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嗨，我做一個小的應用程序，以顯示所有SD卡圖像應該在我的應用程序的縮略圖顯示視圖。我的計劃是像下面如何提高從SDCard加載圖像到我的應用程序的性能？
這裏的問題是，在模擬器加載快速，準確的地方爲手機要花大量的時間。它裝載了一些30MB左右的問題。它是80MB左右，它沒有在我的屏幕上顯示圖像。
注：這是在模擬器而不是設備 和我的圖片路徑完美的工作是「文件：/// SD卡/圖片/」 我的代碼是：
這是我的應用程序啓動器類
public class StartUp extends UiApplication{
public static void main(String[] args) {
StartUp start=new StartUp();
start.enterEventDispatcher();
}
public StartUp() {
pushScreen(new ViewerMainScreen());
}
}
這是我ViewerMainScreen.java
public class ViewerMainScreen extends MainScreen implements FieldChangeListener{
private ObjectListField fileList;
private String currentPath = "file:///";
public VerticalFieldManager vert_manager=null;
private BitmapField before[]=null,next[]=null;
private int size=0;Border b1,b2;
TableLayoutManager colFMgr=null;
private Vector img_data=null;
private int count=0;
public ViewerMainScreen() {
super();
setTitle("Browse to image...");
initGUI();
}
public void initGUI() {
try {
// add(getFileList());
img_data=getAllList("file:///SDCard/images");
b1=BorderFactory.createSimpleBorder(new XYEdges(3,3,3,3),new XYEdges(Color.RED, Color.RED, Color.RED, Color.RED),Border.STYLE_SOLID);
b2=BorderFactory.createSimpleBorder(new XYEdges(0,0,0,0));
size=img_data.size();
before=new BitmapField[size];
next=new BitmapField[size];
vert_manager=new VerticalFieldManager(VERTICAL_SCROLL|VERTICAL_SCROLLBAR){
protected void sublayout(int maxWidth, int maxHeight) {
super.sublayout(Display.getWidth(),Display.getHeight());
setExtent(Display.getWidth(),Display.getHeight());
}
};
colFMgr = new TableLayoutManager(new int[] {
TableLayoutManager.USE_PREFERRED_SIZE,
TableLayoutManager.USE_PREFERRED_SIZE,
TableLayoutManager.USE_PREFERRED_SIZE,
TableLayoutManager.USE_PREFERRED_SIZE,
}, Manager.HORIZONTAL_SCROLL|VERTICAL_SCROLL|VERTICAL_SCROLLBAR);
for(int i= 0;i < size;i++)
{
EncodedImage load_img=EncodedImage.getEncodedImageResource("loading.jpg");
before[i] = new BitmapField(load_img.getBitmap(),Field.FOCUSABLE){
protected boolean navigationClick(int status,int time) {
fieldChangeNotify(0);
return super.navigationClick(status, time);
}
protected void onFocus(int direction)
{
this.setBorder(b1);
invalidate();
}
protected void onUnfocus()
{
this.setBorder(b2);
invalidate();
}
};
colFMgr.add(before[i]);
}
add(colFMgr);
Thread t=new Thread(){
public void run() {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
callImageThread();
}
};
t.start();
} catch (Exception e) {
Dialog.alert(e.getMessage());
}
}
private void callImageThread() {
for(int i=0;i<size;i++)
{
if(count==6){
try {
Thread.sleep(400);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
ImageThread th=new ImageThread(this, "file:///SDCard/images/"+img_data.elementAt(i), i);
th.start();
count++;
}
}
public void ReplaceImage(EncodedImage img,int index)
{
before[index].setBitmap(img.getBitmap());
before[index].setChangeListener(this);
count--;
System.out.println("Thread count: ========================"+Thread.activeCount()+"============================================="+count);
}
public void fieldChanged(Field field, int context) {
for(int i=0;i<size;i++)
{
if(field==before[i])
{
synchronized (UiApplication.getEventLock()) {
EncodedImage img=null;
img=loadFile("file:///SDCard/images/"+img_data.elementAt(i));
int displayWidth = Fixed32.toFP(Display.getWidth()-100);
int imageWidth = Fixed32.toFP(img.getWidth());
int scalingFactorX = Fixed32.div(imageWidth, displayWidth);
int displayHeight = Fixed32.toFP(Display.getHeight()-100);
int imageHeight = Fixed32.toFP(img.getHeight());
int scalingFactorY = Fixed32.div(imageHeight, displayHeight);
EncodedImage scaledImage = img.scaleImage32(scalingFactorX, scalingFactorY);
UiApplication.getUiApplication().pushScreen(new ZoomScreen(scaledImage));
}
}
}
}
public void displayMessage(final String message)
{
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
Dialog.inform(message);
}
});
}
private Vector getAllList(String path){
Vector data=new Vector();
FileConnection fileConnection=null;
try{
fileConnection = (FileConnection) Connector.open(path);
if (fileConnection.isDirectory()) {
Enumeration directoryEnumerator = fileConnection.list();
while (directoryEnumerator.hasMoreElements()) {
data.addElement(directoryEnumerator.nextElement());
}
}
}catch (Exception e) {
System.out.println(e.getMessage());
}
finally
{
if(fileConnection!=null){
try {
fileConnection.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return data;
}
private EncodedImage loadFile(String path) {
FileConnection fileConnection =null;
InputStream inputStream =null;
EncodedImage encodedImage=null;
try {
fileConnection = (FileConnection) Connector.open(path);
if(fileConnection.exists()){
inputStream = fileConnection.openInputStream();
byte[] imageBytes = new byte[(int)fileConnection.fileSize()];
inputStream.read(imageBytes);
encodedImage = EncodedImage.createEncodedImage(imageBytes, 0, imageBytes.length);
if(fileConnection!=null){
try {
fileConnection.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(inputStream!=null){
try {
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
} catch (IOException e) {
Dialog.alert("Insert an SD Card.");
}
return encodedImage;
}
}
這是我ImageThread.java
public class ImageThread extends Thread{
private ViewerMainScreen screen;
private String path;
private int index;
private EncodedImage scaledImage=null;
public ImageThread(ViewerMainScreen screen,String path,int index) {
this.screen=screen;
this.path=path;
this.index=index;
}
public void callMainScreen(EncodedImage eimg,int Rindex) {
screen.ReplaceImage(eimg, Rindex);
}
public void run() {
FileConnection fileConnection =null;
InputStream inputStream =null;
EncodedImage encodedImage=null;
try {
fileConnection = (FileConnection) Connector.open(path);
if(fileConnection.exists()){
inputStream = fileConnection.openInputStream();
byte[] imageBytes = new byte[(int)fileConnection.fileSize()];
inputStream.read(imageBytes);
encodedImage = EncodedImage.createEncodedImage(imageBytes, 0, imageBytes.length);
int displayWidth = Fixed32.toFP(100);
int imageWidth = Fixed32.toFP(encodedImage.getWidth());
int scalingFactorX = Fixed32.div(imageWidth, displayWidth);
int displayHeight = Fixed32.toFP(100);
int imageHeight = Fixed32.toFP(encodedImage.getHeight());
int scalingFactorY = Fixed32.div(imageHeight, displayHeight);
scaledImage = encodedImage.scaleImage32(scalingFactorX, scalingFactorY);
callMainScreen(scaledImage, index);
}
} catch (IOException e) {
Dialog.alert("Insert an SD Card.");
}
finally
{
if(fileConnection!=null){
try {
fileConnection.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(inputStream!=null){
try {
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
請幫助我如何提高我的代碼性能
你爲什麼在ImageDisplayScreen中的paint（）中添加一個新的位圖字段對象？它創建一個新的對象，每次調用油漆 – rfsk2010 2011-12-30 07:44:07
嗨，我不使用那個類，所以現在我刪除這個類。 – 2011-12-30 09:07:48