江心磐 江心磐
追梦者,总是在追寻心底那一缕若有若无的悸动,仿佛在逝去的梦中曾见,如今它又在何方。恍惚间已经无法回到从前...
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使用include多次引用同一个布局文件在跳转到该界面时变慢 我不用include直接在xml中写全部控件,相当于用一次include还感觉不到延迟,而如果用include引用一次就会感到明显的跳转延迟,多引用几次延迟更是多达好几秒。 这是我的引用xml: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://tieba.baidu.com/mo/q/checkurl?url=http%3A%2F%2Fschemas.android.com%2Fapk%2Fres%2Fandroid&urlrefer=cc882df92c96a5c2ac087a3d5bd884d4" xmlns:tools="http://tieba.baidu.com/mo/q/checkurl?url=http%3A%2F%2Fschemas.android.com%2Ftools&urlrefer=03b422231370478e1d7f1e0eb53dcbb4" android:layout_width="match_parent" android:layout_height="50dp" android:background="@drawable/yangpizhi" android:padding="3dp"> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView" android:background="@drawable/card_bg_3_0" android:padding="3dp" /> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView3" android:background="@drawable/card_bg_3_0" android:padding="3dp" android:layout_alignParentRight="true" /> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView2" android:background="@drawable/card_bg_3_0" android:padding="3dp" android:layout_toLeftOf="@id/imageView3" /> <LinearLayout android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="50dp" android:id="@+id/layout2" android:layout_toRightOf="@id/imageView" android:layout_toLeftOf="@id/imageView2" > <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="20dp" android:weightSum="4"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="最小:" android:id="@+id/textView" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall" android:text="Small Text" android:id="@+id/textView2" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="最大:" android:id="@+id/textView3" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall" android:text="Small Text" android:id="@+id/textView4" /> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="30dp" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:text="Large Text" android:id="@+id/textView5" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="Medium Text" android:id="@+id/textView6" /> </LinearLayout> </LinearLayout> </RelativeLayout> 其实并不复杂,就是几个控件和几个嵌套的布局,而且使用include不是应该效率提高吗?为什么反而更慢了? 如果全部放到界面xml里写,几个相同的加起来控件太多了。。。
使用include多次引用同一个布局文件在加载界面时变慢 我不用include直接在xml中写全部控件,相当于用一次include还感觉不到延迟,而如果用include引用一次就会感到明显的跳转延迟,多引用几次延迟更是多达好几秒。 这是我的引用xml: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://tieba.baidu.com/mo/q/checkurl?url=http%3A%2F%2Fschemas.android.com%2Fapk%2Fres%2Fandroid&urlrefer=cc882df92c96a5c2ac087a3d5bd884d4" xmlns:tools="http://tieba.baidu.com/mo/q/checkurl?url=http%3A%2F%2Fschemas.android.com%2Ftools&urlrefer=03b422231370478e1d7f1e0eb53dcbb4" android:layout_width="match_parent" android:layout_height="50dp" android:background="@drawable/yangpizhi" android:padding="3dp"> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView" android:background="@drawable/card_bg_3_0" android:padding="3dp" /> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView3" android:background="@drawable/card_bg_3_0" android:padding="3dp" android:layout_alignParentRight="true" /> <ImageView android:layout_width="50dp" android:layout_height="50dp" android:id="@+id/imageView2" android:background="@drawable/card_bg_3_0" android:padding="3dp" android:layout_toLeftOf="@id/imageView3" /> <LinearLayout android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="50dp" android:id="@+id/layout2" android:layout_toRightOf="@id/imageView" android:layout_toLeftOf="@id/imageView2" > <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="20dp" android:weightSum="4"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="最小:" android:id="@+id/textView" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall" android:text="Small Text" android:id="@+id/textView2" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="最大:" android:id="@+id/textView3" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall" android:text="Small Text" android:id="@+id/textView4" /> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="30dp" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:text="Large Text" android:id="@+id/textView5" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:text="Medium Text" android:id="@+id/textView6" /> </LinearLayout> </LinearLayout> </RelativeLayout> 其实并不复杂,就是几个控件和几个嵌套的布局,而且使用include不是应该效率提高吗?为什么反而更慢了? 如果全部放到界面xml里写,几个相同的加起来控件太多了。。。
关于SQLite数据库名的疑问 辅助类DatabaseHelper 如下: package com.example.administrator.myapp1; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; /** * Created by Administrator on 2016-05-31. */ public class DatabaseHelper extends SQLiteOpenHelper { public DatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { super(context, name, factory, version); } //辅助类建立时运行该方法 @Override public void onCreate(SQLiteDatabase db) { String sql = "CREATE TABLE CARD (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL , fileName VARCHAR, description VARCHAR)"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } } 实现代码: String dbname="db_sds"; String tablename_card="CARD"; String fileName="fileName"; String description="description"; DatabaseHelper mOpenHelper=new DatabaseHelper(this,dbname,null,124); SQLiteDatabase db=mOpenHelper.getWritableDatabase(); String sql1="insert into "+tablename_card+"("+fileName+","+description+") values('lilei','man');"; textView.setText(sql1); db.execSQL(sql1); setTitle("插入成功"); 按理说,DatabaseHelper mOpenHelper=new DatabaseHelper(this,dbname,null,124);这句应该是创建一个名为dbname的数据库,可是我试了出错。而如果dbname换成tablename_card就没问题,可是我现在是在创建数据库,为什么要用表名才正确?
关于SQLite数据库名的疑问 辅助类DatabaseHelper 如下: package com.example.administrator.myapp1; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; /** * Created by Administrator on 2016-05-31. */ public class DatabaseHelper extends SQLiteOpenHelper { public DatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { super(context, name, factory, version); } //辅助类建立时运行该方法 @Override public void onCreate(SQLiteDatabase db) { String sql = "CREATE TABLE CARD (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL , fileName VARCHAR, description VARCHAR)"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } } 实现代码: String dbname="db_sds"; String tablename_card="CARD"; String fileName="fileName"; String description="description"; DatabaseHelper mOpenHelper=new DatabaseHelper(this,dbname,null,124); SQLiteDatabase db=mOpenHelper.getWritableDatabase(); String sql1="insert into "+tablename_card+"("+fileName+","+description+") values('lilei','man');"; textView.setText(sql1); db.execSQL(sql1); setTitle("插入成功"); 按理说,DatabaseHelper mOpenHelper=new DatabaseHelper(this,dbname,null,124);这句应该是创建一个名为dbname的数据库,可是我试了出错。而如果dbname换成tablename_card就没问题,可是我现在是在创建数据库,为什么要用表名才正确?
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