如何在不发送SavedInstanceState的情况下开始一个新的Android活动？

Question

我是一个新的Android开发者，我有一个问题，当我开始一个新的活动，提供一个项目列表的细节。

我的第一个活动是列出智能手机上安装的所有应用程序。当我单击此列表的一个项目时，第二个活动开始显示该项目的详细信息。

我的PInfo对象是包含所有应用程序信息（版本、名称、位图）的对象。

public class PInfo implements Serializable{

private static final long serialVersionUID = 1L;
private String appname = "";
private String pname = "";
private String versionName = "";
private int versionCode = 0;    
private Bitmap icon ;

private static ByteBuffer dst;
private static byte[] bytesar;

public String getAppname() {
    return appname;
}
public void setAppname(String appname) {
    this.appname = appname;
}
public String getPname() {
    return pname;
}
public void setPname(String pname) {
    this.pname = pname;
}
public String getVersionName() {
    return versionName;
}
public void setVersionName(String versionName) {
    this.versionName = versionName;
}
public int getVersionCode() {
    return versionCode;
}
public void setVersionCode(int versionCode) {
    this.versionCode = versionCode;
}
public Bitmap getIcon() {
    return icon;
}
public void setIcon(Bitmap icon) {
    this.icon = icon;
}
private void writeObject(ObjectOutputStream out) throws IOException{

    out.writeObject(appname);
    out.writeObject(pname);
    out.writeObject(versionName);
    out.writeInt(versionCode);


    out.writeInt(icon.getRowBytes());
    out.writeInt(icon.getHeight());
    out.writeInt(icon.getWidth());

    int bmSize = icon.getRowBytes() * icon.getHeight();
    if(dst==null || bmSize > dst.capacity())
        dst= ByteBuffer.allocate(bmSize);

    out.writeInt(dst.capacity());

    dst.position(0);

    icon.copyPixelsToBuffer(dst);
    if(bytesar==null || bmSize > bytesar.length)
        bytesar=new byte[bmSize];

    dst.position(0);
    dst.get(bytesar);


    out.write(bytesar, 0, bytesar.length);

}

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException{

    appname=(String) in.readObject();

    pname=(String) in.readObject();
    versionName=(String) in.readObject();
    versionCode= in.readInt();


    int nbRowBytes=in.readInt();
    int height=in.readInt();
    int width=in.readInt();

    int bmSize=in.readInt();



    if(bytesar==null || bmSize > bytesar.length)
        bytesar= new byte[bmSize];


    int offset=0;

    while(in.available()>0){
        offset=offset + in.read(bytesar, offset, in.available());
    }


    if(dst==null || bmSize > dst.capacity())
        dst= ByteBuffer.allocate(bmSize);
    dst.position(0);
    dst.put(bytesar);
    dst.position(0);
    icon=Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
    icon.copyPixelsFromBuffer(dst);
    //in.close();
}

我的列表活动：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_application_list);
    
    if (savedInstanceState != null) {
        apps = (ArrayList<PInfo>) savedInstanceState.getSerializable("apps");
    } else {
        apps = new ArrayList<PInfo>();
        apps = getInstalledApps(false);
    }
    appAdapter = new AppAdapter(apps);
    setListAdapter(appAdapter);

}
@Override
protected void onListItemClick(ListView l, View v, int position, long index) {

    AppAdapter appAdapter = new AppAdapter(apps);
    PInfo app = appAdapter.getItem(position);
    Intent intent = new Intent(ApplicationListActivity.this,ApplicationDetailActivity.class);
    //intent.putExtra("app", app);
    intent.putExtra("app_index", index);

    startActivity(intent);
}


private ArrayList<PInfo> getInstalledApps(boolean getSysPackages) {
    ArrayList<PInfo> res = new ArrayList<PInfo>();        
    List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);
    for(int i=0;i<packs.size();i++) {
        PackageInfo p = packs.get(i);
        if ((!getSysPackages) && (p.versionName == null)) {
            continue ;
        }
        PInfo newInfo = new PInfo();
        newInfo.setAppname(p.applicationInfo.loadLabel(getPackageManager()).toString());
        newInfo.setPname(p.packageName);
        newInfo.setVersionName(p.versionName);
        newInfo.setVersionCode(p.versionCode);
        Drawable d = p.applicationInfo.loadIcon(getPackageManager());                
        Bitmap bitmap = ((BitmapDrawable)d).getBitmap();
        newInfo.setIcon(bitmap);
        res.add(newInfo);
    }
    return res; 
}
@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putSerializable("apps", apps);
    super.onSaveInstanceState(outState);
}

我的详细信息活动：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_application_detail);
        
    //PInfo p = (PInfo)getIntent().getExtras().getSerializable("app");
    PackageInfo p = getPackageManager().getInstalledPackages(0).get((int)getIntent().getExtras().getLong("app_index"));
    
    appName = (TextView) findViewById(R.id.appName);
    versionName = (TextView) findViewById(R.id.versionName);
    detailIcon = (ImageView) findViewById(R.id.detailIcon);
    
    appName.setText(p.applicationInfo.loadLabel(getPackageManager()).toString());
    versionName.setText(p.versionName);
    detailIcon.setImageDrawable(p.applicationInfo.loadIcon(getPackageManager()));
    
    
}

10-31 15:06:53.065:D/DalvikVM(3406):WAIT_FOR_CONCURRENT_GC阻塞20ms

10-31 15:06:53.100:D/DalvikVM(3406):GC_CONCURRENT释放1013K,18%释放46177K/55751K,暂停12ms+3ms,总计33ms

10-31 15:06:53.100:D/DalvikVM(3406):WAIT_FOR_CONCURRENT_GC阻塞21ms

10-31 15:06:53.115:D/DalvikVM(3406):GC_FOR_ALLOC释放0K，18%释放46177K/55751K，暂停13ms，总计13ms

10-31 15:06:53.115:I/dalvikvm-heap（3406）：将堆（frag大小写）增长到47.644MB，用于2105798字节分配

10-31 15:06:53.145:D/DalvikVM(3406):GC_CONCURRENT释放1027K，16%释放47206K/55751K，暂停12ms+3ms，总计30ms

10-31 15:06:53.145:D/DalvikVM(3406):WAIT_FOR_CONCURRENT_GC阻塞16ms

10-31 15:06:53.160:D/DalvikVM(3406):GC_FOR_ALLOC释放0K，16%释放47206K/55751K，暂停15ms，总计15ms

10-31 15:06:53.165:I/dalvikvm-heap（3406）：将堆（frag大小写）增长到50.659MB，用于4213190字节分配

10-31 15:06:53.195:D/DalvikVM(3406):GC_CONCURRENT释放6664K，20%释放44656K/55751K，暂停12ms+3ms，总计32ms

10-31 15:06:53.195:D/DalvikVM(3406):WAIT_FOR_CONCURRENT_GC阻塞19ms

1. 我想知道启动详细信息活动时发生了什么？
2. 此循环是否将来自所有应用程序的所有位图序列化到ByteBuffer中？
3. 不启动此循环，如何启动详细信息活动？

我希望我已经足够清楚了，抱歉，可能的拼写错误。

Answer 1

最后，是我的readObject和writeObject不适合位图的序列化。我找到了另一种方法，但存在一些性能问题（返回列表需要4或5秒）：在Java中序列化和反序列化android.graphics.bitmap