java - 是否可以像在 android 中一样为我的应用程序的活动创建一个最近的屏幕
问题描述
我正在尝试制作一个Activity将在我的应用程序中而不是在 android 设备中保存所有最近的屏幕。它的想法是像在 android 中一样创建最近视图。我暂时不知道如何做到这一点。我在android的官方网站上搜索过，但没有得到我想要的。我有一些活动已经宣布WebView，我想把title, url and the view它Url保存下来以显示在VisualHistory. 我能做的设计我已经实现了，但我不知道如何显示最近的屏幕或视图。背景的颜色应该基于 url。如果有人不明白某些事情，请告诉我。
您可以在下面找到一张照片，该照片将显示我正在尝试做的事情，我从另一个应用程序中复制了这张照片。
我已经计划了这些步骤来实现这一目标。在Pojo.classand in dbit 中没有定义imagewhich 将在 中显示，cardview因为我不知道如何实现。我希望目前蓝色的背景取决于 url 颜色。有什么方法可以获取网址的颜色吗？
创建一个 POJO.class
创建一个将保存此数据的数据库
创建一个适配器
创建一个片段
我在这里有一个日志，它向我显示了这些项目。
[VisualHistoryItem{id=109, title='维基百科，免费百科全书', url=' https://en.m.wikipedia.org/w/index.php?title=Main_Page '}, VisualHistoryItem{id=112, title='', url=' https://mail.google.com/ '}, VisualHistoryItem{id=113, title='Gmail – kostenloser Speicherplatz und E-Mails von Google', url=' https://www .google.com/intl/de/gmail/about/# '}]
这保存了一个视觉历史项目。
mVisualHistory.setUrl(url);
mVisualHistory.setTitle(view.getTitle());
Bitmap topass= getSnapshoot.takeScreenShot(BookmarkActivity.this);
try {
String filename = mVisualHistory.getId()+".png";
FileOutputStream stream = BookmarkActivity.this.openFileOutput(filename, Context.MODE_PRIVATE);
topass.compress(Bitmap.CompressFormat.PNG, 100, stream);
stream.close();
topass.recycle();
} catch (Exception e) {
e.printStackTrace();
}
mVisualRepository.insertNoteTask(mVisualHistory);
我创建了一个Activity代码如下。
public class ActivityTabs extends AppCompatActivity implements View.OnClickListener {
private PopupMenu mPopupMenu;
private FrameLayout settings;
private FrameLayout frameLayout;
private LinearLayout linearLayout;
private ImageView incognito;
private TextView textOfHistory;
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabs);
findViewById(R.id.vgGoMain).setOnClickListener(this);
findViewById(R.id.vgAdd).setOnClickListener(this);
settings = findViewById(R.id.vgSettingsHis);
linearLayout = findViewById(R.id.layoutEmptyVisHistory);
settings.setOnClickListener(this);
textOfHistory = findViewById(R.id.tvEmptyHistory);
FragmentVisualHistoryVertical newFragment = new FragmentVisualHistoryVertical();
getSupportFragmentManager().beginTransaction().add(R.id.frameLayoutVisHistory, newFragment).commit();
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.frameLayoutVisHistory, newFragment)
.commit();
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.vgGoMain:
finish();
return;
case R.id.vgAdd:
Intent intent = new Intent(this, ActivitySearchEngine.class);
startActivity(intent);
finish();
return;
case R.id.vgSettingsHis:
showMenuSettings();
return;
default:
break;
}
}
public void showMenuSettings() {
mPopupMenu = new PopupMenu(this, settings);
final MenuInflater menuInflater = mPopupMenu.getMenuInflater();
menuInflater.inflate(R.menu.history_settings, mPopupMenu.getMenu());
mPopupMenu.show();
}
}
这就是XML为此Activity。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@color/historyEmptyBack"
android:gravity="center_horizontal"
android:orientation="vertical">
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout
android:id="@+id/frameLayoutVisHistory"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingBottom="@dimen/bottomPanelHeight"></FrameLayout>
<LinearLayout
android:id="@+id/layoutEmptyVisHistory"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:visibility="gone">
<TextView
android:id="@+id/tvEmptyHistoryTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="@dimen/common_24dp"
android:gravity="center_horizontal"
android:lineSpacingExtra="3.0sp"
android:text="@string/VHVEmptyTite"
android:textColor="@color/historyEmptyTitle"
android:textSize="22.0sp" />
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="48.0dip"
android:layout_weight="1.0">
<LinearLayout
android:id="@+id/horizontalEmpty"
style="@style/LayoutEmptySmile"
android:layout_width="@dimen/visual_history_element_width"
android:layout_height="@dimen/visual_history_element_height"
android:orientation="vertical">
<ImageView
style="@style/EmptyHistorySmile"
android:src="@drawable/vh_smile_gray" />
<TextView
style="@style/EmptyHistoryText"
android:layout_marginTop="@dimen/common_16dp"
android:gravity="center_horizontal"
android:paddingLeft="@dimen/common_16dp"
android:paddingRight="@dimen/common_16dp"
android:text="@string/VHVEmptyDesc" />
</LinearLayout>
<LinearLayout
android:id="@+id/verticalEmpty"
style="@style/LayoutEmptySmile"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="@dimen/common_24dp"
android:layout_marginRight="@dimen/common_24dp"
android:orientation="horizontal"
android:paddingLeft="@dimen/common_16dp"
android:paddingTop="@dimen/common_16dp"
android:paddingRight="@dimen/common_16dp"
android:paddingBottom="@dimen/common_16dp">
<ImageView
style="@style/EmptyHistorySmile"
android:src="@drawable/vh_smile_gray" />
<TextView
style="@style/EmptyHistoryText"
android:layout_width="wrap_content"
android:gravity="left"
android:paddingLeft="@dimen/common_16dp"
android:text="@string/VHVEmptyDesc" />
</LinearLayout>
<LinearLayout
android:id="@+id/layoutIncognito"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/bottomPanelHeight"
android:visibility="visible">
<LinearLayout
android:id="@+id/layoutEmptyDesc"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="@dimen/common_16dp"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="@+id/ivEmptyHistory"
android:layout_width="@dimen/history_private"
android:layout_height="@dimen/history_private"
android:src="@drawable/incognito_icon_history" />
<TextView
android:id="@+id/tvEmptyHistory"
style="@style/EmptyHistoryText"
android:layout_marginTop="@dimen/common_16dp"
android:gravity="center_horizontal"
android:paddingLeft="@dimen/common_16dp"
android:paddingRight="@dimen/common_16dp"
android:text="@string/SVSearchPrivateMode"
android:textColor="@color/historyTextColor"
android:textSize="@dimen/common_18sp" />
</LinearLayout>
</LinearLayout>
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="@color/historyEmptyBack"
android:gravity="bottom"
android:orientation="vertical"
android:paddingLeft="2.0dip"
android:paddingRight="2.0dip">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="horizontal">
<LinearLayout style="@style/VisHistoryMenuSideLayout">
<FrameLayout
android:id="@+id/vgGoMain"
style="@style/VisHistoryFrLayoutMenu"
android:paddingRight="14.0dip">
<TextView
style="@style/VisHistoryTvMenu"
android:text="@string/VHVHomeBarButtonItemTitle" />
</FrameLayout>
<View style="@style/VisHistoryEmptyView" />
</LinearLayout>
<FrameLayout
android:id="@+id/vgAdd"
style="@style/VisHistoryFrLayoutMenu">
<ImageView
style="@style/VisHistoryMenuIv"
android:scaleX="0.8"
android:scaleY="0.8"
android:src="@drawable/newtab_button" />
</FrameLayout>
<LinearLayout style="@style/VisHistoryMenuSideLayout">
<View style="@style/VisHistoryEmptyView" />
<FrameLayout
android:id="@+id/vgTrash"
style="@style/VisHistoryFrLayoutMenu">
<ImageView
style="@style/VisHistoryMenuIv"
android:scaleX="1.3"
android:scaleY="1.3"
android:src="@drawable/trash" />
</FrameLayout>
<View style="@style/VisHistoryEmptyView" />
<FrameLayout
android:id="@+id/vgSettingsHis"
style="@style/VisHistoryFrLayoutMenu"
android:paddingLeft="0.0dip"
android:paddingRight="0.0dip">
<android.support.v7.widget.AppCompatImageView
style="@style/VisHistoryMenuIv"
android:layout_gravity="right"
app:srcCompat="@drawable/ic_dots_vertical"
tools:ignore="VectorDrawableCompat" />
</FrameLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</FrameLayout>
</LinearLayout>
这是另一个Fragment
这里将显示列表
public class FragmentVisualHistoryVertical extends FragmentVisualHistory implements VisualRecyclerAdapter.OnVisualHistoryItemListener {
public View paramView;
private VisualRecyclerAdapter mVisualHistoryRecyclerAdapter;
private RecyclerView mRecyclerView;
private VisualHistoryRepository getmNoteRepository;
private ArrayList<VisualHistoryItem> mVisualHistoryItems = new ArrayList<>();
@Override
public void onAttach(Context context) {
super.onAttach(context);
mContext = context;
}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
paramView = inflater.inflate(R.layout.fragment_vis_history_vertical, container, false);
mRecyclerView = paramView.findViewById(R.id.rvWebHistory);
initRecyclerView();
getmNoteRepository = new VisualHistoryRepository(getActivity());
retrieveVisualHistory();
return paramView;
}
private void initRecyclerView(){
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(linearLayoutManager);
linearLayoutManager.setReverseLayout(true);
new ItemTouchHelper(itemTouchHelperCallback).attachToRecyclerView(mRecyclerView);
mVisualHistoryRecyclerAdapter = new VisualRecyclerAdapter(mVisualHistoryItems, this, mContext);
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(mRecyclerView.getContext(),
linearLayoutManager.getOrientation());
mRecyclerView.addItemDecoration(dividerItemDecoration);
mRecyclerView.setAdapter(mVisualHistoryRecyclerAdapter);
}
private void retrieveVisualHistory() {
getmNoteRepository.retrieveVisualHistoryTask().observe(this, new Observer<List<VisualHistoryItem>>() {
@Override
public void onChanged(@Nullable List<VisualHistoryItem> item) {
if(mVisualHistoryItems.size() > 0){
mVisualHistoryItems.clear();
}
if(item != null){
mVisualHistoryItems.addAll(item);
}
mVisualHistoryRecyclerAdapter.notifyDataSetChanged();
}
});
}
@Override
public void onItemClicked(int position) {
}
private void deleteNote(VisualHistoryItem item) {
mVisualHistoryItems.remove(item);
mVisualHistoryRecyclerAdapter.notifyDataSetChanged();
getmNoteRepository.deleteVisualHistoryTask(item);
}
ItemTouchHelper.SimpleCallback itemTouchHelperCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
deleteNote(mVisualHistoryItems.get(viewHolder.getAdapterPosition()));
}
};
}
这是XML.
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:aapt="http://schemas.android.com/aapt" android:id="@+id/rvWebHistory" android:layout_width="match_parent" android:layout_height="match_parent"/>
这是room db
@Database(entities = {VisualHistoryItem.class}, version = 1)
public abstract class VisualHistoryDB extends RoomDatabase {
private static final String DATABASE_NAME = "visualHistory_db";
private static VisualHistoryDB instance;
public static VisualHistoryDB getInstance(final Context context) {
if (instance == null) {
instance = Room.databaseBuilder(
context.getApplicationContext(),
VisualHistoryDB.class,
DATABASE_NAME
).build();
}
return instance;
}
public abstract VisualHistoryDao getVisualHistoryDao();
}
这room db Dao
@Dao
public interface VisualHistoryDao {
@Insert
long[] insertVisualHistory(VisualHistoryItem... visualHistoryItems);
@Query("SELECT * FROM visualHistory")
LiveData<List<VisualHistoryItem>> getVisualHistory();
@Delete
int delete(VisualHistoryItem... visualHistoryItems);
}
这是pojo.class
@Entity(tableName = "visualHistory")
public class VisualHistoryItem implements Parcelable {
@PrimaryKey(autoGenerate = true)
private int id;
@ColumnInfo(name = "title")
private String title;
@ColumnInfo(name = "url")
private String url;
public VisualHistoryItem(int id, String title, String url) {
this.id = id;
this.title = title;
this.url = url;
}
@Ignore
public VisualHistoryItem() {
}
protected VisualHistoryItem(Parcel in) {
id = in.readInt();
title = in.readString();
url = in.readString();
}
public static final Creator<VisualHistoryItem> CREATOR = new Creator<VisualHistoryItem>() {
@Override
public VisualHistoryItem createFromParcel(Parcel in) {
return new VisualHistoryItem(in);
}
@Override
public VisualHistoryItem[] newArray(int size) {
return new VisualHistoryItem[size];
}
};
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
@Override
public String toString() {
return "VisualHistoryItem{" +
"id=" + id +
", title='" + title + '\'' +
", url='" + url + '\'' +
'}';
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel parcel, int flags) {
parcel.writeInt(id);
parcel.writeString(title);
parcel.writeString(url);
}
}
这就是Adapter.
public class VisualRecyclerAdapter extends RecyclerView.Adapter<VisualRecyclerAdapter.ViewHolder> {
private ArrayList<VisualHistoryItem> mVisualHistoryItem = new ArrayList<>();
private OnVisualHistoryItemListener mItemListener;
private final Context context;
public VisualRecyclerAdapter(ArrayList<VisualHistoryItem> mVisualHistoryItem, OnVisualHistoryItemListener mItemListener, Context context) {
this.context = context;
this.mVisualHistoryItem = mVisualHistoryItem;
this.mItemListener = mItemListener;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.fragment_visual_history, viewGroup, false);
return new ViewHolder(view, mItemListener);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {
Resources res = viewHolder.itemView.getContext().getResources();
viewHolder.visFragmentMain.setBackgroundColor(res.getColor(R.color.blue_text));
viewHolder.tvPageUrl.setText(mVisualHistoryItem.get(i).getUrl());
viewHolder.tvPageName.setText(mVisualHistoryItem.get(i).getTitle());
Bitmap bmp = null;
String filename = mVisualHistoryItem.get(i).getId()+".png";
try {
FileInputStream is = context.openFileInput(filename);
bmp = BitmapFactory.decodeStream(is);
is.close();
} catch (Exception e) {
e.printStackTrace();
}
if (bmp!=null) {
BitmapDrawable ob = new BitmapDrawable(context.getResources(), bmp);
viewHolder.ivVisualHistory.setBackground(ob);
}
}
@Override
public int getItemCount() {
return mVisualHistoryItem.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
ImageView ivVisualHistory;
OnVisualHistoryItemListener itemListener;
TextView tvPageName, tvPageUrl;
RelativeLayout visFragmentMain;
CardView cardView;
public ViewHolder(@NonNull View itemView, OnVisualHistoryItemListener mItemListener) {
super(itemView);
itemListener = mItemListener;
ivVisualHistory = itemView.findViewById(R.id.ivVisualHistory);
visFragmentMain = itemView.findViewById(R.id.visFragmentMain);
tvPageName = itemView.findViewById(R.id.tvPageName);
tvPageUrl = itemView.findViewById(R.id.tvPageUrl);
cardView = itemView.findViewById(R.id.cardView);
}
@Override
public void onClick(View v) {
itemListener.onItemClicked(getAdapterPosition());
}
}
public interface OnVisualHistoryItemListener {
void onItemClicked(int position);
}
}
这就是我想要达到的目标。
这是我的真实看法。
解决方案
好吧，您可以获取网站的 favicon 并使用此处解释的 android 的 Palette 类来获取 url 的突出颜色，如果您想获取快照，您可以在启动另一个活动之前保存快照并保存实例数据。要拍摄快照，您可以在创建 util 类后使用 Takesnapshot 肉类，代码如下：
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.view.View;
class Util {
static Bitmap takeScreenShot(Activity activity) {
View view = activity.getWindow().getDecorView();
view.setDrawingCacheEnabled(true);
view.buildDrawingCache();
Bitmap b1 = view.getDrawingCache();
Rect frame = new Rect();
activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
int statusBarHeight = frame.top;
//Find the screen dimensions to create bitmap in the same size.
int width = activity.getWindowManager().getDefaultDisplay().getWidth();
int height = activity.getWindowManager().getDefaultDisplay().getHeight();
Bitmap b = Bitmap.createBitmap(b1, 0, statusBarHeight, width, height - statusBarHeight);
view.destroyDrawingCache();
return b;
}
}
在您的活动中使用它将其保存为 png 文件，如下所示：
Bitmap topass=Util.takeScreenShot(this);
try {
//Write file
String filename = "bitmap.png";
FileOutputStream stream = this.openFileOutput(filename, Context.MODE_PRIVATE);
topass.compress(Bitmap.CompressFormat.PNG, 100, stream);
//Cleanup
stream.close();
topass.recycle();
} catch (Exception e) {
e.printStackTrace();
}
不要使用名称“bitmap.png”，而是使用您的“id.png”（String.valueof（id）+“.png”），因为您已将int“id”名称放入您的数据库中。您可以使用其 ID 保存每个活动的屏幕截图，并且每当您构建它的卡片视图时，以“id.png”的名称显示屏幕截图。要显示屏幕截图，您可以使用
Bitmap bmp = null;
String filename = String.valueof(getId())+".png";
try {
FileInputStream is = this.openFileInput(filename);
bmp = BitmapFactory.decodeStream(is);
is.close();
} catch (Exception e) {
e.printStackTrace();
}
if(bmp!=null)
{
ConstraintLayout cl =findViewById(R.id.shopbk); //it can be your any view
BitmapDrawable ob = new BitmapDrawable(getResources(), bmp);
cl.setBackground(ob); /* you should use glide here to show bitmap drawable as your preview will be very small as compared to screenshot actual size*/
}
并且就获取颜色（您说链接不起作用）而言，您可以首先使用获取位图
try {
URL url = new URL("http://..somepath url../favicon.ico");
Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch(IOException e) {
System.out.println(e);
}
然后使用调色板提取颜色
Palette.generateAsync(image, new Palette.PaletteAsyncListener() {
public void onGenerated(Palette palette) {
// Do something with colors...
}
});
为此，您将需要实现一个依赖项
dependencies {
...
compile 'com.android.support:palette-v7:21.0.+'
}
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