bitmaps[i][a], null, tileRect[i][a], null);
}
}
}
}
我需要添加一个 Arraylist 来存储不同的层级，所以我将其改为如下：
//对于新的数组层级
for (int b = 0; b < levelTileList.size(); b++) {
//绘制图块
for (int i = 0; i < levelTileList.get(b).length; i++) {
for (int a = 0; a < levelTileList.get(b)[i].length; a++) {
if (levelTileList.get(b)[i][a] != null) {
//确保图块只在屏幕上绘制
if (levelTileListRec.get(b)[i][a].left > RunMovement.getCurrentView() - 25 && levelTileListRec.get(b)[i][a].left < RunMovement.getCurrentView() + screenWidth + 25) {
mCanvas.drawBitmap(levelTileList.get(b)[i][a], null, levelTileListRec.get(b)[i][a], null);
}
}
}
}
}
代码可以运行，但我的程序明显变得运行缓慢。有人能告诉我为什么吗？如果有方法可以修复吗？
英文:
I added a Arraylist and is slowed down my code.
My original code looked something like this:
//to draw the tiles
for (int i = 0; i < bitmaps.length; i++) {
for (int a = 0; a < bitmaps[i].length; a++) {
if (bitmaps[i][a] != null) {
//to make sure tiles only get drawn on the screen
if(tileRect[i][a].left > RunMovement.getCurrentView() -25 && tileRect[i][a].left < RunMovement.getCurrentView() + screenWidth + 25) {
mCanvas.drawBitmap(bitmaps[i][a], null, tileRect[i][a], null);
}
}
}
}
I needed to add a Arraylist to store different levels, so I changed it to this
//for the new array levels
for (int b = 0; b < levelTileList.size(); b++) {
//to draw the tiles
for (int i = 0; i < levelTileList.get(b).length; i++) {
for (int a = 0; a < levelTileList.get(b)[i].length; a++) {//hope this works
if (levelTileList.get(b)[i][a] != null) {
//to make sure tiles only get drawn on the screen
if (levelTileListRec.get(b)[i][a].left > RunMovement.getCurrentView() - 25 && levelTileListRec.get(b)[i][a].left < RunMovement.getCurrentView() + screenWidth + 25) {
//mCanvas.drawBitmap(bitmaps[i][a], null, tileRect[i][a], null);
mCanvas.drawBitmap(levelTileList.get(b)[i][a], null, levelTileListRec.get(b)[i][a], null);
}
}
}
}
}
The code works but my program slowed down drastically.
Can someone please tell me why, and if there's a way to fix it.
答案1
得分: 0
列表，总的来说，是数据结构，初始化时间和访问时间都比数组慢得多，这仅仅是因为它们的实现方式。
英文:
Lists, in general, are data structures that are way slower than arrays, terms of initializing time and accessing time, just because the way they are implemented.
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