Java
1.数据类型
bit(位):0或1计算机存储处理信息的最基本的单位
byte(字节):8个bit(上面表格数字的单位是byte)
2.
m与n数值交换 //m=2,n=3;
m=m^n; //m=2^3
n =m^n; //n =2^3^3=2
m=m^n; //m=2^3^2=3
3.
数组转集合,集合默认排(升)序
List<Integer> list = Arrays.asList(3,-3,0,0);
Collections.sort(list);
Android
1.project路径不能有中文与空格
2.进程间共享数据方式
a.共享文件
b.provider
c.AIDL(双向传递)
d.Messenger(客户端向服务端传递数据)
3.手机适配
a.语言适配
b.屏幕适配
c.SDK平台适配
4.接收网络图片
Bitmap bitmap = BitmapFactory.decodeStream(connection.getInputStream());
5.fillViewport
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:overScrollMode="never" />
<LinearLayout
android:id="@+id/layout_bottom"
android:layout_width="wrap_content"
android:layout_height="45dp"
android:layout_gravity="center_horizontal"
android:gravity="center_vertical"
android:visibility="gone">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="已经到底啦!"
android:textColor="@color/gray_b"
android:textSize="14dp" />
<TextView
android:id="@+id/tv_get_order"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:padding="5dp"
android:text="去接单 >"
android:textColor="@color/green"
android:textSize="14dp" />
</LinearLayout>
</LinearLayout>
</androidx.core.widget.NestedScrollView>
6.xml根布局
android:fitsSystemWindows="false"
7.padding 可滚动
android:clipToPadding="false"
8.可变高度viewpager
<com.ls365.lvtu.view.DynamicHeightViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
import android.content.Context
import android.util.AttributeSet
import androidx.viewpager.widget.ViewPager
/**
* author : fgl
* time : 2020/03/26
* desc :工具-日期计算-根据子view动态高度viewpager
*/
class DynamicHeightViewPager : ViewPager {
/**
* Constructor
*
* @param context the context
*/
constructor(context: Context): super(context)
/**
* Constructor
*
* @param context the context
* @param attrs the attribute set
*/
constructor(context: Context, attrs: AttributeSet): super(context, attrs)
/**
* 解决pager中视图高度不一致的情况 动态更改pager高度
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
var heightMeasureSpec: Int
val index = currentItem
var height = 0
val v = getChildAt(index)
if (v != null) {
v.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED))
height = v.measuredHeight
}
heightMeasureSpec = MeasureSpec.makeMeasureSpec(height + 80, MeasureSpec.EXACTLY)
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
val pager = this
pager.addOnPageChangeListener(object : SimpleOnPageChangeListener() {
override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
}
override fun onPageScrollStateChanged(state: Int) {
if (state == 2) {
requestLayout()
}
}
})
}
}
9.
<?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="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@color/colorPrimary"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="vertical"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_margin="20dp"
android:src="@mipmap/ic_launcher_round" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:gravity="center"
android:text="phone"
android:textSize="24dp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal">
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center"
android:text="tab1"
android:textSize="24dp" />
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:gravity="center"
android:text="tab2"
android:textSize="24dp" />
</LinearLayout>
</com.google.android.material.appbar.AppBarLayout>
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginBottom="10dp"
android:background="@color/cardview_dark_background"
android:gravity="center"
android:text="Title"
android:textSize="24dp" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
</LinearLayout>